spl_stake_pool/

processor.rs

//! Program state processor

use {
    crate::{
        error::StakePoolError,
        find_deposit_authority_program_address,
        inline_mpl_token_metadata::{
            self,
            instruction::{create_metadata_accounts_v3, update_metadata_accounts_v2},
            pda::find_metadata_account,
            state::DataV2,
        },
        instruction::{FundingType, PreferredValidatorType, StakePoolInstruction},
        minimum_delegation, minimum_reserve_lamports, minimum_stake_lamports,
        state::{
            is_extension_supported_for_mint, AccountType, Fee, FeeType, FutureEpoch, StakePool,
            StakeStatus, StakeWithdrawSource, ValidatorList, ValidatorListHeader,
            ValidatorStakeInfo,
        },
        AUTHORITY_DEPOSIT, AUTHORITY_WITHDRAW, EPHEMERAL_STAKE_SEED_PREFIX, MAX_VALIDATORS_IN_POOL,
        TRANSIENT_STAKE_SEED_PREFIX,
    },
    borsh::BorshDeserialize,
    num_traits::FromPrimitive,
    solana_program::{
        account_info::{next_account_info, AccountInfo},
        borsh1::try_from_slice_unchecked,
        clock::{Clock, Epoch},
        decode_error::DecodeError,
        entrypoint::ProgramResult,
        epoch_rewards::EpochRewards,
        msg,
        program::{invoke, invoke_signed},
        program_error::{PrintProgramError, ProgramError},
        pubkey::Pubkey,
        rent::Rent,
        sysvar::Sysvar,
    },
    solana_stake_interface as stake,
    solana_system_interface::{instruction as system_instruction, program as system_program},
    spl_token_2022::{
        check_spl_token_program_account,
        extension::{BaseStateWithExtensions, StateWithExtensions},
        native_mint,
        state::Mint,
    },
    std::num::NonZeroU32,
};

/// Deserialize the stake state from `AccountInfo`
fn get_stake_state(
    stake_account_info: &AccountInfo,
) -> Result<(stake::state::Meta, stake::state::Stake), ProgramError> {
    let stake_state =
        try_from_slice_unchecked::<stake::state::StakeStateV2>(&stake_account_info.data.borrow())?;
    match stake_state {
        stake::state::StakeStateV2::Stake(meta, stake, _) => Ok((meta, stake)),
        _ => Err(StakePoolError::WrongStakeStake.into()),
    }
}

/// Check validity of vote address for a particular stake account
fn check_validator_stake_address(
    program_id: &Pubkey,
    stake_pool_address: &Pubkey,
    stake_account_address: &Pubkey,
    vote_address: &Pubkey,
    seed: Option<NonZeroU32>,
) -> Result<(), ProgramError> {
    // Check stake account address validity
    let (validator_stake_address, _) =
        crate::find_stake_program_address(program_id, vote_address, stake_pool_address, seed);
    if validator_stake_address != *stake_account_address {
        msg!(
            "Incorrect stake account address for vote {}, expected {}, received {}",
            vote_address,
            validator_stake_address,
            stake_account_address
        );
        Err(StakePoolError::InvalidStakeAccountAddress.into())
    } else {
        Ok(())
    }
}

/// Check validity of vote address for a particular stake account
fn check_transient_stake_address(
    program_id: &Pubkey,
    stake_pool_address: &Pubkey,
    stake_account_address: &Pubkey,
    vote_address: &Pubkey,
    seed: u64,
) -> Result<u8, ProgramError> {
    // Check stake account address validity
    let (transient_stake_address, bump_seed) = crate::find_transient_stake_program_address(
        program_id,
        vote_address,
        stake_pool_address,
        seed,
    );
    if transient_stake_address != *stake_account_address {
        Err(StakePoolError::InvalidStakeAccountAddress.into())
    } else {
        Ok(bump_seed)
    }
}

/// Check address validity for an ephemeral stake account
fn check_ephemeral_stake_address(
    program_id: &Pubkey,
    stake_pool_address: &Pubkey,
    stake_account_address: &Pubkey,
    seed: u64,
) -> Result<u8, ProgramError> {
    // Check stake account address validity
    let (ephemeral_stake_address, bump_seed) =
        crate::find_ephemeral_stake_program_address(program_id, stake_pool_address, seed);
    if ephemeral_stake_address != *stake_account_address {
        Err(StakePoolError::InvalidStakeAccountAddress.into())
    } else {
        Ok(bump_seed)
    }
}

/// Check mpl metadata account address for the pool mint
fn check_mpl_metadata_account_address(
    metadata_address: &Pubkey,
    pool_mint: &Pubkey,
) -> Result<(), ProgramError> {
    let (metadata_account_pubkey, _) = find_metadata_account(pool_mint);
    if metadata_account_pubkey != *metadata_address {
        Err(StakePoolError::InvalidMetadataAccount.into())
    } else {
        Ok(())
    }
}

/// Check system program address
fn check_system_program(program_id: &Pubkey) -> Result<(), ProgramError> {
    if *program_id != system_program::id() {
        msg!(
            "Expected system program {}, received {}",
            system_program::id(),
            program_id
        );
        Err(ProgramError::IncorrectProgramId)
    } else {
        Ok(())
    }
}

/// Check stake program address
fn check_stake_program(program_id: &Pubkey) -> Result<(), ProgramError> {
    if *program_id != stake::program::id() {
        msg!(
            "Expected stake program {}, received {}",
            stake::program::id(),
            program_id
        );
        Err(ProgramError::IncorrectProgramId)
    } else {
        Ok(())
    }
}

/// Check mpl metadata program
fn check_mpl_metadata_program(program_id: &Pubkey) -> Result<(), ProgramError> {
    if *program_id != inline_mpl_token_metadata::id() {
        msg!(
            "Expected mpl metadata program {}, received {}",
            inline_mpl_token_metadata::id(),
            program_id
        );
        Err(ProgramError::IncorrectProgramId)
    } else {
        Ok(())
    }
}

/// Check account owner is the given program
fn check_account_owner(
    account_info: &AccountInfo,
    program_id: &Pubkey,
) -> Result<(), ProgramError> {
    if *program_id != *account_info.owner {
        msg!(
            "Expected account to be owned by program {}, received {}",
            program_id,
            account_info.owner
        );
        Err(ProgramError::IncorrectProgramId)
    } else {
        Ok(())
    }
}

/// Checks if a stake account can be managed by the pool
fn stake_is_usable_by_pool(
    meta: &stake::state::Meta,
    expected_authority: &Pubkey,
    expected_lockup: &stake::state::Lockup,
) -> bool {
    meta.authorized.staker == *expected_authority
        && meta.authorized.withdrawer == *expected_authority
        && meta.lockup == *expected_lockup
}

/// Checks if a stake account is active, without taking into account cool down
fn stake_is_inactive_without_history(stake: &stake::state::Stake, epoch: Epoch) -> bool {
    stake.delegation.deactivation_epoch < epoch
        || (stake.delegation.activation_epoch == epoch
            && stake.delegation.deactivation_epoch == epoch)
}

/// Roughly checks if a stake account is deactivating
fn check_if_stake_deactivating(
    account_info: &AccountInfo,
    vote_account_address: &Pubkey,
    epoch: Epoch,
) -> Result<(), ProgramError> {
    let (_, stake) = get_stake_state(account_info)?;
    if stake.delegation.deactivation_epoch != epoch {
        msg!(
            "Existing stake {} delegated to {} not deactivated in epoch {}",
            account_info.key,
            vote_account_address,
            epoch,
        );
        Err(StakePoolError::WrongStakeStake.into())
    } else {
        Ok(())
    }
}

/// Roughly checks if a stake account is activating
fn check_if_stake_activating(
    account_info: &AccountInfo,
    vote_account_address: &Pubkey,
    epoch: Epoch,
) -> Result<(), ProgramError> {
    let (_, stake) = get_stake_state(account_info)?;
    if stake.delegation.deactivation_epoch != Epoch::MAX
        || stake.delegation.activation_epoch != epoch
    {
        msg!(
            "Existing stake {} delegated to {} not activated in epoch {}",
            account_info.key,
            vote_account_address,
            epoch,
        );
        Err(StakePoolError::WrongStakeStake.into())
    } else {
        Ok(())
    }
}

/// Check that the stake state is correct: usable by the pool and delegated to
/// the expected validator
fn check_stake_state(
    stake_account_info: &AccountInfo,
    withdraw_authority: &Pubkey,
    vote_account_address: &Pubkey,
    lockup: &stake::state::Lockup,
) -> Result<(), ProgramError> {
    let (meta, stake) = get_stake_state(stake_account_info)?;
    if !stake_is_usable_by_pool(&meta, withdraw_authority, lockup) {
        msg!(
            "Validator stake for {} not usable by pool, must be owned by withdraw authority",
            vote_account_address
        );
        return Err(StakePoolError::WrongStakeStake.into());
    }
    if stake.delegation.voter_pubkey != *vote_account_address {
        msg!(
            "Validator stake {} not delegated to {}",
            stake_account_info.key,
            vote_account_address
        );
        return Err(StakePoolError::WrongStakeStake.into());
    }
    Ok(())
}

/// Checks if a validator stake account is valid, which means that it's usable
/// by the pool and delegated to the expected validator. These conditions can be
/// violated if a validator was force destaked during a cluster restart.
fn check_validator_stake_account(
    stake_account_info: &AccountInfo,
    program_id: &Pubkey,
    stake_pool: &Pubkey,
    withdraw_authority: &Pubkey,
    vote_account_address: &Pubkey,
    seed: u32,
    lockup: &stake::state::Lockup,
) -> Result<(), ProgramError> {
    check_account_owner(stake_account_info, &stake::program::id())?;
    check_validator_stake_address(
        program_id,
        stake_pool,
        stake_account_info.key,
        vote_account_address,
        NonZeroU32::new(seed),
    )?;
    check_stake_state(
        stake_account_info,
        withdraw_authority,
        vote_account_address,
        lockup,
    )?;
    Ok(())
}

/// Create a stake account on a PDA without transferring lamports
fn create_stake_account(
    stake_account_info: AccountInfo<'_>,
    stake_account_signer_seeds: &[&[u8]],
    stake_space: usize,
) -> Result<(), ProgramError> {
    invoke_signed(
        &system_instruction::allocate(stake_account_info.key, stake_space as u64),
        core::slice::from_ref(&stake_account_info),
        &[stake_account_signer_seeds],
    )?;
    invoke_signed(
        &system_instruction::assign(stake_account_info.key, &stake::program::id()),
        &[stake_account_info],
        &[stake_account_signer_seeds],
    )
}

/// Program state handler.
pub struct Processor {}
impl Processor {
    /// Issue a `delegate_stake` instruction.
    #[allow(clippy::too_many_arguments)]
    fn stake_delegate<'a>(
        stake_info: AccountInfo<'a>,
        vote_account_info: AccountInfo<'a>,
        clock_info: AccountInfo<'a>,
        stake_history_info: AccountInfo<'a>,
        stake_config_info: AccountInfo<'a>,
        authority_info: AccountInfo<'a>,
        stake_pool: &Pubkey,
        authority_type: &[u8],
        bump_seed: u8,
    ) -> Result<(), ProgramError> {
        let authority_signature_seeds = [stake_pool.as_ref(), authority_type, &[bump_seed]];
        let signers = &[&authority_signature_seeds[..]];

        let ix = stake::instruction::delegate_stake(
            stake_info.key,
            authority_info.key,
            vote_account_info.key,
        );

        invoke_signed(
            &ix,
            &[
                stake_info,
                vote_account_info,
                clock_info,
                stake_history_info,
                stake_config_info,
                authority_info,
            ],
            signers,
        )
    }

    /// Issue a `stake_deactivate` instruction.
    fn stake_deactivate<'a>(
        stake_info: AccountInfo<'a>,
        clock_info: AccountInfo<'a>,
        authority_info: AccountInfo<'a>,
        stake_pool: &Pubkey,
        authority_type: &[u8],
        bump_seed: u8,
    ) -> Result<(), ProgramError> {
        let authority_signature_seeds = [stake_pool.as_ref(), authority_type, &[bump_seed]];
        let signers = &[&authority_signature_seeds[..]];

        let ix = stake::instruction::deactivate_stake(stake_info.key, authority_info.key);

        invoke_signed(&ix, &[stake_info, clock_info, authority_info], signers)
    }

    /// Issue a `stake_split` instruction.
    fn stake_split<'a>(
        stake_pool: &Pubkey,
        stake_account: AccountInfo<'a>,
        authority: AccountInfo<'a>,
        authority_type: &[u8],
        bump_seed: u8,
        amount: u64,
        split_stake: AccountInfo<'a>,
    ) -> Result<(), ProgramError> {
        let authority_signature_seeds = [stake_pool.as_ref(), authority_type, &[bump_seed]];
        let signers = &[&authority_signature_seeds[..]];

        let split_instruction =
            stake::instruction::split(stake_account.key, authority.key, amount, split_stake.key);

        invoke_signed(
            split_instruction
                .last()
                .ok_or(ProgramError::InvalidInstructionData)?,
            &[stake_account, split_stake, authority],
            signers,
        )
    }

    /// Issue a `stake_merge` instruction.
    #[allow(clippy::too_many_arguments)]
    fn stake_merge<'a>(
        stake_pool: &Pubkey,
        source_account: AccountInfo<'a>,
        authority: AccountInfo<'a>,
        authority_type: &[u8],
        bump_seed: u8,
        destination_account: AccountInfo<'a>,
        clock: AccountInfo<'a>,
        stake_history: AccountInfo<'a>,
    ) -> Result<(), ProgramError> {
        let authority_signature_seeds = [stake_pool.as_ref(), authority_type, &[bump_seed]];
        let signers = &[&authority_signature_seeds[..]];

        let merge_instruction =
            stake::instruction::merge(destination_account.key, source_account.key, authority.key);

        invoke_signed(
            &merge_instruction[0],
            &[
                destination_account,
                source_account,
                clock,
                stake_history,
                authority,
            ],
            signers,
        )
    }

    /// Issue stake::instruction::authorize instructions to update both
    /// authorities
    fn stake_authorize<'a>(
        stake_account: AccountInfo<'a>,
        stake_authority: AccountInfo<'a>,
        new_stake_authority: &Pubkey,
        clock: AccountInfo<'a>,
    ) -> Result<(), ProgramError> {
        let authorize_instruction = stake::instruction::authorize(
            stake_account.key,
            stake_authority.key,
            new_stake_authority,
            stake::state::StakeAuthorize::Staker,
            None,
        );

        invoke(
            &authorize_instruction,
            &[
                stake_account.clone(),
                clock.clone(),
                stake_authority.clone(),
            ],
        )?;

        let authorize_instruction = stake::instruction::authorize(
            stake_account.key,
            stake_authority.key,
            new_stake_authority,
            stake::state::StakeAuthorize::Withdrawer,
            None,
        );

        invoke(
            &authorize_instruction,
            &[stake_account, clock, stake_authority],
        )
    }

    /// Issue stake::instruction::authorize instructions to update both
    /// authorities
    #[allow(clippy::too_many_arguments)]
    fn stake_authorize_signed<'a>(
        stake_pool: &Pubkey,
        stake_account: AccountInfo<'a>,
        stake_authority: AccountInfo<'a>,
        authority_type: &[u8],
        bump_seed: u8,
        new_stake_authority: &Pubkey,
        clock: AccountInfo<'a>,
    ) -> Result<(), ProgramError> {
        let authority_signature_seeds = [stake_pool.as_ref(), authority_type, &[bump_seed]];
        let signers = &[&authority_signature_seeds[..]];

        let authorize_instruction = stake::instruction::authorize(
            stake_account.key,
            stake_authority.key,
            new_stake_authority,
            stake::state::StakeAuthorize::Staker,
            None,
        );

        invoke_signed(
            &authorize_instruction,
            &[
                stake_account.clone(),
                clock.clone(),
                stake_authority.clone(),
            ],
            signers,
        )?;

        let authorize_instruction = stake::instruction::authorize(
            stake_account.key,
            stake_authority.key,
            new_stake_authority,
            stake::state::StakeAuthorize::Withdrawer,
            None,
        );
        invoke_signed(
            &authorize_instruction,
            &[stake_account, clock, stake_authority],
            signers,
        )
    }

    /// Issue stake::instruction::withdraw instruction to move additional
    /// lamports
    #[allow(clippy::too_many_arguments)]
    fn stake_withdraw<'a>(
        stake_pool: &Pubkey,
        source_account: AccountInfo<'a>,
        authority: AccountInfo<'a>,
        authority_type: &[u8],
        bump_seed: u8,
        destination_account: AccountInfo<'a>,
        clock: AccountInfo<'a>,
        stake_history: AccountInfo<'a>,
        lamports: u64,
    ) -> Result<(), ProgramError> {
        let authority_signature_seeds = [stake_pool.as_ref(), authority_type, &[bump_seed]];
        let signers = &[&authority_signature_seeds[..]];
        let custodian_pubkey = None;

        let withdraw_instruction = stake::instruction::withdraw(
            source_account.key,
            authority.key,
            destination_account.key,
            lamports,
            custodian_pubkey,
        );

        invoke_signed(
            &withdraw_instruction,
            &[
                source_account,
                destination_account,
                clock,
                stake_history,
                authority,
            ],
            signers,
        )
    }

    /// Issue a SPL Token `Burn` instruction.
    #[allow(clippy::too_many_arguments)]
    fn token_burn<'a>(
        token_program: AccountInfo<'a>,
        burn_account: AccountInfo<'a>,
        mint: AccountInfo<'a>,
        authority: AccountInfo<'a>,
        amount: u64,
    ) -> Result<(), ProgramError> {
        let ix = spl_token_2022::instruction::burn(
            token_program.key,
            burn_account.key,
            mint.key,
            authority.key,
            &[],
            amount,
        )?;

        invoke(&ix, &[burn_account, mint, authority])
    }

    /// Issue a SPL Token `MintTo` instruction.
    #[allow(clippy::too_many_arguments)]
    fn token_mint_to<'a>(
        stake_pool: &Pubkey,
        token_program: AccountInfo<'a>,
        mint: AccountInfo<'a>,
        destination: AccountInfo<'a>,
        authority: AccountInfo<'a>,
        authority_type: &[u8],
        bump_seed: u8,
        amount: u64,
    ) -> Result<(), ProgramError> {
        let authority_signature_seeds = [stake_pool.as_ref(), authority_type, &[bump_seed]];
        let signers = &[&authority_signature_seeds[..]];

        let ix = spl_token_2022::instruction::mint_to(
            token_program.key,
            mint.key,
            destination.key,
            authority.key,
            &[],
            amount,
        )?;

        invoke_signed(&ix, &[mint, destination, authority], signers)
    }

    /// Issue a SPL Token `Transfer` instruction.
    #[allow(clippy::too_many_arguments)]
    fn token_transfer<'a>(
        token_program: AccountInfo<'a>,
        source: AccountInfo<'a>,
        mint: AccountInfo<'a>,
        destination: AccountInfo<'a>,
        authority: AccountInfo<'a>,
        amount: u64,
        decimals: u8,
    ) -> Result<(), ProgramError> {
        let ix = spl_token_2022::instruction::transfer_checked(
            token_program.key,
            source.key,
            mint.key,
            destination.key,
            authority.key,
            &[],
            amount,
            decimals,
        )?;
        invoke(&ix, &[source, mint, destination, authority])
    }

    fn sol_transfer<'a>(
        source: AccountInfo<'a>,
        destination: AccountInfo<'a>,
        amount: u64,
    ) -> Result<(), ProgramError> {
        let ix = solana_program::system_instruction::transfer(source.key, destination.key, amount);
        invoke(&ix, &[source, destination])
    }

    /// Processes `Initialize` instruction.
    #[inline(never)] // needed due to stack size violation
    fn process_initialize(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        epoch_fee: Fee,
        withdrawal_fee: Fee,
        deposit_fee: Fee,
        referral_fee: u8,
        max_validators: u32,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let manager_info = next_account_info(account_info_iter)?;
        let staker_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let validator_list_info = next_account_info(account_info_iter)?;
        let reserve_stake_info = next_account_info(account_info_iter)?;
        let pool_mint_info = next_account_info(account_info_iter)?;
        let manager_fee_info = next_account_info(account_info_iter)?;
        let token_program_info = next_account_info(account_info_iter)?;

        let rent = Rent::get()?;

        if !manager_info.is_signer {
            msg!("Manager did not sign initialization");
            return Err(StakePoolError::SignatureMissing.into());
        }

        if stake_pool_info.key == validator_list_info.key {
            msg!("Cannot use same account for stake pool and validator list");
            return Err(StakePoolError::AlreadyInUse.into());
        }

        // This check is unnecessary since the runtime will check the ownership,
        // but provides clarity that the parameter is in fact checked.
        check_account_owner(stake_pool_info, program_id)?;
        let mut stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_uninitialized() {
            msg!("Provided stake pool already in use");
            return Err(StakePoolError::AlreadyInUse.into());
        }

        // This check is unnecessary since the runtime will check the ownership,
        // but provides clarity that the parameter is in fact checked.
        check_account_owner(validator_list_info, program_id)?;
        let mut validator_list =
            try_from_slice_unchecked::<ValidatorList>(&validator_list_info.data.borrow())?;
        if !validator_list.header.is_uninitialized() {
            msg!("Provided validator list already in use");
            return Err(StakePoolError::AlreadyInUse.into());
        }

        let data_length = validator_list_info.data_len();
        let expected_max_validators = ValidatorList::calculate_max_validators(data_length);
        if expected_max_validators != max_validators as usize || max_validators == 0 {
            msg!(
                "Incorrect validator list size provided, expected {}, provided {}",
                expected_max_validators,
                max_validators
            );
            return Err(StakePoolError::UnexpectedValidatorListAccountSize.into());
        }
        if max_validators > MAX_VALIDATORS_IN_POOL {
            return Err(StakePoolError::TooManyValidatorsInPool.into());
        }
        validator_list.header.account_type = AccountType::ValidatorList;
        validator_list.header.max_validators = max_validators;
        validator_list.validators.clear();

        if !rent.is_exempt(stake_pool_info.lamports(), stake_pool_info.data_len()) {
            msg!("Stake pool not rent-exempt");
            return Err(ProgramError::AccountNotRentExempt);
        }

        if !rent.is_exempt(
            validator_list_info.lamports(),
            validator_list_info.data_len(),
        ) {
            msg!("Validator stake list not rent-exempt");
            return Err(ProgramError::AccountNotRentExempt);
        }

        // Numerator should be smaller than or equal to denominator (fee <= 1)
        if epoch_fee.numerator > epoch_fee.denominator
            || withdrawal_fee.numerator > withdrawal_fee.denominator
            || deposit_fee.numerator > deposit_fee.denominator
            || referral_fee > 100u8
        {
            return Err(StakePoolError::FeeTooHigh.into());
        }

        check_spl_token_program_account(token_program_info.key)?;

        if pool_mint_info.owner != token_program_info.key {
            return Err(ProgramError::IncorrectProgramId);
        }

        stake_pool.token_program_id = *token_program_info.key;
        stake_pool.pool_mint = *pool_mint_info.key;

        let (stake_deposit_authority, sol_deposit_authority) =
            match next_account_info(account_info_iter) {
                Ok(deposit_authority_info) => (
                    *deposit_authority_info.key,
                    Some(*deposit_authority_info.key),
                ),
                Err(_) => (
                    find_deposit_authority_program_address(program_id, stake_pool_info.key).0,
                    None,
                ),
            };
        let (withdraw_authority_key, stake_withdraw_bump_seed) =
            crate::find_withdraw_authority_program_address(program_id, stake_pool_info.key);
        if withdraw_authority_key != *withdraw_authority_info.key {
            msg!(
                "Incorrect withdraw authority provided, expected {}, received {}",
                withdraw_authority_key,
                withdraw_authority_info.key
            );
            return Err(StakePoolError::InvalidProgramAddress.into());
        }

        {
            let pool_mint_data = pool_mint_info.try_borrow_data()?;
            let pool_mint = StateWithExtensions::<Mint>::unpack(&pool_mint_data)?;

            if pool_mint.base.supply != 0 {
                return Err(StakePoolError::NonZeroPoolTokenSupply.into());
            }

            if pool_mint.base.decimals != native_mint::DECIMALS {
                return Err(StakePoolError::IncorrectMintDecimals.into());
            }

            if !pool_mint
                .base
                .mint_authority
                .contains(&withdraw_authority_key)
            {
                return Err(StakePoolError::WrongMintingAuthority.into());
            }

            if pool_mint.base.freeze_authority.is_some() {
                return Err(StakePoolError::InvalidMintFreezeAuthority.into());
            }

            let extensions = pool_mint.get_extension_types()?;
            if extensions
                .iter()
                .any(|x| !is_extension_supported_for_mint(x))
            {
                return Err(StakePoolError::UnsupportedMintExtension.into());
            }
        }
        stake_pool.check_manager_fee_info(manager_fee_info)?;

        if *reserve_stake_info.owner != stake::program::id() {
            msg!("Reserve stake account not owned by stake program");
            return Err(ProgramError::IncorrectProgramId);
        }
        let stake_state = try_from_slice_unchecked::<stake::state::StakeStateV2>(
            &reserve_stake_info.data.borrow(),
        )?;
        let total_lamports = if let stake::state::StakeStateV2::Initialized(meta) = stake_state {
            if meta.lockup != stake::state::Lockup::default() {
                msg!("Reserve stake account has some lockup");
                return Err(StakePoolError::WrongStakeStake.into());
            }

            if meta.authorized.staker != withdraw_authority_key {
                msg!(
                    "Reserve stake account has incorrect staker {}, should be {}",
                    meta.authorized.staker,
                    withdraw_authority_key
                );
                return Err(StakePoolError::WrongStakeStake.into());
            }

            if meta.authorized.withdrawer != withdraw_authority_key {
                msg!(
                    "Reserve stake account has incorrect withdrawer {}, should be {}",
                    meta.authorized.staker,
                    withdraw_authority_key
                );
                return Err(StakePoolError::WrongStakeStake.into());
            }
            reserve_stake_info
                .lamports()
                .checked_sub(minimum_reserve_lamports(&meta))
                .ok_or(StakePoolError::CalculationFailure)?
        } else {
            msg!("Reserve stake account not in initialized state");
            return Err(StakePoolError::WrongStakeStake.into());
        };

        if total_lamports > 0 {
            Self::token_mint_to(
                stake_pool_info.key,
                token_program_info.clone(),
                pool_mint_info.clone(),
                manager_fee_info.clone(),
                withdraw_authority_info.clone(),
                AUTHORITY_WITHDRAW,
                stake_withdraw_bump_seed,
                total_lamports,
            )?;
        }

        borsh::to_writer(
            &mut validator_list_info.data.borrow_mut()[..],
            &validator_list,
        )?;

        stake_pool.account_type = AccountType::StakePool;
        stake_pool.manager = *manager_info.key;
        stake_pool.staker = *staker_info.key;
        stake_pool.stake_deposit_authority = stake_deposit_authority;
        stake_pool.stake_withdraw_bump_seed = stake_withdraw_bump_seed;
        stake_pool.validator_list = *validator_list_info.key;
        stake_pool.reserve_stake = *reserve_stake_info.key;
        stake_pool.manager_fee_account = *manager_fee_info.key;
        stake_pool.total_lamports = total_lamports;
        stake_pool.pool_token_supply = total_lamports;
        stake_pool.last_update_epoch = Clock::get()?.epoch;
        stake_pool.lockup = stake::state::Lockup::default();
        stake_pool.epoch_fee = epoch_fee;
        stake_pool.next_epoch_fee = FutureEpoch::None;
        stake_pool.preferred_deposit_validator_vote_address = None;
        stake_pool.preferred_withdraw_validator_vote_address = None;
        stake_pool.stake_deposit_fee = deposit_fee;
        stake_pool.stake_withdrawal_fee = withdrawal_fee;
        stake_pool.next_stake_withdrawal_fee = FutureEpoch::None;
        stake_pool.stake_referral_fee = referral_fee;
        stake_pool.sol_deposit_authority = sol_deposit_authority;
        stake_pool.sol_deposit_fee = deposit_fee;
        stake_pool.sol_referral_fee = referral_fee;
        stake_pool.sol_withdraw_authority = None;
        stake_pool.sol_withdrawal_fee = withdrawal_fee;
        stake_pool.next_sol_withdrawal_fee = FutureEpoch::None;
        stake_pool.last_epoch_pool_token_supply = 0;
        stake_pool.last_epoch_total_lamports = 0;

        borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)
            .map_err(|e| e.into())
    }

    /// Processes `AddValidatorToPool` instruction.
    #[inline(never)] // needed due to stack size violation
    fn process_add_validator_to_pool(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        raw_validator_seed: u32,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let staker_info = next_account_info(account_info_iter)?;
        let reserve_stake_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let validator_list_info = next_account_info(account_info_iter)?;
        let stake_info = next_account_info(account_info_iter)?;
        let validator_vote_info = next_account_info(account_info_iter)?;
        let rent_info = next_account_info(account_info_iter)?;
        let rent = &Rent::from_account_info(rent_info)?;
        let clock_info = next_account_info(account_info_iter)?;
        let clock = &Clock::from_account_info(clock_info)?;
        let stake_history_info = next_account_info(account_info_iter)?;
        let stake_config_info = next_account_info(account_info_iter)?;
        let system_program_info = next_account_info(account_info_iter)?;
        let stake_program_info = next_account_info(account_info_iter)?;

        check_system_program(system_program_info.key)?;
        check_stake_program(stake_program_info.key)?;

        check_account_owner(stake_pool_info, program_id)?;
        let stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        stake_pool.check_authority_withdraw(
            withdraw_authority_info.key,
            program_id,
            stake_pool_info.key,
        )?;

        stake_pool.check_staker(staker_info)?;
        stake_pool.check_reserve_stake(reserve_stake_info)?;
        stake_pool.check_validator_list(validator_list_info)?;

        if stake_pool.last_update_epoch < clock.epoch {
            return Err(StakePoolError::StakeListAndPoolOutOfDate.into());
        }

        check_account_owner(validator_list_info, program_id)?;
        let mut validator_list_data = validator_list_info.data.borrow_mut();
        let (header, mut validator_list) =
            ValidatorListHeader::deserialize_vec(&mut validator_list_data)?;
        if !header.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }
        if header.max_validators == validator_list.len() {
            return Err(ProgramError::AccountDataTooSmall);
        }
        if validator_list.len() >= MAX_VALIDATORS_IN_POOL {
            return Err(StakePoolError::TooManyValidatorsInPool.into());
        }
        let maybe_validator_stake_info = validator_list.find::<ValidatorStakeInfo, _>(|x| {
            ValidatorStakeInfo::memcmp_pubkey(x, validator_vote_info.key)
        });
        if maybe_validator_stake_info.is_some() {
            return Err(StakePoolError::ValidatorAlreadyAdded.into());
        }

        let validator_seed = NonZeroU32::new(raw_validator_seed);
        let (stake_address, bump_seed) = crate::find_stake_program_address(
            program_id,
            validator_vote_info.key,
            stake_pool_info.key,
            validator_seed,
        );
        if stake_address != *stake_info.key {
            return Err(StakePoolError::InvalidStakeAccountAddress.into());
        }

        let validator_seed_bytes = validator_seed.map(|s| s.get().to_le_bytes());
        let stake_account_signer_seeds: &[&[_]] = &[
            validator_vote_info.key.as_ref(),
            stake_pool_info.key.as_ref(),
            validator_seed_bytes
                .as_ref()
                .map(|s| s.as_slice())
                .unwrap_or(&[]),
            &[bump_seed],
        ];

        // Fund the stake account with the minimum + rent-exempt balance
        let stake_space = std::mem::size_of::<stake::state::StakeStateV2>();
        let stake_minimum_delegation = stake::tools::get_minimum_delegation()?;
        let required_lamports = minimum_delegation(stake_minimum_delegation)
            .saturating_add(rent.minimum_balance(stake_space));

        // Check that we're not draining the reserve totally
        let reserve_stake = try_from_slice_unchecked::<stake::state::StakeStateV2>(
            &reserve_stake_info.data.borrow(),
        )?;
        let reserve_meta = reserve_stake
            .meta()
            .ok_or(StakePoolError::WrongStakeStake)?;
        let minimum_lamports = minimum_reserve_lamports(&reserve_meta);
        let reserve_lamports = reserve_stake_info.lamports();
        if reserve_lamports.saturating_sub(required_lamports) < minimum_lamports {
            msg!(
                "Need to add {} lamports for the reserve stake to be rent-exempt after adding a validator, reserve currently has {} lamports",
                required_lamports.saturating_add(minimum_lamports).saturating_sub(reserve_lamports),
                reserve_lamports
            );
            return Err(ProgramError::InsufficientFunds);
        }

        // Create new stake account
        create_stake_account(stake_info.clone(), stake_account_signer_seeds, stake_space)?;
        // split into validator stake account
        Self::stake_split(
            stake_pool_info.key,
            reserve_stake_info.clone(),
            withdraw_authority_info.clone(),
            AUTHORITY_WITHDRAW,
            stake_pool.stake_withdraw_bump_seed,
            required_lamports,
            stake_info.clone(),
        )?;

        Self::stake_delegate(
            stake_info.clone(),
            validator_vote_info.clone(),
            clock_info.clone(),
            stake_history_info.clone(),
            stake_config_info.clone(),
            withdraw_authority_info.clone(),
            stake_pool_info.key,
            AUTHORITY_WITHDRAW,
            stake_pool.stake_withdraw_bump_seed,
        )?;

        validator_list.push(ValidatorStakeInfo {
            status: StakeStatus::Active.into(),
            vote_account_address: *validator_vote_info.key,
            active_stake_lamports: required_lamports.into(),
            transient_stake_lamports: 0.into(),
            last_update_epoch: clock.epoch.into(),
            transient_seed_suffix: 0.into(),
            unused: 0.into(),
            validator_seed_suffix: raw_validator_seed.into(),
        })?;

        Ok(())
    }

    /// Processes `RemoveValidatorFromPool` instruction.
    #[inline(never)] // needed due to stack size violation
    fn process_remove_validator_from_pool(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let staker_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let validator_list_info = next_account_info(account_info_iter)?;
        let stake_account_info = next_account_info(account_info_iter)?;
        let transient_stake_account_info = next_account_info(account_info_iter)?;
        let clock_info = next_account_info(account_info_iter)?;
        let clock = &Clock::from_account_info(clock_info)?;
        let stake_program_info = next_account_info(account_info_iter)?;

        check_stake_program(stake_program_info.key)?;
        check_account_owner(stake_pool_info, program_id)?;

        let mut stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        stake_pool.check_authority_withdraw(
            withdraw_authority_info.key,
            program_id,
            stake_pool_info.key,
        )?;
        stake_pool.check_staker(staker_info)?;

        if stake_pool.last_update_epoch < clock.epoch {
            msg!(
                "clock {} pool {}",
                clock.epoch,
                stake_pool.last_update_epoch
            );
            return Err(StakePoolError::StakeListAndPoolOutOfDate.into());
        }

        stake_pool.check_validator_list(validator_list_info)?;

        check_account_owner(validator_list_info, program_id)?;
        let mut validator_list_data = validator_list_info.data.borrow_mut();
        let (header, mut validator_list) =
            ValidatorListHeader::deserialize_vec(&mut validator_list_data)?;
        if !header.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        let (_, stake) = get_stake_state(stake_account_info)?;
        let vote_account_address = stake.delegation.voter_pubkey;
        let maybe_validator_stake_info = validator_list.find_mut::<ValidatorStakeInfo, _>(|x| {
            ValidatorStakeInfo::memcmp_pubkey(x, &vote_account_address)
        });
        if maybe_validator_stake_info.is_none() {
            msg!(
                "Vote account {} not found in stake pool",
                vote_account_address
            );
            return Err(StakePoolError::ValidatorNotFound.into());
        }
        let validator_stake_info = maybe_validator_stake_info.unwrap();
        check_validator_stake_address(
            program_id,
            stake_pool_info.key,
            stake_account_info.key,
            &vote_account_address,
            NonZeroU32::new(validator_stake_info.validator_seed_suffix.into()),
        )?;

        if validator_stake_info.status != StakeStatus::Active.into() {
            msg!("Validator is already marked for removal");
            return Err(StakePoolError::ValidatorNotFound.into());
        }

        let new_status = if u64::from(validator_stake_info.transient_stake_lamports) > 0 {
            check_transient_stake_address(
                program_id,
                stake_pool_info.key,
                transient_stake_account_info.key,
                &vote_account_address,
                validator_stake_info.transient_seed_suffix.into(),
            )?;

            match get_stake_state(transient_stake_account_info) {
                Ok((meta, stake))
                    if stake_is_usable_by_pool(
                        &meta,
                        withdraw_authority_info.key,
                        &stake_pool.lockup,
                    ) =>
                {
                    if stake.delegation.deactivation_epoch == Epoch::MAX {
                        Self::stake_deactivate(
                            transient_stake_account_info.clone(),
                            clock_info.clone(),
                            withdraw_authority_info.clone(),
                            stake_pool_info.key,
                            AUTHORITY_WITHDRAW,
                            stake_pool.stake_withdraw_bump_seed,
                        )?;
                    }
                }
                _ => (),
            }
            StakeStatus::DeactivatingAll
        } else {
            StakeStatus::DeactivatingValidator
        };

        // If the stake was force-deactivated through deactivate-delinquent or
        // some other means, we *do not* need to deactivate it again
        if stake.delegation.deactivation_epoch == Epoch::MAX {
            Self::stake_deactivate(
                stake_account_info.clone(),
                clock_info.clone(),
                withdraw_authority_info.clone(),
                stake_pool_info.key,
                AUTHORITY_WITHDRAW,
                stake_pool.stake_withdraw_bump_seed,
            )?;
        }

        validator_stake_info.status = new_status.into();

        if stake_pool.preferred_deposit_validator_vote_address == Some(vote_account_address) {
            stake_pool.preferred_deposit_validator_vote_address = None;
        }
        if stake_pool.preferred_withdraw_validator_vote_address == Some(vote_account_address) {
            stake_pool.preferred_withdraw_validator_vote_address = None;
        }
        borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)?;

        Ok(())
    }

    /// Processes `DecreaseValidatorStake` instruction.
    #[inline(never)] // needed due to stack size violation
    fn process_decrease_validator_stake(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        lamports: u64,
        transient_stake_seed: u64,
        maybe_ephemeral_stake_seed: Option<u64>,
        fund_rent_exempt_reserve: bool,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let staker_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let validator_list_info = next_account_info(account_info_iter)?;
        let maybe_reserve_stake_info = fund_rent_exempt_reserve
            .then(|| next_account_info(account_info_iter))
            .transpose()?;
        let validator_stake_account_info = next_account_info(account_info_iter)?;
        let maybe_ephemeral_stake_account_info = maybe_ephemeral_stake_seed
            .map(|_| next_account_info(account_info_iter))
            .transpose()?;
        let transient_stake_account_info = next_account_info(account_info_iter)?;
        let clock_info = next_account_info(account_info_iter)?;
        let clock = &Clock::from_account_info(clock_info)?;
        let (rent, maybe_stake_history_info) =
            if maybe_ephemeral_stake_seed.is_some() || fund_rent_exempt_reserve {
                (Rent::get()?, Some(next_account_info(account_info_iter)?))
            } else {
                // legacy instruction takes the rent account
                let rent_info = next_account_info(account_info_iter)?;
                (Rent::from_account_info(rent_info)?, None)
            };
        let system_program_info = next_account_info(account_info_iter)?;
        let stake_program_info = next_account_info(account_info_iter)?;

        check_system_program(system_program_info.key)?;
        check_stake_program(stake_program_info.key)?;
        check_account_owner(stake_pool_info, program_id)?;

        let stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            msg!("Expected valid stake pool");
            return Err(StakePoolError::InvalidState.into());
        }

        stake_pool.check_authority_withdraw(
            withdraw_authority_info.key,
            program_id,
            stake_pool_info.key,
        )?;
        stake_pool.check_staker(staker_info)?;

        if stake_pool.last_update_epoch < clock.epoch {
            return Err(StakePoolError::StakeListAndPoolOutOfDate.into());
        }

        stake_pool.check_validator_list(validator_list_info)?;
        check_account_owner(validator_list_info, program_id)?;
        let validator_list_data = &mut *validator_list_info.data.borrow_mut();
        let (validator_list_header, mut validator_list) =
            ValidatorListHeader::deserialize_vec(validator_list_data)?;
        if !validator_list_header.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        if let Some(reserve_stake_info) = maybe_reserve_stake_info {
            stake_pool.check_reserve_stake(reserve_stake_info)?;
        }

        let (meta, stake) = get_stake_state(validator_stake_account_info)?;
        let vote_account_address = stake.delegation.voter_pubkey;

        let maybe_validator_stake_info = validator_list.find_mut::<ValidatorStakeInfo, _>(|x| {
            ValidatorStakeInfo::memcmp_pubkey(x, &vote_account_address)
        });
        if maybe_validator_stake_info.is_none() {
            msg!(
                "Vote account {} not found in stake pool",
                vote_account_address
            );
            return Err(StakePoolError::ValidatorNotFound.into());
        }
        let validator_stake_info = maybe_validator_stake_info.unwrap();
        check_validator_stake_address(
            program_id,
            stake_pool_info.key,
            validator_stake_account_info.key,
            &vote_account_address,
            NonZeroU32::new(validator_stake_info.validator_seed_suffix.into()),
        )?;
        if u64::from(validator_stake_info.transient_stake_lamports) > 0 {
            if maybe_ephemeral_stake_seed.is_none() {
                msg!("Attempting to decrease stake on a validator with pending transient stake, use DecreaseAdditionalValidatorStake with the existing seed");
                return Err(StakePoolError::TransientAccountInUse.into());
            }
            if transient_stake_seed != u64::from(validator_stake_info.transient_seed_suffix) {
                msg!(
                    "Transient stake already exists with seed {}, you must use that one",
                    u64::from(validator_stake_info.transient_seed_suffix)
                );
                return Err(ProgramError::InvalidSeeds);
            }
            check_if_stake_deactivating(
                transient_stake_account_info,
                &vote_account_address,
                clock.epoch,
            )?;
        }

        if validator_stake_info.status != StakeStatus::Active.into() {
            msg!("Validator is marked for removal and no longer allows decreases");
            return Err(StakePoolError::ValidatorNotFound.into());
        }

        let stake_space = std::mem::size_of::<stake::state::StakeStateV2>();
        let stake_rent = rent.minimum_balance(stake_space);

        let stake_minimum_delegation = stake::tools::get_minimum_delegation()?;
        let current_minimum_lamports = minimum_delegation(stake_minimum_delegation);
        if lamports < current_minimum_lamports {
            msg!(
                "Need at least {} lamports for transient stake to meet minimum delegation and rent-exempt requirements, {} provided",
                current_minimum_lamports,
                lamports
            );
            return Err(ProgramError::AccountNotRentExempt);
        }

        let remaining_lamports = validator_stake_account_info
            .lamports()
            .checked_sub(lamports)
            .ok_or(ProgramError::InsufficientFunds)?;
        let required_lamports = minimum_stake_lamports(&meta, stake_minimum_delegation);
        if remaining_lamports < required_lamports {
            msg!("Need at least {} lamports in the stake account after decrease, {} requested, {} is the current possible maximum",
                required_lamports,
                lamports,
                validator_stake_account_info.lamports().checked_sub(required_lamports).ok_or(StakePoolError::CalculationFailure)?
            );
            return Err(ProgramError::InsufficientFunds);
        }

        let (source_stake_account_info, split_lamports) =
            if let Some((ephemeral_stake_seed, ephemeral_stake_account_info)) =
                maybe_ephemeral_stake_seed.zip(maybe_ephemeral_stake_account_info)
            {
                let ephemeral_stake_bump_seed = check_ephemeral_stake_address(
                    program_id,
                    stake_pool_info.key,
                    ephemeral_stake_account_info.key,
                    ephemeral_stake_seed,
                )?;
                let ephemeral_stake_account_signer_seeds: &[&[_]] = &[
                    EPHEMERAL_STAKE_SEED_PREFIX,
                    stake_pool_info.key.as_ref(),
                    &ephemeral_stake_seed.to_le_bytes(),
                    &[ephemeral_stake_bump_seed],
                ];
                create_stake_account(
                    ephemeral_stake_account_info.clone(),
                    ephemeral_stake_account_signer_seeds,
                    stake_space,
                )?;

                // if needed, withdraw rent-exempt reserve for ephemeral account
                if let Some(reserve_stake_info) = maybe_reserve_stake_info {
                    let required_lamports_for_rent_exemption =
                        stake_rent.saturating_sub(ephemeral_stake_account_info.lamports());
                    if required_lamports_for_rent_exemption > 0 {
                        if required_lamports_for_rent_exemption >= reserve_stake_info.lamports() {
                            return Err(StakePoolError::ReserveDepleted.into());
                        }
                        let stake_history_info = maybe_stake_history_info
                            .ok_or(StakePoolError::MissingRequiredSysvar)?;
                        Self::stake_withdraw(
                            stake_pool_info.key,
                            reserve_stake_info.clone(),
                            withdraw_authority_info.clone(),
                            AUTHORITY_WITHDRAW,
                            stake_pool.stake_withdraw_bump_seed,
                            ephemeral_stake_account_info.clone(),
                            clock_info.clone(),
                            stake_history_info.clone(),
                            required_lamports_for_rent_exemption,
                        )?;
                    }
                }

                // split into ephemeral stake account
                Self::stake_split(
                    stake_pool_info.key,
                    validator_stake_account_info.clone(),
                    withdraw_authority_info.clone(),
                    AUTHORITY_WITHDRAW,
                    stake_pool.stake_withdraw_bump_seed,
                    lamports,
                    ephemeral_stake_account_info.clone(),
                )?;

                Self::stake_deactivate(
                    ephemeral_stake_account_info.clone(),
                    clock_info.clone(),
                    withdraw_authority_info.clone(),
                    stake_pool_info.key,
                    AUTHORITY_WITHDRAW,
                    stake_pool.stake_withdraw_bump_seed,
                )?;

                (
                    ephemeral_stake_account_info,
                    ephemeral_stake_account_info.lamports(),
                )
            } else {
                // if no ephemeral account is provided, split everything from the
                // validator stake account, into the transient stake account
                (validator_stake_account_info, lamports)
            };

        let transient_stake_bump_seed = check_transient_stake_address(
            program_id,
            stake_pool_info.key,
            transient_stake_account_info.key,
            &vote_account_address,
            transient_stake_seed,
        )?;

        if u64::from(validator_stake_info.transient_stake_lamports) > 0 {
            let stake_history_info = maybe_stake_history_info.unwrap();
            // transient stake exists, try to merge from the source account,
            // which is always an ephemeral account
            Self::stake_merge(
                stake_pool_info.key,
                source_stake_account_info.clone(),
                withdraw_authority_info.clone(),
                AUTHORITY_WITHDRAW,
                stake_pool.stake_withdraw_bump_seed,
                transient_stake_account_info.clone(),
                clock_info.clone(),
                stake_history_info.clone(),
            )?;
        } else {
            let transient_stake_account_signer_seeds: &[&[_]] = &[
                TRANSIENT_STAKE_SEED_PREFIX,
                vote_account_address.as_ref(),
                stake_pool_info.key.as_ref(),
                &transient_stake_seed.to_le_bytes(),
                &[transient_stake_bump_seed],
            ];

            create_stake_account(
                transient_stake_account_info.clone(),
                transient_stake_account_signer_seeds,
                stake_space,
            )?;

            // if needed, withdraw rent-exempt reserve for transient account
            if let Some(reserve_stake_info) = maybe_reserve_stake_info {
                let required_lamports =
                    stake_rent.saturating_sub(transient_stake_account_info.lamports());
                // in the case of doing a full split from an ephemeral account,
                // the rent-exempt reserve moves over, so no need to fund it from
                // the pool reserve
                if source_stake_account_info.lamports() != split_lamports {
                    let stake_history_info =
                        maybe_stake_history_info.ok_or(StakePoolError::MissingRequiredSysvar)?;
                    if required_lamports >= reserve_stake_info.lamports() {
                        return Err(StakePoolError::ReserveDepleted.into());
                    }
                    if required_lamports > 0 {
                        Self::stake_withdraw(
                            stake_pool_info.key,
                            reserve_stake_info.clone(),
                            withdraw_authority_info.clone(),
                            AUTHORITY_WITHDRAW,
                            stake_pool.stake_withdraw_bump_seed,
                            transient_stake_account_info.clone(),
                            clock_info.clone(),
                            stake_history_info.clone(),
                            required_lamports,
                        )?;
                    }
                }
            }

            // split into transient stake account
            Self::stake_split(
                stake_pool_info.key,
                source_stake_account_info.clone(),
                withdraw_authority_info.clone(),
                AUTHORITY_WITHDRAW,
                stake_pool.stake_withdraw_bump_seed,
                split_lamports,
                transient_stake_account_info.clone(),
            )?;

            // Deactivate transient stake if necessary
            let (_, stake) = get_stake_state(transient_stake_account_info)?;
            if stake.delegation.deactivation_epoch == Epoch::MAX {
                Self::stake_deactivate(
                    transient_stake_account_info.clone(),
                    clock_info.clone(),
                    withdraw_authority_info.clone(),
                    stake_pool_info.key,
                    AUTHORITY_WITHDRAW,
                    stake_pool.stake_withdraw_bump_seed,
                )?;
            }
        }

        validator_stake_info.active_stake_lamports =
            u64::from(validator_stake_info.active_stake_lamports)
                .checked_sub(lamports)
                .ok_or(StakePoolError::CalculationFailure)?
                .into();
        validator_stake_info.transient_stake_lamports =
            transient_stake_account_info.lamports().into();
        validator_stake_info.transient_seed_suffix = transient_stake_seed.into();

        Ok(())
    }

    /// Processes `IncreaseValidatorStake` instruction.
    #[inline(never)] // needed due to stack size violation
    fn process_increase_validator_stake(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        lamports: u64,
        transient_stake_seed: u64,
        maybe_ephemeral_stake_seed: Option<u64>,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let staker_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let validator_list_info = next_account_info(account_info_iter)?;
        let reserve_stake_account_info = next_account_info(account_info_iter)?;
        let maybe_ephemeral_stake_account_info = maybe_ephemeral_stake_seed
            .map(|_| next_account_info(account_info_iter))
            .transpose()?;
        let transient_stake_account_info = next_account_info(account_info_iter)?;
        let validator_stake_account_info = next_account_info(account_info_iter)?;
        let validator_vote_account_info = next_account_info(account_info_iter)?;
        let clock_info = next_account_info(account_info_iter)?;
        let clock = &Clock::from_account_info(clock_info)?;
        let rent = if maybe_ephemeral_stake_seed.is_some() {
            // instruction with ephemeral account doesn't take the rent account
            Rent::get()?
        } else {
            // legacy instruction takes the rent account
            let rent_info = next_account_info(account_info_iter)?;
            Rent::from_account_info(rent_info)?
        };
        let stake_history_info = next_account_info(account_info_iter)?;
        let stake_config_info = next_account_info(account_info_iter)?;
        let system_program_info = next_account_info(account_info_iter)?;
        let stake_program_info = next_account_info(account_info_iter)?;

        check_system_program(system_program_info.key)?;
        check_stake_program(stake_program_info.key)?;
        check_account_owner(stake_pool_info, program_id)?;

        let stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            msg!("Expected valid stake pool");
            return Err(StakePoolError::InvalidState.into());
        }

        stake_pool.check_authority_withdraw(
            withdraw_authority_info.key,
            program_id,
            stake_pool_info.key,
        )?;
        stake_pool.check_staker(staker_info)?;

        if stake_pool.last_update_epoch < clock.epoch {
            return Err(StakePoolError::StakeListAndPoolOutOfDate.into());
        }

        stake_pool.check_validator_list(validator_list_info)?;
        stake_pool.check_reserve_stake(reserve_stake_account_info)?;
        check_account_owner(validator_list_info, program_id)?;

        let mut validator_list_data = validator_list_info.data.borrow_mut();
        let (header, mut validator_list) =
            ValidatorListHeader::deserialize_vec(&mut validator_list_data)?;
        if !header.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        let vote_account_address = validator_vote_account_info.key;

        let maybe_validator_stake_info = validator_list.find_mut::<ValidatorStakeInfo, _>(|x| {
            ValidatorStakeInfo::memcmp_pubkey(x, vote_account_address)
        });
        if maybe_validator_stake_info.is_none() {
            msg!(
                "Vote account {} not found in stake pool",
                vote_account_address
            );
            return Err(StakePoolError::ValidatorNotFound.into());
        }
        let validator_stake_info = maybe_validator_stake_info.unwrap();
        if u64::from(validator_stake_info.transient_stake_lamports) > 0 {
            if maybe_ephemeral_stake_seed.is_none() {
                msg!("Attempting to increase stake on a validator with pending transient stake, use IncreaseAdditionalValidatorStake with the existing seed");
                return Err(StakePoolError::TransientAccountInUse.into());
            }
            if transient_stake_seed != u64::from(validator_stake_info.transient_seed_suffix) {
                msg!(
                    "Transient stake already exists with seed {}, you must use that one",
                    u64::from(validator_stake_info.transient_seed_suffix)
                );
                return Err(ProgramError::InvalidSeeds);
            }
            check_if_stake_activating(
                transient_stake_account_info,
                vote_account_address,
                clock.epoch,
            )?;
        }

        check_validator_stake_account(
            validator_stake_account_info,
            program_id,
            stake_pool_info.key,
            withdraw_authority_info.key,
            vote_account_address,
            validator_stake_info.validator_seed_suffix.into(),
            &stake_pool.lockup,
        )?;

        if validator_stake_info.status != StakeStatus::Active.into() {
            msg!("Validator is marked for removal and no longer allows increases");
            return Err(StakePoolError::ValidatorNotFound.into());
        }

        let stake_space = std::mem::size_of::<stake::state::StakeStateV2>();
        let stake_rent = rent.minimum_balance(stake_space);
        let stake_minimum_delegation = stake::tools::get_minimum_delegation()?;
        let current_minimum_delegation = minimum_delegation(stake_minimum_delegation);
        if lamports < current_minimum_delegation {
            msg!(
                "Need more than {} lamports for transient stake to meet minimum delegation requirement, {} provided",
                current_minimum_delegation,
                lamports
            );
            return Err(ProgramError::Custom(
                stake::error::StakeError::InsufficientDelegation as u32,
            ));
        }

        // the stake account rent exemption is withdrawn after the merge, so
        // to add `lamports` to a validator, we need to create a stake account
        // with `lamports + stake_rent`
        let total_lamports = lamports.saturating_add(stake_rent);

        if reserve_stake_account_info
            .lamports()
            .saturating_sub(total_lamports)
            < stake_rent
        {
            let max_split_amount = reserve_stake_account_info
                .lamports()
                .saturating_sub(stake_rent.saturating_mul(2));
            msg!(
                "Reserve stake does not have enough lamports for increase, maximum amount {}, {} requested",
                max_split_amount,
                lamports
            );
            return Err(ProgramError::InsufficientFunds);
        }

        let source_stake_account_info =
            if let Some((ephemeral_stake_seed, ephemeral_stake_account_info)) =
                maybe_ephemeral_stake_seed.zip(maybe_ephemeral_stake_account_info)
            {
                let ephemeral_stake_bump_seed = check_ephemeral_stake_address(
                    program_id,
                    stake_pool_info.key,
                    ephemeral_stake_account_info.key,
                    ephemeral_stake_seed,
                )?;
                let ephemeral_stake_account_signer_seeds: &[&[_]] = &[
                    EPHEMERAL_STAKE_SEED_PREFIX,
                    stake_pool_info.key.as_ref(),
                    &ephemeral_stake_seed.to_le_bytes(),
                    &[ephemeral_stake_bump_seed],
                ];
                create_stake_account(
                    ephemeral_stake_account_info.clone(),
                    ephemeral_stake_account_signer_seeds,
                    stake_space,
                )?;

                // split into ephemeral stake account
                Self::stake_split(
                    stake_pool_info.key,
                    reserve_stake_account_info.clone(),
                    withdraw_authority_info.clone(),
                    AUTHORITY_WITHDRAW,
                    stake_pool.stake_withdraw_bump_seed,
                    total_lamports,
                    ephemeral_stake_account_info.clone(),
                )?;

                // activate stake to validator
                Self::stake_delegate(
                    ephemeral_stake_account_info.clone(),
                    validator_vote_account_info.clone(),
                    clock_info.clone(),
                    stake_history_info.clone(),
                    stake_config_info.clone(),
                    withdraw_authority_info.clone(),
                    stake_pool_info.key,
                    AUTHORITY_WITHDRAW,
                    stake_pool.stake_withdraw_bump_seed,
                )?;
                ephemeral_stake_account_info
            } else {
                // if no ephemeral account is provided, split everything from the
                // reserve account, into the transient stake account
                reserve_stake_account_info
            };

        let transient_stake_bump_seed = check_transient_stake_address(
            program_id,
            stake_pool_info.key,
            transient_stake_account_info.key,
            vote_account_address,
            transient_stake_seed,
        )?;

        if u64::from(validator_stake_info.transient_stake_lamports) > 0 {
            // transient stake exists, try to merge from the source account,
            // which is always an ephemeral account
            Self::stake_merge(
                stake_pool_info.key,
                source_stake_account_info.clone(),
                withdraw_authority_info.clone(),
                AUTHORITY_WITHDRAW,
                stake_pool.stake_withdraw_bump_seed,
                transient_stake_account_info.clone(),
                clock_info.clone(),
                stake_history_info.clone(),
            )?;
        } else {
            // no transient stake, split
            let transient_stake_account_signer_seeds: &[&[_]] = &[
                TRANSIENT_STAKE_SEED_PREFIX,
                vote_account_address.as_ref(),
                stake_pool_info.key.as_ref(),
                &transient_stake_seed.to_le_bytes(),
                &[transient_stake_bump_seed],
            ];

            create_stake_account(
                transient_stake_account_info.clone(),
                transient_stake_account_signer_seeds,
                stake_space,
            )?;

            // split into transient stake account
            Self::stake_split(
                stake_pool_info.key,
                source_stake_account_info.clone(),
                withdraw_authority_info.clone(),
                AUTHORITY_WITHDRAW,
                stake_pool.stake_withdraw_bump_seed,
                total_lamports,
                transient_stake_account_info.clone(),
            )?;

            // Activate transient stake to validator if necessary
            let stake_state = try_from_slice_unchecked::<stake::state::StakeStateV2>(
                &transient_stake_account_info.data.borrow(),
            )?;
            match stake_state {
                // if it was delegated on or before this epoch, we're good
                stake::state::StakeStateV2::Stake(_, stake, _)
                    if stake.delegation.activation_epoch <= clock.epoch => {}
                // all other situations, delegate!
                _ => {
                    Self::stake_delegate(
                        transient_stake_account_info.clone(),
                        validator_vote_account_info.clone(),
                        clock_info.clone(),
                        stake_history_info.clone(),
                        stake_config_info.clone(),
                        withdraw_authority_info.clone(),
                        stake_pool_info.key,
                        AUTHORITY_WITHDRAW,
                        stake_pool.stake_withdraw_bump_seed,
                    )?;
                }
            }
        }

        validator_stake_info.transient_stake_lamports =
            u64::from(validator_stake_info.transient_stake_lamports)
                .checked_add(total_lamports)
                .ok_or(StakePoolError::CalculationFailure)?
                .into();
        validator_stake_info.transient_seed_suffix = transient_stake_seed.into();

        Ok(())
    }

    /// Process `SetPreferredValidator` instruction
    #[inline(never)] // needed due to stack size violation
    fn process_set_preferred_validator(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        validator_type: PreferredValidatorType,
        vote_account_address: Option<Pubkey>,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let staker_info = next_account_info(account_info_iter)?;
        let validator_list_info = next_account_info(account_info_iter)?;

        check_account_owner(stake_pool_info, program_id)?;
        check_account_owner(validator_list_info, program_id)?;

        let mut stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            msg!("Expected valid stake pool");
            return Err(StakePoolError::InvalidState.into());
        }

        stake_pool.check_staker(staker_info)?;
        stake_pool.check_validator_list(validator_list_info)?;

        let mut validator_list_data = validator_list_info.data.borrow_mut();
        let (header, validator_list) =
            ValidatorListHeader::deserialize_vec(&mut validator_list_data)?;
        if !header.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        if let Some(vote_account_address) = vote_account_address {
            let maybe_validator_stake_info = validator_list.find::<ValidatorStakeInfo, _>(|x| {
                ValidatorStakeInfo::memcmp_pubkey(x, &vote_account_address)
            });
            match maybe_validator_stake_info {
                Some(vsi) => {
                    if vsi.status != StakeStatus::Active.into() {
                        msg!("Validator for {:?} about to be removed, cannot set as preferred deposit account", validator_type);
                        return Err(StakePoolError::InvalidPreferredValidator.into());
                    }
                }
                None => {
                    msg!("Validator for {:?} not present in the stake pool, cannot set as preferred deposit account", validator_type);
                    return Err(StakePoolError::ValidatorNotFound.into());
                }
            }
        }

        match validator_type {
            PreferredValidatorType::Deposit => {
                stake_pool.preferred_deposit_validator_vote_address = vote_account_address
            }
            PreferredValidatorType::Withdraw => {
                stake_pool.preferred_withdraw_validator_vote_address = vote_account_address
            }
        };
        borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)?;
        Ok(())
    }

    /// Processes `UpdateValidatorListBalance` instruction.
    #[inline(always)] // needed to maximize number of validators
    fn process_update_validator_list_balance(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        start_index: u32,
        no_merge: bool,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let validator_list_info = next_account_info(account_info_iter)?;
        let reserve_stake_info = next_account_info(account_info_iter)?;
        let clock_info = next_account_info(account_info_iter)?;
        let clock = &Clock::from_account_info(clock_info)?;
        let stake_history_info = next_account_info(account_info_iter)?;
        let stake_program_info = next_account_info(account_info_iter)?;
        let validator_stake_accounts = account_info_iter.as_slice();

        check_account_owner(stake_pool_info, program_id)?;
        let stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }
        stake_pool.check_validator_list(validator_list_info)?;
        stake_pool.check_authority_withdraw(
            withdraw_authority_info.key,
            program_id,
            stake_pool_info.key,
        )?;
        stake_pool.check_reserve_stake(reserve_stake_info)?;
        check_stake_program(stake_program_info.key)?;

        // If rewards are being distributed, abort
        let epoch_rewards = EpochRewards::get()?;
        if epoch_rewards.active {
            return Err(StakePoolError::EpochRewardDistributionInProgress.into());
        }

        if validator_stake_accounts
            .len()
            .checked_rem(2)
            .ok_or(StakePoolError::CalculationFailure)?
            != 0
        {
            msg!("Odd number of validator stake accounts passed in, should be pairs of validator stake and transient stake accounts");
            return Err(StakePoolError::UnexpectedValidatorListAccountSize.into());
        }

        check_account_owner(validator_list_info, program_id)?;
        let mut validator_list_data = validator_list_info.data.borrow_mut();
        let (validator_list_header, mut big_vec) =
            ValidatorListHeader::deserialize_vec(&mut validator_list_data)?;
        let validator_slice = ValidatorListHeader::deserialize_mut_slice(
            &mut big_vec,
            start_index as usize,
            validator_stake_accounts.len() / 2,
        )?;

        if !validator_list_header.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        let validator_iter = &mut validator_slice
            .iter_mut()
            .zip(validator_stake_accounts.chunks_exact(2));
        for (validator_stake_record, validator_stakes) in validator_iter {
            // chunks_exact means that we always get 2 elements, making this safe
            let validator_stake_info = validator_stakes
                .first()
                .ok_or(ProgramError::InvalidInstructionData)?;
            let transient_stake_info = validator_stakes
                .last()
                .ok_or(ProgramError::InvalidInstructionData)?;
            if check_validator_stake_address(
                program_id,
                stake_pool_info.key,
                validator_stake_info.key,
                &validator_stake_record.vote_account_address,
                NonZeroU32::new(validator_stake_record.validator_seed_suffix.into()),
            )
            .is_err()
            {
                continue;
            };
            if check_transient_stake_address(
                program_id,
                stake_pool_info.key,
                transient_stake_info.key,
                &validator_stake_record.vote_account_address,
                validator_stake_record.transient_seed_suffix.into(),
            )
            .is_err()
            {
                continue;
            };

            let mut active_stake_lamports = 0;
            let mut transient_stake_lamports = 0;
            let validator_stake_state = try_from_slice_unchecked::<stake::state::StakeStateV2>(
                &validator_stake_info.data.borrow(),
            )
            .ok();
            let transient_stake_state = try_from_slice_unchecked::<stake::state::StakeStateV2>(
                &transient_stake_info.data.borrow(),
            )
            .ok();

            // Possible merge situations for transient stake
            //  * active -> merge into validator stake
            //  * activating -> nothing, just account its lamports
            //  * deactivating -> nothing, just account its lamports
            //  * inactive -> merge into reserve stake
            //  * not a stake -> ignore
            if validator_stake_record.transient_stake_lamports != 0.into() {
                match transient_stake_state {
                    Some(stake::state::StakeStateV2::Initialized(meta)) => {
                        if stake_is_usable_by_pool(
                            &meta,
                            withdraw_authority_info.key,
                            &stake_pool.lockup,
                        ) {
                            if no_merge {
                                transient_stake_lamports = transient_stake_info.lamports();
                            } else {
                                // merge into reserve
                                Self::stake_merge(
                                    stake_pool_info.key,
                                    transient_stake_info.clone(),
                                    withdraw_authority_info.clone(),
                                    AUTHORITY_WITHDRAW,
                                    stake_pool.stake_withdraw_bump_seed,
                                    reserve_stake_info.clone(),
                                    clock_info.clone(),
                                    stake_history_info.clone(),
                                )?;
                                validator_stake_record.status.remove_transient_stake()?;
                            }
                        }
                    }
                    Some(stake::state::StakeStateV2::Stake(meta, stake, _)) => {
                        if stake_is_usable_by_pool(
                            &meta,
                            withdraw_authority_info.key,
                            &stake_pool.lockup,
                        ) {
                            if !no_merge {
                                if stake_is_inactive_without_history(&stake, clock.epoch) {
                                    // deactivated, merge into reserve
                                    Self::stake_merge(
                                        stake_pool_info.key,
                                        transient_stake_info.clone(),
                                        withdraw_authority_info.clone(),
                                        AUTHORITY_WITHDRAW,
                                        stake_pool.stake_withdraw_bump_seed,
                                        reserve_stake_info.clone(),
                                        clock_info.clone(),
                                        stake_history_info.clone(),
                                    )?;
                                    validator_stake_record.status.remove_transient_stake()?;
                                } else if validator_stake_record.status.try_into()
                                    == Ok(StakeStatus::Active)
                                {
                                    if stake.delegation.activation_epoch < clock.epoch {
                                        if let Some(stake::state::StakeStateV2::Stake(
                                            _,
                                            validator_stake,
                                            _,
                                        )) = validator_stake_state
                                        {
                                            if validator_stake.delegation.activation_epoch
                                                < clock.epoch
                                            {
                                                Self::stake_merge(
                                                    stake_pool_info.key,
                                                    transient_stake_info.clone(),
                                                    withdraw_authority_info.clone(),
                                                    AUTHORITY_WITHDRAW,
                                                    stake_pool.stake_withdraw_bump_seed,
                                                    validator_stake_info.clone(),
                                                    clock_info.clone(),
                                                    stake_history_info.clone(),
                                                )?;
                                            } else {
                                                msg!("Stake activating or just active, not ready to merge");
                                            }
                                        } else {
                                            msg!("Transient stake is activating or active, but validator stake is not, need to add the validator stake account on {} back into the stake pool", stake.delegation.voter_pubkey);
                                        }
                                    } else {
                                        msg!("Transient stake not ready to be merged anywhere");
                                    }
                                } else if stake.delegation.deactivation_epoch == Epoch::MAX {
                                    msg!("Transient stake is activating or active, deactivating.");
                                    Self::stake_deactivate(
                                        transient_stake_info.clone(),
                                        clock_info.clone(),
                                        withdraw_authority_info.clone(),
                                        stake_pool_info.key,
                                        AUTHORITY_WITHDRAW,
                                        stake_pool.stake_withdraw_bump_seed,
                                    )?;
                                }
                            }
                            transient_stake_lamports = transient_stake_info.lamports();
                        }
                    }
                    None
                    | Some(stake::state::StakeStateV2::Uninitialized)
                    | Some(stake::state::StakeStateV2::RewardsPool) => {} // do nothing
                }
            }
            // Status for validator stake
            //  * active -> do everything
            //  * any other state / not a stake -> error state, but account for transient
            //    stake
            let validator_stake_state = try_from_slice_unchecked::<stake::state::StakeStateV2>(
                &validator_stake_info.data.borrow(),
            )
            .ok();
            match validator_stake_state {
                Some(stake::state::StakeStateV2::Stake(meta, stake, _))
                    if stake_is_usable_by_pool(
                        &meta,
                        withdraw_authority_info.key,
                        &stake_pool.lockup,
                    ) =>
                {
                    let additional_lamports = validator_stake_info
                        .lamports()
                        .saturating_sub(stake.delegation.stake)
                        .saturating_sub(meta.rent_exempt_reserve);
                    // withdraw any extra lamports back to the reserve
                    if additional_lamports > 0 {
                        Self::stake_withdraw(
                            stake_pool_info.key,
                            validator_stake_info.clone(),
                            withdraw_authority_info.clone(),
                            AUTHORITY_WITHDRAW,
                            stake_pool.stake_withdraw_bump_seed,
                            reserve_stake_info.clone(),
                            clock_info.clone(),
                            stake_history_info.clone(),
                            additional_lamports,
                        )?;
                    }
                    match validator_stake_record.status.try_into()? {
                        StakeStatus::Active => {
                            active_stake_lamports = validator_stake_info.lamports();
                        }
                        StakeStatus::DeactivatingValidator | StakeStatus::DeactivatingAll => {
                            if no_merge {
                                active_stake_lamports = validator_stake_info.lamports();
                            } else if stake_is_inactive_without_history(&stake, clock.epoch) {
                                // Validator was removed through normal means.
                                // Absorb the lamports into the reserve.
                                Self::stake_merge(
                                    stake_pool_info.key,
                                    validator_stake_info.clone(),
                                    withdraw_authority_info.clone(),
                                    AUTHORITY_WITHDRAW,
                                    stake_pool.stake_withdraw_bump_seed,
                                    reserve_stake_info.clone(),
                                    clock_info.clone(),
                                    stake_history_info.clone(),
                                )?;
                                validator_stake_record.status.remove_validator_stake()?;
                            } else {
                                active_stake_lamports = validator_stake_info.lamports();
                            }
                        }
                        StakeStatus::DeactivatingTransient | StakeStatus::ReadyForRemoval => {
                            msg!("Validator stake account no longer part of the pool, ignoring");
                        }
                    }
                }
                Some(stake::state::StakeStateV2::Initialized(meta))
                    if stake_is_usable_by_pool(
                        &meta,
                        withdraw_authority_info.key,
                        &stake_pool.lockup,
                    ) =>
                {
                    // If a validator stake is `Initialized`, the validator could
                    // have been destaked during a cluster restart or removed through
                    // normal means. Either way, absorb those lamports into the reserve.
                    // The transient stake was likely absorbed into the reserve earlier.
                    Self::stake_merge(
                        stake_pool_info.key,
                        validator_stake_info.clone(),
                        withdraw_authority_info.clone(),
                        AUTHORITY_WITHDRAW,
                        stake_pool.stake_withdraw_bump_seed,
                        reserve_stake_info.clone(),
                        clock_info.clone(),
                        stake_history_info.clone(),
                    )?;
                    if transient_stake_lamports != 0 {
                        validator_stake_record.status = StakeStatus::DeactivatingTransient.into();
                    } else {
                        validator_stake_record.status = StakeStatus::ReadyForRemoval.into();
                    }
                }
                Some(stake::state::StakeStateV2::Stake(_, _, _))
                | Some(stake::state::StakeStateV2::Initialized(_))
                | Some(stake::state::StakeStateV2::Uninitialized)
                | Some(stake::state::StakeStateV2::RewardsPool)
                | None => {
                    msg!("Validator stake account no longer part of the pool, ignoring");
                }
            }

            validator_stake_record.last_update_epoch = clock.epoch.into();
            validator_stake_record.active_stake_lamports = active_stake_lamports.into();
            validator_stake_record.transient_stake_lamports = transient_stake_lamports.into();
        }

        Ok(())
    }

    /// Processes `UpdateStakePoolBalance` instruction.
    #[inline(always)] // needed to optimize number of validators
    fn process_update_stake_pool_balance(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let withdraw_info = next_account_info(account_info_iter)?;
        let validator_list_info = next_account_info(account_info_iter)?;
        let reserve_stake_info = next_account_info(account_info_iter)?;
        let manager_fee_info = next_account_info(account_info_iter)?;
        let pool_mint_info = next_account_info(account_info_iter)?;
        let token_program_info = next_account_info(account_info_iter)?;
        let clock = Clock::get()?;

        check_account_owner(stake_pool_info, program_id)?;
        let mut stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }
        stake_pool.check_mint(pool_mint_info)?;
        stake_pool.check_authority_withdraw(withdraw_info.key, program_id, stake_pool_info.key)?;
        stake_pool.check_reserve_stake(reserve_stake_info)?;
        if stake_pool.manager_fee_account != *manager_fee_info.key {
            return Err(StakePoolError::InvalidFeeAccount.into());
        }

        if *validator_list_info.key != stake_pool.validator_list {
            return Err(StakePoolError::InvalidValidatorStakeList.into());
        }
        if stake_pool.token_program_id != *token_program_info.key {
            return Err(ProgramError::IncorrectProgramId);
        }

        check_account_owner(validator_list_info, program_id)?;
        let mut validator_list_data = validator_list_info.data.borrow_mut();
        let (header, validator_list) =
            ValidatorListHeader::deserialize_vec(&mut validator_list_data)?;
        if !header.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        let previous_lamports = stake_pool.total_lamports;
        let previous_pool_token_supply = stake_pool.pool_token_supply;
        let reserve_stake = try_from_slice_unchecked::<stake::state::StakeStateV2>(
            &reserve_stake_info.data.borrow(),
        )?;
        let mut total_lamports =
            if let stake::state::StakeStateV2::Initialized(meta) = reserve_stake {
                reserve_stake_info
                    .lamports()
                    .checked_sub(minimum_reserve_lamports(&meta))
                    .ok_or(StakePoolError::CalculationFailure)?
            } else {
                msg!("Reserve stake account in unknown state, aborting");
                return Err(StakePoolError::WrongStakeStake.into());
            };
        for validator_stake_record in validator_list
            .deserialize_slice::<ValidatorStakeInfo>(0, validator_list.len() as usize)?
        {
            if u64::from(validator_stake_record.last_update_epoch) < clock.epoch {
                return Err(StakePoolError::StakeListOutOfDate.into());
            }
            total_lamports = total_lamports
                .checked_add(validator_stake_record.stake_lamports()?)
                .ok_or(StakePoolError::CalculationFailure)?;
        }

        let reward_lamports = total_lamports.saturating_sub(previous_lamports);

        // If the manager fee info is invalid, they don't deserve to receive the fee.
        let fee = if stake_pool.check_manager_fee_info(manager_fee_info).is_ok() {
            stake_pool
                .calc_epoch_fee_amount(reward_lamports)
                .ok_or(StakePoolError::CalculationFailure)?
        } else {
            0
        };

        if fee > 0 {
            Self::token_mint_to(
                stake_pool_info.key,
                token_program_info.clone(),
                pool_mint_info.clone(),
                manager_fee_info.clone(),
                withdraw_info.clone(),
                AUTHORITY_WITHDRAW,
                stake_pool.stake_withdraw_bump_seed,
                fee,
            )?;
        }

        if stake_pool.last_update_epoch < clock.epoch {
            if let Some(fee) = stake_pool.next_epoch_fee.get() {
                stake_pool.epoch_fee = *fee;
            }
            stake_pool.next_epoch_fee.update_epoch();

            if let Some(fee) = stake_pool.next_stake_withdrawal_fee.get() {
                stake_pool.stake_withdrawal_fee = *fee;
            }
            stake_pool.next_stake_withdrawal_fee.update_epoch();

            if let Some(fee) = stake_pool.next_sol_withdrawal_fee.get() {
                stake_pool.sol_withdrawal_fee = *fee;
            }
            stake_pool.next_sol_withdrawal_fee.update_epoch();

            stake_pool.last_update_epoch = clock.epoch;
            stake_pool.last_epoch_total_lamports = previous_lamports;
            stake_pool.last_epoch_pool_token_supply = previous_pool_token_supply;
        }
        stake_pool.total_lamports = total_lamports;

        let pool_mint_data = pool_mint_info.try_borrow_data()?;
        let pool_mint = StateWithExtensions::<Mint>::unpack(&pool_mint_data)?;
        stake_pool.pool_token_supply = pool_mint.base.supply;

        borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)?;

        Ok(())
    }

    /// Processes the `CleanupRemovedValidatorEntries` instruction
    #[inline(never)] // needed to avoid stack size violation
    fn process_cleanup_removed_validator_entries(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let validator_list_info = next_account_info(account_info_iter)?;

        check_account_owner(stake_pool_info, program_id)?;
        let stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }
        stake_pool.check_validator_list(validator_list_info)?;

        check_account_owner(validator_list_info, program_id)?;
        let mut validator_list_data = validator_list_info.data.borrow_mut();
        let (header, mut validator_list) =
            ValidatorListHeader::deserialize_vec(&mut validator_list_data)?;
        if !header.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        validator_list.retain::<ValidatorStakeInfo, _>(|x| !ValidatorStakeInfo::is_removed(x))?;

        if stake_pool_info.is_writable {
            msg!("Checking preferred validators");
            let mut stake_pool =
                try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;

            // Check and reset preferred validators if they don't exist or aren't active
            // Check preferred deposit validator
            if let Some(preferred_deposit) = stake_pool.preferred_deposit_validator_vote_address {
                let maybe_validator = validator_list.find::<ValidatorStakeInfo, _>(|x| {
                    ValidatorStakeInfo::memcmp_pubkey(x, &preferred_deposit)
                });

                let should_reset = match maybe_validator {
                    Some(validator) => {
                        // Check if validator status is not Active
                        match validator.status.try_into() {
                            Ok(StakeStatus::Active) => false, // Valid, keep it
                            _ => true,                        // Not active, reset it
                        }
                    }
                    None => true, // Not found in list, reset it
                };

                if should_reset {
                    msg!(
                        "Preferred deposit validator {} not found or not active, resetting",
                        preferred_deposit
                    );
                    stake_pool.preferred_deposit_validator_vote_address = None;
                }
            }

            // Check preferred withdrawal validator
            if let Some(preferred_withdraw) = stake_pool.preferred_withdraw_validator_vote_address {
                let maybe_validator = validator_list.find::<ValidatorStakeInfo, _>(|x| {
                    ValidatorStakeInfo::memcmp_pubkey(x, &preferred_withdraw)
                });

                let should_reset = match maybe_validator {
                    Some(validator) => {
                        // Check if validator status is not Active
                        match validator.status.try_into() {
                            Ok(StakeStatus::Active) => false, // Valid, keep it
                            _ => true,                        // Not active, reset it
                        }
                    }
                    None => true, // Not found in list, reset it
                };

                if should_reset {
                    msg!(
                        "Preferred withdrawal validator {} not found or not active, resetting",
                        preferred_withdraw
                    );
                    stake_pool.preferred_withdraw_validator_vote_address = None;
                }
            }

            // Save the updated stake pool state
            borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)?;
        }

        Ok(())
    }

    /// Processes [`DepositStake`](enum.Instruction.html).
    #[inline(never)] // needed to avoid stack size violation
    fn process_deposit_stake(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        minimum_pool_tokens_out: Option<u64>,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let validator_list_info = next_account_info(account_info_iter)?;
        let stake_deposit_authority_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let stake_info = next_account_info(account_info_iter)?;
        let validator_stake_account_info = next_account_info(account_info_iter)?;
        let reserve_stake_account_info = next_account_info(account_info_iter)?;
        let dest_user_pool_info = next_account_info(account_info_iter)?;
        let manager_fee_info = next_account_info(account_info_iter)?;
        let referrer_fee_info = next_account_info(account_info_iter)?;
        let pool_mint_info = next_account_info(account_info_iter)?;
        let clock_info = next_account_info(account_info_iter)?;
        let clock = &Clock::from_account_info(clock_info)?;
        let stake_history_info = next_account_info(account_info_iter)?;
        let token_program_info = next_account_info(account_info_iter)?;
        let stake_program_info = next_account_info(account_info_iter)?;

        check_stake_program(stake_program_info.key)?;

        check_account_owner(stake_pool_info, program_id)?;
        let mut stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        stake_pool.check_authority_withdraw(
            withdraw_authority_info.key,
            program_id,
            stake_pool_info.key,
        )?;
        stake_pool.check_stake_deposit_authority(stake_deposit_authority_info.key)?;
        stake_pool.check_mint(pool_mint_info)?;
        stake_pool.check_validator_list(validator_list_info)?;
        stake_pool.check_reserve_stake(reserve_stake_account_info)?;

        if stake_pool.token_program_id != *token_program_info.key {
            return Err(ProgramError::IncorrectProgramId);
        }

        if stake_pool.manager_fee_account != *manager_fee_info.key {
            return Err(StakePoolError::InvalidFeeAccount.into());
        }
        // There is no bypass if the manager fee account is invalid. Deposits
        // don't hold user funds hostage, so if the fee account is invalid, users
        // cannot deposit in the pool.  Let it fail here!

        if stake_pool.last_update_epoch < clock.epoch {
            return Err(StakePoolError::StakeListAndPoolOutOfDate.into());
        }

        check_account_owner(validator_list_info, program_id)?;
        let mut validator_list_data = validator_list_info.data.borrow_mut();
        let (header, mut validator_list) =
            ValidatorListHeader::deserialize_vec(&mut validator_list_data)?;
        if !header.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        let (_, validator_stake) = get_stake_state(validator_stake_account_info)?;
        let pre_all_validator_lamports = validator_stake_account_info.lamports();
        let vote_account_address = validator_stake.delegation.voter_pubkey;
        if let Some(preferred_deposit) = stake_pool.preferred_deposit_validator_vote_address {
            if preferred_deposit != vote_account_address {
                msg!(
                    "Incorrect deposit address, expected {}, received {}",
                    preferred_deposit,
                    vote_account_address
                );
                return Err(StakePoolError::IncorrectDepositVoteAddress.into());
            }
        }

        let validator_stake_info = validator_list
            .find_mut::<ValidatorStakeInfo, _>(|x| {
                ValidatorStakeInfo::memcmp_pubkey(x, &vote_account_address)
            })
            .ok_or(StakePoolError::ValidatorNotFound)?;
        check_validator_stake_address(
            program_id,
            stake_pool_info.key,
            validator_stake_account_info.key,
            &vote_account_address,
            NonZeroU32::new(validator_stake_info.validator_seed_suffix.into()),
        )?;

        if validator_stake_info.status != StakeStatus::Active.into() {
            msg!("Validator is marked for removal and no longer accepting deposits");
            return Err(StakePoolError::ValidatorNotFound.into());
        }

        msg!("Stake pre merge {}", validator_stake.delegation.stake);

        let (stake_deposit_authority_program_address, deposit_bump_seed) =
            find_deposit_authority_program_address(program_id, stake_pool_info.key);
        if *stake_deposit_authority_info.key == stake_deposit_authority_program_address {
            Self::stake_authorize_signed(
                stake_pool_info.key,
                stake_info.clone(),
                stake_deposit_authority_info.clone(),
                AUTHORITY_DEPOSIT,
                deposit_bump_seed,
                withdraw_authority_info.key,
                clock_info.clone(),
            )?;
        } else {
            Self::stake_authorize(
                stake_info.clone(),
                stake_deposit_authority_info.clone(),
                withdraw_authority_info.key,
                clock_info.clone(),
            )?;
        }

        Self::stake_merge(
            stake_pool_info.key,
            stake_info.clone(),
            withdraw_authority_info.clone(),
            AUTHORITY_WITHDRAW,
            stake_pool.stake_withdraw_bump_seed,
            validator_stake_account_info.clone(),
            clock_info.clone(),
            stake_history_info.clone(),
        )?;

        let (_, post_validator_stake) = get_stake_state(validator_stake_account_info)?;
        let post_all_validator_lamports = validator_stake_account_info.lamports();
        msg!("Stake post merge {}", post_validator_stake.delegation.stake);

        let total_deposit_lamports = post_all_validator_lamports
            .checked_sub(pre_all_validator_lamports)
            .ok_or(StakePoolError::CalculationFailure)?;
        let stake_deposit_lamports = post_validator_stake
            .delegation
            .stake
            .checked_sub(validator_stake.delegation.stake)
            .ok_or(StakePoolError::CalculationFailure)?;
        let sol_deposit_lamports = total_deposit_lamports
            .checked_sub(stake_deposit_lamports)
            .ok_or(StakePoolError::CalculationFailure)?;

        let new_pool_tokens = stake_pool
            .calc_pool_tokens_for_deposit(total_deposit_lamports)
            .ok_or(StakePoolError::CalculationFailure)?;
        let new_pool_tokens_from_stake = stake_pool
            .calc_pool_tokens_for_deposit(stake_deposit_lamports)
            .ok_or(StakePoolError::CalculationFailure)?;
        let new_pool_tokens_from_sol = new_pool_tokens
            .checked_sub(new_pool_tokens_from_stake)
            .ok_or(StakePoolError::CalculationFailure)?;

        let stake_deposit_fee = stake_pool
            .calc_pool_tokens_stake_deposit_fee(new_pool_tokens_from_stake)
            .ok_or(StakePoolError::CalculationFailure)?;
        let sol_deposit_fee = stake_pool
            .calc_pool_tokens_sol_deposit_fee(new_pool_tokens_from_sol)
            .ok_or(StakePoolError::CalculationFailure)?;

        let total_fee = stake_deposit_fee
            .checked_add(sol_deposit_fee)
            .ok_or(StakePoolError::CalculationFailure)?;
        let pool_tokens_user = new_pool_tokens
            .checked_sub(total_fee)
            .ok_or(StakePoolError::CalculationFailure)?;

        let pool_tokens_referral_fee = stake_pool
            .calc_pool_tokens_stake_referral_fee(total_fee)
            .ok_or(StakePoolError::CalculationFailure)?;

        let pool_tokens_manager_deposit_fee = total_fee
            .checked_sub(pool_tokens_referral_fee)
            .ok_or(StakePoolError::CalculationFailure)?;

        if pool_tokens_user
            .saturating_add(pool_tokens_manager_deposit_fee)
            .saturating_add(pool_tokens_referral_fee)
            != new_pool_tokens
        {
            return Err(StakePoolError::CalculationFailure.into());
        }

        if pool_tokens_user == 0 {
            return Err(StakePoolError::DepositTooSmall.into());
        }

        if let Some(minimum_pool_tokens_out) = minimum_pool_tokens_out {
            if pool_tokens_user < minimum_pool_tokens_out {
                return Err(StakePoolError::ExceededSlippage.into());
            }
        }

        Self::token_mint_to(
            stake_pool_info.key,
            token_program_info.clone(),
            pool_mint_info.clone(),
            dest_user_pool_info.clone(),
            withdraw_authority_info.clone(),
            AUTHORITY_WITHDRAW,
            stake_pool.stake_withdraw_bump_seed,
            pool_tokens_user,
        )?;
        if pool_tokens_manager_deposit_fee > 0 {
            Self::token_mint_to(
                stake_pool_info.key,
                token_program_info.clone(),
                pool_mint_info.clone(),
                manager_fee_info.clone(),
                withdraw_authority_info.clone(),
                AUTHORITY_WITHDRAW,
                stake_pool.stake_withdraw_bump_seed,
                pool_tokens_manager_deposit_fee,
            )?;
        }
        if pool_tokens_referral_fee > 0 {
            Self::token_mint_to(
                stake_pool_info.key,
                token_program_info.clone(),
                pool_mint_info.clone(),
                referrer_fee_info.clone(),
                withdraw_authority_info.clone(),
                AUTHORITY_WITHDRAW,
                stake_pool.stake_withdraw_bump_seed,
                pool_tokens_referral_fee,
            )?;
        }

        // withdraw additional lamports to the reserve
        if sol_deposit_lamports > 0 {
            Self::stake_withdraw(
                stake_pool_info.key,
                validator_stake_account_info.clone(),
                withdraw_authority_info.clone(),
                AUTHORITY_WITHDRAW,
                stake_pool.stake_withdraw_bump_seed,
                reserve_stake_account_info.clone(),
                clock_info.clone(),
                stake_history_info.clone(),
                sol_deposit_lamports,
            )?;
        }

        stake_pool.pool_token_supply = stake_pool
            .pool_token_supply
            .checked_add(new_pool_tokens)
            .ok_or(StakePoolError::CalculationFailure)?;
        // We treat the extra lamports as though they were
        // transferred directly to the reserve stake account.
        stake_pool.total_lamports = stake_pool
            .total_lamports
            .checked_add(total_deposit_lamports)
            .ok_or(StakePoolError::CalculationFailure)?;
        borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)?;

        validator_stake_info.active_stake_lamports = validator_stake_account_info.lamports().into();

        Ok(())
    }

    /// Processes [`DepositWsolWithSession`](enum.Instruction.html).
    #[inline(never)]
    fn process_deposit_wsol_with_session(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        deposit_lamports: u64,
        minimum_pool_tokens_out: Option<u64>,
    ) -> ProgramResult {
        use fogo_sessions_sdk::token::instruction::transfer_checked;
        use fogo_sessions_sdk::{session::Session, token::PROGRAM_SIGNER_SEED};
        use solana_program::program_pack::Pack;
        use spl_associated_token_account::tools::account::create_pda_account;

        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let reserve_stake_account_info = next_account_info(account_info_iter)?;
        let signer_or_session_info = next_account_info(account_info_iter)?;
        let dest_user_pool_info = next_account_info(account_info_iter)?;
        let manager_fee_info = next_account_info(account_info_iter)?;
        let referrer_fee_info = next_account_info(account_info_iter)?;
        let pool_mint_info = next_account_info(account_info_iter)?;
        let system_program_info = next_account_info(account_info_iter)?;
        let token_program_info = next_account_info(account_info_iter)?;

        // wsol-specific accounts
        let wsol_mint_info = next_account_info(account_info_iter)?;
        let wsol_token_info = next_account_info(account_info_iter)?;
        let wsol_transient_info = next_account_info(account_info_iter)?;
        let program_signer_info = next_account_info(account_info_iter)?;
        let payer_info = next_account_info(account_info_iter)?;
        let user_wallet_info = next_account_info(account_info_iter)?;

        let sol_deposit_authority_info = next_account_info(account_info_iter);

        if *wsol_mint_info.key != spl_token::native_mint::id() {
            msg!("`wsol_mint` is not the native SOL mint");
            return Err(ProgramError::InvalidAccountData);
        }

        if *wsol_mint_info.owner != *token_program_info.key {
            msg!("`wsol_mint` is not owned by the token program");
            return Err(ProgramError::InvalidAccountData);
        }

        if *wsol_token_info.owner != *token_program_info.key {
            msg!("`wsol_token` is not owned by the token program");
            return Err(ProgramError::InvalidAccountData);
        }

        let user_pubkey =
            Session::extract_user_from_signer_or_session(signer_or_session_info, program_id)?;

        // Verify wsol_token_info is a valid wSOL token account owned by the user
        let wsol_token_data = spl_token::state::Account::unpack(&wsol_token_info.data.borrow())?;
        if wsol_token_data.mint != spl_token::native_mint::id() {
            msg!("`wsol_token` is not a wSOL token account");
            return Err(ProgramError::InvalidAccountData);
        }
        if wsol_token_data.owner != user_pubkey {
            msg!("`wsol_token` is not owned by the session user");
            return Err(ProgramError::InvalidAccountData);
        }

        const TRANSIENT_SEED: &[u8] = b"transient_wsol";

        let (expected_program_signer, program_signer_bump) =
            Pubkey::find_program_address(&[PROGRAM_SIGNER_SEED], program_id);

        if *program_signer_info.key != expected_program_signer {
            msg!("`program_signer` does not match expected address");
            return Err(ProgramError::InvalidSeeds);
        }

        let (expected_transient_pda, transient_bump) =
            Pubkey::find_program_address(&[TRANSIENT_SEED, user_pubkey.as_ref()], program_id);

        if *wsol_transient_info.key != expected_transient_pda {
            msg!("`wsol_transient` does not match expected address");
            return Err(ProgramError::InvalidSeeds);
        }

        let program_signer_seeds: &[&[u8]] = &[PROGRAM_SIGNER_SEED, &[program_signer_bump]];
        let transient_seeds: &[&[u8]] = &[TRANSIENT_SEED, user_pubkey.as_ref(), &[transient_bump]];

        let rent = Rent::get()?;

        // Create the transient wSOL account
        create_pda_account(
            payer_info,
            &rent,
            spl_token::state::Account::LEN,
            token_program_info.key,
            system_program_info,
            wsol_transient_info,
            transient_seeds,
        )?;

        invoke(
            &spl_token::instruction::initialize_account3(
                token_program_info.key,
                wsol_transient_info.key,
                wsol_mint_info.key,
                program_signer_info.key,
            )?,
            &[wsol_transient_info.clone(), wsol_mint_info.clone()],
        )?;

        // Transfer wSOL from user to transient account and unwrap to SOL
        invoke_signed(
            &transfer_checked(
                token_program_info.key,
                wsol_token_info.key,
                wsol_mint_info.key,
                wsol_transient_info.key,
                signer_or_session_info.key,
                Some(program_signer_info.key),
                deposit_lamports,
                native_mint::DECIMALS,
            )?,
            &[
                token_program_info.clone(),
                wsol_token_info.clone(),
                wsol_mint_info.clone(),
                wsol_transient_info.clone(),
                signer_or_session_info.clone(),
                program_signer_info.clone(),
            ],
            &[program_signer_seeds],
        )?;

        // Close the transient wSOL account to unwrap to SOL
        invoke_signed(
            &spl_token::instruction::close_account(
                token_program_info.key,
                wsol_transient_info.key,
                program_signer_info.key,
                program_signer_info.key,
                &[],
            )?,
            &[wsol_transient_info.clone(), program_signer_info.clone()],
            &[program_signer_seeds],
        )?;

        // Refund transient wSOL rent to payer
        let rent_lamports = rent.minimum_balance(spl_token::state::Account::LEN).max(1);

        invoke_signed(
            &system_instruction::transfer(program_signer_info.key, payer_info.key, rent_lamports),
            &[
                system_program_info.clone(),
                program_signer_info.clone(),
                payer_info.clone(),
            ],
            &[program_signer_seeds],
        )?;

        // Verify dest_user_pool_info is the correct ATA for user_wallet
        let expected_ata =
            spl_associated_token_account::get_associated_token_address_with_program_id(
                user_wallet_info.key,
                pool_mint_info.key,
                token_program_info.key,
            );
        if *dest_user_pool_info.key != expected_ata {
            msg!("dest_user_pool is not the ATA for user_wallet");
            return Err(ProgramError::InvalidAccountData);
        }

        let ata_creation_cost = rent
            .minimum_balance(spl_token::state::Account::LEN)
            .saturating_sub(dest_user_pool_info.lamports());

        if deposit_lamports < ata_creation_cost {
            msg!("Deposit too small to cover ATA rent");
            return Err(StakePoolError::DepositTooSmall.into());
        }

        if ata_creation_cost > 0 {
            invoke_signed(
                &spl_associated_token_account::instruction::create_associated_token_account_idempotent(
                    program_signer_info.key,
                    user_wallet_info.key,
                    pool_mint_info.key,
                    token_program_info.key,
                ),
                &[
                    program_signer_info.clone(),
                    dest_user_pool_info.clone(),
                    user_wallet_info.clone(),
                    pool_mint_info.clone(),
                    system_program_info.clone(),
                    token_program_info.clone(),
                ],
                &[program_signer_seeds],
            )?;
        }

        let effective_deposit = deposit_lamports - ata_creation_cost;

        invoke_signed(
            &system_instruction::transfer(
                program_signer_info.key,
                reserve_stake_account_info.key,
                effective_deposit,
            ),
            &[
                system_program_info.clone(),
                program_signer_info.clone(),
                reserve_stake_account_info.clone(),
            ],
            &[program_signer_seeds],
        )?;

        let mut new_accounts = vec![
            stake_pool_info.clone(),
            withdraw_authority_info.clone(),
            reserve_stake_account_info.clone(),
            signer_or_session_info.clone(),
            dest_user_pool_info.clone(),
            manager_fee_info.clone(),
            referrer_fee_info.clone(),
            pool_mint_info.clone(),
            system_program_info.clone(),
            token_program_info.clone(),
        ];

        if let Ok(sol_deposit_authority_info) = sol_deposit_authority_info {
            new_accounts.push(sol_deposit_authority_info.clone());
        }

        Self::process_deposit_sol(
            program_id,
            &new_accounts,
            effective_deposit,
            minimum_pool_tokens_out,
            // the SOL transfer has already been done above
            true,
        )
    }

    /// Processes [`DepositSol`](enum.Instruction.html).
    #[inline(never)] // needed to avoid stack size violation
    fn process_deposit_sol(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        deposit_lamports: u64,
        minimum_pool_tokens_out: Option<u64>,
        is_wsol_path: bool,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let reserve_stake_account_info = next_account_info(account_info_iter)?;
        let from_user_lamports_info = next_account_info(account_info_iter)?;
        let dest_user_pool_info = next_account_info(account_info_iter)?;
        let manager_fee_info = next_account_info(account_info_iter)?;
        let referrer_fee_info = next_account_info(account_info_iter)?;
        let pool_mint_info = next_account_info(account_info_iter)?;
        let system_program_info = next_account_info(account_info_iter)?;
        let token_program_info = next_account_info(account_info_iter)?;
        let sol_deposit_authority_info = next_account_info(account_info_iter);

        let clock = Clock::get()?;

        check_account_owner(stake_pool_info, program_id)?;
        let mut stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        stake_pool.check_authority_withdraw(
            withdraw_authority_info.key,
            program_id,
            stake_pool_info.key,
        )?;
        stake_pool.check_sol_deposit_authority(sol_deposit_authority_info)?;
        stake_pool.check_mint(pool_mint_info)?;
        stake_pool.check_reserve_stake(reserve_stake_account_info)?;

        if stake_pool.token_program_id != *token_program_info.key {
            return Err(ProgramError::IncorrectProgramId);
        }
        check_system_program(system_program_info.key)?;

        if stake_pool.manager_fee_account != *manager_fee_info.key {
            return Err(StakePoolError::InvalidFeeAccount.into());
        }
        // There is no bypass if the manager fee account is invalid. Deposits
        // don't hold user funds hostage, so if the fee account is invalid, users
        // cannot deposit in the pool.  Let it fail here!

        // We want this to hold to ensure that deposit_sol mints pool tokens
        // at the right price
        if stake_pool.last_update_epoch < clock.epoch {
            return Err(StakePoolError::StakeListAndPoolOutOfDate.into());
        }

        let new_pool_tokens = stake_pool
            .calc_pool_tokens_for_deposit(deposit_lamports)
            .ok_or(StakePoolError::CalculationFailure)?;

        let pool_tokens_sol_deposit_fee = stake_pool
            .calc_pool_tokens_sol_deposit_fee(new_pool_tokens)
            .ok_or(StakePoolError::CalculationFailure)?;
        let pool_tokens_user = new_pool_tokens
            .checked_sub(pool_tokens_sol_deposit_fee)
            .ok_or(StakePoolError::CalculationFailure)?;

        let pool_tokens_referral_fee = stake_pool
            .calc_pool_tokens_sol_referral_fee(pool_tokens_sol_deposit_fee)
            .ok_or(StakePoolError::CalculationFailure)?;
        let pool_tokens_manager_deposit_fee = pool_tokens_sol_deposit_fee
            .checked_sub(pool_tokens_referral_fee)
            .ok_or(StakePoolError::CalculationFailure)?;

        if pool_tokens_user
            .saturating_add(pool_tokens_manager_deposit_fee)
            .saturating_add(pool_tokens_referral_fee)
            != new_pool_tokens
        {
            return Err(StakePoolError::CalculationFailure.into());
        }

        if pool_tokens_user == 0 {
            return Err(StakePoolError::DepositTooSmall.into());
        }

        if let Some(minimum_pool_tokens_out) = minimum_pool_tokens_out {
            if pool_tokens_user < minimum_pool_tokens_out {
                return Err(StakePoolError::ExceededSlippage.into());
            }
        }

        if !is_wsol_path {
            Self::sol_transfer(
                from_user_lamports_info.clone(),
                reserve_stake_account_info.clone(),
                deposit_lamports,
            )?;
        }

        Self::token_mint_to(
            stake_pool_info.key,
            token_program_info.clone(),
            pool_mint_info.clone(),
            dest_user_pool_info.clone(),
            withdraw_authority_info.clone(),
            AUTHORITY_WITHDRAW,
            stake_pool.stake_withdraw_bump_seed,
            pool_tokens_user,
        )?;

        if pool_tokens_manager_deposit_fee > 0 {
            Self::token_mint_to(
                stake_pool_info.key,
                token_program_info.clone(),
                pool_mint_info.clone(),
                manager_fee_info.clone(),
                withdraw_authority_info.clone(),
                AUTHORITY_WITHDRAW,
                stake_pool.stake_withdraw_bump_seed,
                pool_tokens_manager_deposit_fee,
            )?;
        }

        if pool_tokens_referral_fee > 0 {
            Self::token_mint_to(
                stake_pool_info.key,
                token_program_info.clone(),
                pool_mint_info.clone(),
                referrer_fee_info.clone(),
                withdraw_authority_info.clone(),
                AUTHORITY_WITHDRAW,
                stake_pool.stake_withdraw_bump_seed,
                pool_tokens_referral_fee,
            )?;
        }

        stake_pool.pool_token_supply = stake_pool
            .pool_token_supply
            .checked_add(new_pool_tokens)
            .ok_or(StakePoolError::CalculationFailure)?;
        stake_pool.total_lamports = stake_pool
            .total_lamports
            .checked_add(deposit_lamports)
            .ok_or(StakePoolError::CalculationFailure)?;
        borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)?;

        Ok(())
    }

    /// Processes [`WithdrawStake`](enum.Instruction.html).
    #[inline(never)] // needed to avoid stack size violation
    fn process_withdraw_stake(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        pool_tokens: u64,
        minimum_lamports_out: Option<u64>,
        user_stake_seed: Option<u64>,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let validator_list_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let stake_split_from = next_account_info(account_info_iter)?;
        let stake_split_to = next_account_info(account_info_iter)?;
        let user_stake_authority_info = next_account_info(account_info_iter)?;
        let user_transfer_authority_info = next_account_info(account_info_iter)?;
        let burn_from_pool_info = next_account_info(account_info_iter)?;
        let manager_fee_info = next_account_info(account_info_iter)?;
        let pool_mint_info = next_account_info(account_info_iter)?;
        let clock_info = next_account_info(account_info_iter)?;
        let clock = &Clock::from_account_info(clock_info)?;
        let token_program_info = next_account_info(account_info_iter)?;
        let stake_program_info = next_account_info(account_info_iter)?;

        check_stake_program(stake_program_info.key)?;
        check_account_owner(stake_pool_info, program_id)?;
        let mut stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        let decimals = stake_pool.check_mint(pool_mint_info)?;
        stake_pool.check_validator_list(validator_list_info)?;
        stake_pool.check_authority_withdraw(
            withdraw_authority_info.key,
            program_id,
            stake_pool_info.key,
        )?;

        if stake_pool.manager_fee_account != *manager_fee_info.key {
            return Err(StakePoolError::InvalidFeeAccount.into());
        }
        if stake_pool.token_program_id != *token_program_info.key {
            return Err(ProgramError::IncorrectProgramId);
        }

        if stake_pool.last_update_epoch < clock.epoch {
            return Err(StakePoolError::StakeListAndPoolOutOfDate.into());
        }

        check_account_owner(validator_list_info, program_id)?;
        let mut validator_list_data = validator_list_info.data.borrow_mut();
        let (header, mut validator_list) =
            ValidatorListHeader::deserialize_vec(&mut validator_list_data)?;
        if !header.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        // To prevent a faulty manager fee account from preventing withdrawals
        // if the token program does not own the account, or if the account is not
        // initialized
        let pool_tokens_fee = if stake_pool.manager_fee_account == *burn_from_pool_info.key
            || stake_pool.check_manager_fee_info(manager_fee_info).is_err()
        {
            0
        } else {
            stake_pool
                .calc_pool_tokens_stake_withdrawal_fee(pool_tokens)
                .ok_or(StakePoolError::CalculationFailure)?
        };
        let pool_tokens_burnt = pool_tokens
            .checked_sub(pool_tokens_fee)
            .ok_or(StakePoolError::CalculationFailure)?;

        let mut withdraw_lamports = stake_pool
            .calc_lamports_withdraw_amount(pool_tokens_burnt)
            .ok_or(StakePoolError::CalculationFailure)?;

        if withdraw_lamports == 0 {
            return Err(StakePoolError::WithdrawalTooSmall.into());
        }

        if let Some(minimum_lamports_out) = minimum_lamports_out {
            if withdraw_lamports < minimum_lamports_out {
                return Err(StakePoolError::ExceededSlippage.into());
            }
        }

        let stake_minimum_delegation = stake::tools::get_minimum_delegation()?;
        let stake_state = try_from_slice_unchecked::<stake::state::StakeStateV2>(
            &stake_split_from.data.borrow(),
        )?;
        let meta = stake_state.meta().ok_or(StakePoolError::WrongStakeStake)?;
        let required_lamports = minimum_stake_lamports(&meta, stake_minimum_delegation);

        let lamports_per_pool_token = stake_pool
            .get_lamports_per_pool_token()
            .ok_or(StakePoolError::CalculationFailure)?;
        let minimum_lamports_with_tolerance =
            required_lamports.saturating_add(lamports_per_pool_token);

        let has_active_stake = validator_list
            .find::<ValidatorStakeInfo, _>(|x| {
                ValidatorStakeInfo::active_lamports_greater_than(
                    x,
                    &minimum_lamports_with_tolerance,
                ) && ValidatorStakeInfo::is_active(x)
            })
            .is_some();
        let has_transient_stake = validator_list
            .find::<ValidatorStakeInfo, _>(|x| {
                ValidatorStakeInfo::transient_lamports_greater_than(
                    x,
                    &minimum_lamports_with_tolerance,
                ) && ValidatorStakeInfo::is_active(x)
            })
            .is_some();

        let validator_list_item_info = if *stake_split_from.key == stake_pool.reserve_stake {
            // check that the validator stake accounts have no withdrawable stake
            if has_transient_stake || has_active_stake {
                msg!("Error withdrawing from reserve: validator stake accounts have lamports available, please use those first.");
                return Err(StakePoolError::StakeLamportsNotEqualToMinimum.into());
            }

            // check that reserve has enough
            let minimum_reserve_lamports = minimum_reserve_lamports(&meta);
            if stake_split_from
                .lamports()
                .saturating_sub(withdraw_lamports)
                < minimum_reserve_lamports
            {
                msg!("Attempting to withdraw {} lamports, maximum possible SOL withdrawal is {} lamports",
                    withdraw_lamports,
                    stake_split_from.lamports().saturating_sub(minimum_reserve_lamports)
                );
                return Err(StakePoolError::SolWithdrawalTooLarge.into());
            }
            None
        } else {
            let delegation = stake_state
                .delegation()
                .ok_or(StakePoolError::WrongStakeStake)?;
            let vote_account_address = delegation.voter_pubkey;

            if let Some(preferred_withdraw_validator) =
                stake_pool.preferred_withdraw_validator_vote_address
            {
                // Defensive check, in case the preferred validator was somehow
                // removed.
                if let Some(preferred_validator_info) = validator_list
                    .find::<ValidatorStakeInfo, _>(|x| {
                        ValidatorStakeInfo::memcmp_pubkey(x, &preferred_withdraw_validator)
                    })
                {
                    let available_lamports =
                        u64::from(preferred_validator_info.active_stake_lamports)
                            .saturating_sub(minimum_lamports_with_tolerance);
                    if preferred_withdraw_validator != vote_account_address
                        && available_lamports > 0
                    {
                        msg!("Validator vote address {} is preferred for withdrawals, it currently has {} lamports available. Please withdraw those before using other validator stake accounts.", preferred_withdraw_validator, u64::from(preferred_validator_info.active_stake_lamports));
                        return Err(StakePoolError::IncorrectWithdrawVoteAddress.into());
                    }
                } else {
                    msg!("Preferred withdraw validator not found, allowing withdrawal from any validator");
                }
            }

            let validator_stake_info = validator_list
                .find_mut::<ValidatorStakeInfo, _>(|x| {
                    ValidatorStakeInfo::memcmp_pubkey(x, &vote_account_address)
                })
                .ok_or(StakePoolError::ValidatorNotFound)?;

            let withdraw_source = if has_active_stake {
                // if there's any active stake, we must withdraw from an active
                // stake account
                check_validator_stake_address(
                    program_id,
                    stake_pool_info.key,
                    stake_split_from.key,
                    &vote_account_address,
                    NonZeroU32::new(validator_stake_info.validator_seed_suffix.into()),
                )?;
                StakeWithdrawSource::Active
            } else if has_transient_stake
                || validator_stake_info.transient_stake_lamports != 0.into()
            {
                // if there's any transient stake, we must withdraw from there
                // Be particularly cautious to avoid removing a validator with
                // transient lamports tied to it
                check_transient_stake_address(
                    program_id,
                    stake_pool_info.key,
                    stake_split_from.key,
                    &vote_account_address,
                    validator_stake_info.transient_seed_suffix.into(),
                )?;
                StakeWithdrawSource::Transient
            } else {
                // if there's no active or transient stake, we can take the whole account
                check_validator_stake_address(
                    program_id,
                    stake_pool_info.key,
                    stake_split_from.key,
                    &vote_account_address,
                    NonZeroU32::new(validator_stake_info.validator_seed_suffix.into()),
                )?;
                StakeWithdrawSource::ValidatorRemoval
            };

            if validator_stake_info.status != StakeStatus::Active.into() {
                msg!("Validator is marked for removal and no longer allowing withdrawals");
                return Err(StakePoolError::ValidatorNotFound.into());
            }

            match withdraw_source {
                StakeWithdrawSource::Active | StakeWithdrawSource::Transient => {
                    let remaining_lamports = stake_split_from
                        .lamports()
                        .saturating_sub(withdraw_lamports);
                    if remaining_lamports < required_lamports {
                        msg!("Attempting to withdraw {} lamports from validator account with {} stake lamports, {} must remain", withdraw_lamports, stake_split_from.lamports(), required_lamports);
                        return Err(StakePoolError::StakeLamportsNotEqualToMinimum.into());
                    }
                }
                StakeWithdrawSource::ValidatorRemoval => {
                    let split_from_lamports = stake_split_from.lamports();
                    let upper_bound = split_from_lamports.saturating_add(lamports_per_pool_token);
                    if withdraw_lamports < split_from_lamports || withdraw_lamports > upper_bound {
                        msg!(
                            "Cannot withdraw a whole account worth {} lamports, \
                              must withdraw at least {} lamports worth of pool tokens \
                              with a margin of {} lamports",
                            withdraw_lamports,
                            split_from_lamports,
                            lamports_per_pool_token
                        );
                        return Err(StakePoolError::StakeLamportsNotEqualToMinimum.into());
                    }
                    // truncate the lamports down to the amount in the account
                    withdraw_lamports = split_from_lamports;

                    // reset the preferred validator if needed
                    if stake_pool.preferred_deposit_validator_vote_address
                        == Some(vote_account_address)
                    {
                        stake_pool.preferred_deposit_validator_vote_address = None;
                    }
                    if stake_pool.preferred_withdraw_validator_vote_address
                        == Some(vote_account_address)
                    {
                        stake_pool.preferred_withdraw_validator_vote_address = None;
                    }
                }
            }
            Some((validator_stake_info, withdraw_source))
        };

        // WithdrawStakeWithSession path - create user stake account PDA
        // Tuple: (user_pubkey, program_signer_bump, program_signer_info, signer_or_session_info, split_lamports)
        let session_pda_info: Option<(Pubkey, u8, AccountInfo, AccountInfo, u64)> =
            if let Some(seed) = user_stake_seed {
                use crate::USER_STAKE_SEED_PREFIX;
                use fogo_sessions_sdk::session::Session;
                use fogo_sessions_sdk::token::PROGRAM_SIGNER_SEED;

                let is_validator_removal = matches!(
                    &validator_list_item_info,
                    Some((_, StakeWithdrawSource::ValidatorRemoval))
                );

                let program_signer_info = next_account_info(account_info_iter)?;
                let system_program_info = next_account_info(account_info_iter)?;
                let reserve_stake_info = next_account_info(account_info_iter)?;
                let stake_history_info = next_account_info(account_info_iter)?;

                check_system_program(system_program_info.key)?;

                if stake_pool.reserve_stake != *reserve_stake_info.key {
                    msg!("Invalid reserve stake account");
                    return Err(StakePoolError::InvalidProgramAddress.into());
                }

                let (expected_program_signer, program_signer_bump) =
                    Pubkey::find_program_address(&[PROGRAM_SIGNER_SEED], program_id);
                if expected_program_signer != *program_signer_info.key {
                    msg!("Invalid program signer account");
                    return Err(ProgramError::InvalidSeeds);
                }

                let signer_or_session_info = user_stake_authority_info;
                let user_pubkey = Session::extract_user_from_signer_or_session(
                    signer_or_session_info,
                    program_id,
                )?;

                // Validate stake account PDA
                let (expected_stake_pda, stake_pda_bump) = Pubkey::find_program_address(
                    &[
                        USER_STAKE_SEED_PREFIX,
                        user_pubkey.as_ref(),
                        &seed.to_le_bytes(),
                    ],
                    program_id,
                );
                if expected_stake_pda != *stake_split_to.key {
                    msg!("Invalid stake account PDA");
                    return Err(ProgramError::InvalidSeeds);
                }

                // Calculate rent for stake account
                let stake_space = stake::state::StakeStateV2::size_of();
                let stake_rent = Rent::get()?.minimum_balance(stake_space);

                let stake_pda_seeds: &[&[u8]] = &[
                    USER_STAKE_SEED_PREFIX,
                    user_pubkey.as_ref(),
                    &seed.to_le_bytes(),
                    &[stake_pda_bump],
                ];

                // Create stake account if needed
                // - System-owned: new account or GC'd zombie, create it
                // - Stake-owned + Uninitialized: zombie not yet GC'd, safe to reuse
                // - Stake-owned + Initialized: active stake, reject
                if stake_split_to.owner == &system_program::id() {
                    create_stake_account(stake_split_to.clone(), stake_pda_seeds, stake_space)?;
                } else if stake_split_to.owner == &stake::program::id() {
                    let stake_state = try_from_slice_unchecked::<stake::state::StakeStateV2>(
                        &stake_split_to.data.borrow(),
                    )?;
                    if !matches!(stake_state, stake::state::StakeStateV2::Uninitialized) {
                        msg!("Stake account PDA already in use. Use a different seed.");
                        return Err(StakePoolError::AlreadyInUse.into());
                    }
                    // Zombie account - already allocated and assigned, skip create
                } else {
                    msg!("Stake account PDA has invalid owner");
                    return Err(ProgramError::IllegalOwner);
                }

                let split_lamports = if is_validator_removal {
                    // Full balance includes rent, no additional funding needed
                    withdraw_lamports
                } else {
                    if stake_rent >= reserve_stake_info.lamports() {
                        return Err(StakePoolError::ReserveDepleted.into());
                    }
                    Self::stake_withdraw(
                        stake_pool_info.key,
                        reserve_stake_info.clone(),
                        withdraw_authority_info.clone(),
                        AUTHORITY_WITHDRAW,
                        stake_pool.stake_withdraw_bump_seed,
                        stake_split_to.clone(),
                        clock_info.clone(),
                        stake_history_info.clone(),
                        stake_rent,
                    )?;
                    withdraw_lamports.saturating_sub(stake_rent)
                };

                Some((
                    user_pubkey,
                    program_signer_bump,
                    program_signer_info.clone(),
                    signer_or_session_info.clone(),
                    split_lamports,
                ))
            } else {
                None
            };

        let actual_split_amount = if let Some((_, _, _, _, split_lamports)) = &session_pda_info {
            *split_lamports
        } else {
            withdraw_lamports
        };

        Self::stake_split(
            stake_pool_info.key,
            stake_split_from.clone(),
            withdraw_authority_info.clone(),
            AUTHORITY_WITHDRAW,
            stake_pool.stake_withdraw_bump_seed,
            actual_split_amount,
            stake_split_to.clone(),
        )?;

        // WithdrawStakeWithSession path - use session for token ops, set PDA as its own authority
        if let Some((
            user_pubkey,
            program_signer_bump,
            program_signer_info,
            signer_or_session_info,
            _split_lamports,
        )) = session_pda_info
        {
            use fogo_sessions_sdk::token::instruction::{burn, transfer_checked};
            use fogo_sessions_sdk::token::PROGRAM_SIGNER_SEED;
            use solana_program::program_pack::Pack;

            // Validate burn_from_pool is owned by the session user
            let burn_from_pool_data =
                spl_token::state::Account::unpack(&burn_from_pool_info.data.borrow())?;
            if burn_from_pool_data.owner != user_pubkey {
                msg!("`burn_from_pool` is not owned by the session user");
                return Err(ProgramError::InvalidAccountData);
            }

            let program_signer_seeds: &[&[u8]] = &[PROGRAM_SIGNER_SEED, &[program_signer_bump]];

            // Burn using session
            invoke_signed(
                &burn(
                    token_program_info.key,
                    burn_from_pool_info.key,
                    pool_mint_info.key,
                    signer_or_session_info.key,
                    Some(program_signer_info.key),
                    pool_tokens_burnt,
                )?,
                &[
                    burn_from_pool_info.clone(),
                    pool_mint_info.clone(),
                    signer_or_session_info.clone(),
                    program_signer_info.clone(),
                ],
                &[program_signer_seeds],
            )?;

            // Transfer fee using session
            if pool_tokens_fee > 0 {
                invoke_signed(
                    &transfer_checked(
                        token_program_info.key,
                        burn_from_pool_info.key,
                        pool_mint_info.key,
                        manager_fee_info.key,
                        signer_or_session_info.key,
                        Some(program_signer_info.key),
                        pool_tokens_fee,
                        decimals,
                    )?,
                    &[
                        burn_from_pool_info.clone(),
                        pool_mint_info.clone(),
                        manager_fee_info.clone(),
                        signer_or_session_info.clone(),
                        program_signer_info.clone(),
                    ],
                    &[program_signer_seeds],
                )?;
            }

            // Only deactivate if the stake is active and not yet deactivated.
            // stake_deactivate fails with AlreadyDeactivated if called on reserve/transient stake.
            let split_to_state = try_from_slice_unchecked::<stake::state::StakeStateV2>(
                &stake_split_to.data.borrow(),
            )?;
            if let stake::state::StakeStateV2::Stake(_meta, stake, _) = split_to_state {
                if stake.delegation.deactivation_epoch == Epoch::MAX {
                    // Stake is active and not yet deactivated - deactivate it now
                    Self::stake_deactivate(
                        stake_split_to.clone(),
                        clock_info.clone(),
                        withdraw_authority_info.clone(),
                        stake_pool_info.key,
                        AUTHORITY_WITHDRAW,
                        stake_pool.stake_withdraw_bump_seed,
                    )?;
                }
            }

            // Set stake authority to the PDA itself so it can sign the later withdrawal
            Self::stake_authorize_signed(
                stake_pool_info.key,
                stake_split_to.clone(),
                withdraw_authority_info.clone(),
                AUTHORITY_WITHDRAW,
                stake_pool.stake_withdraw_bump_seed,
                stake_split_to.key, // The PDA becomes its own authority
                clock_info.clone(),
            )?;

            // Update stake pool: withdraw_lamports left the pool (split from validator + rent from reserve)
            stake_pool.pool_token_supply = stake_pool
                .pool_token_supply
                .checked_sub(pool_tokens_burnt)
                .ok_or(StakePoolError::CalculationFailure)?;
            stake_pool.total_lamports = stake_pool
                .total_lamports
                .checked_sub(withdraw_lamports)
                .ok_or(StakePoolError::CalculationFailure)?;
            borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)?;

            // Update validator list (only split_lamports came from the validator stake)
            if let Some((validator_list_item, withdraw_source)) = validator_list_item_info {
                match withdraw_source {
                    StakeWithdrawSource::Active => {
                        validator_list_item.active_stake_lamports =
                            u64::from(validator_list_item.active_stake_lamports)
                                .checked_sub(actual_split_amount)
                                .ok_or(StakePoolError::CalculationFailure)?
                                .into()
                    }
                    StakeWithdrawSource::Transient => {
                        validator_list_item.transient_stake_lamports =
                            u64::from(validator_list_item.transient_stake_lamports)
                                .checked_sub(actual_split_amount)
                                .ok_or(StakePoolError::CalculationFailure)?
                                .into()
                    }
                    StakeWithdrawSource::ValidatorRemoval => {
                        validator_list_item.active_stake_lamports =
                            u64::from(validator_list_item.active_stake_lamports)
                                .checked_sub(actual_split_amount)
                                .ok_or(StakePoolError::CalculationFailure)?
                                .into();
                        if u64::from(validator_list_item.active_stake_lamports) != 0 {
                            msg!("Attempting to remove a validator from the pool, but withdrawal leaves {} lamports, update the pool to merge any unaccounted lamports",
                                u64::from(validator_list_item.active_stake_lamports));
                            return Err(StakePoolError::StakeListAndPoolOutOfDate.into());
                        }
                        validator_list_item.status = StakeStatus::ReadyForRemoval.into();
                    }
                }
            }

            return Ok(());
        }

        // Regular path - use standard token operations

        Self::token_burn(
            token_program_info.clone(),
            burn_from_pool_info.clone(),
            pool_mint_info.clone(),
            user_transfer_authority_info.clone(),
            pool_tokens_burnt,
        )?;

        Self::stake_authorize_signed(
            stake_pool_info.key,
            stake_split_to.clone(),
            withdraw_authority_info.clone(),
            AUTHORITY_WITHDRAW,
            stake_pool.stake_withdraw_bump_seed,
            user_stake_authority_info.key,
            clock_info.clone(),
        )?;

        if pool_tokens_fee > 0 {
            Self::token_transfer(
                token_program_info.clone(),
                burn_from_pool_info.clone(),
                pool_mint_info.clone(),
                manager_fee_info.clone(),
                user_transfer_authority_info.clone(),
                pool_tokens_fee,
                decimals,
            )?;
        }

        stake_pool.pool_token_supply = stake_pool
            .pool_token_supply
            .checked_sub(pool_tokens_burnt)
            .ok_or(StakePoolError::CalculationFailure)?;
        stake_pool.total_lamports = stake_pool
            .total_lamports
            .checked_sub(withdraw_lamports)
            .ok_or(StakePoolError::CalculationFailure)?;
        borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)?;

        if let Some((validator_list_item, withdraw_source)) = validator_list_item_info {
            match withdraw_source {
                StakeWithdrawSource::Active => {
                    validator_list_item.active_stake_lamports =
                        u64::from(validator_list_item.active_stake_lamports)
                            .checked_sub(withdraw_lamports)
                            .ok_or(StakePoolError::CalculationFailure)?
                            .into()
                }
                StakeWithdrawSource::Transient => {
                    validator_list_item.transient_stake_lamports =
                        u64::from(validator_list_item.transient_stake_lamports)
                            .checked_sub(withdraw_lamports)
                            .ok_or(StakePoolError::CalculationFailure)?
                            .into()
                }
                StakeWithdrawSource::ValidatorRemoval => {
                    validator_list_item.active_stake_lamports =
                        u64::from(validator_list_item.active_stake_lamports)
                            .checked_sub(withdraw_lamports)
                            .ok_or(StakePoolError::CalculationFailure)?
                            .into();
                    if u64::from(validator_list_item.active_stake_lamports) != 0 {
                        msg!("Attempting to remove a validator from the pool, but withdrawal leaves {} lamports, update the pool to merge any unaccounted lamports",
                            u64::from(validator_list_item.active_stake_lamports));
                        return Err(StakePoolError::StakeListAndPoolOutOfDate.into());
                    }
                    // since we already checked that there's no transient stake,
                    // we can immediately set this as ready for removal
                    validator_list_item.status = StakeStatus::ReadyForRemoval.into();
                }
            }
        }

        Ok(())
    }

    /// Processes [`WithdrawWsolWithSession`](enum.Instruction.html).
    #[inline(never)] // needed to avoid stack size violation
    fn process_withdraw_wsol_with_session(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        pool_tokens: u64,
        minimum_lamports_out: Option<u64>,
    ) -> ProgramResult {
        use fogo_sessions_sdk::session::Session;
        use fogo_sessions_sdk::token::PROGRAM_SIGNER_SEED;
        use solana_program::program_pack::Pack;

        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let signer_or_session_info = next_account_info(account_info_iter)?;
        let burn_from_pool_info = next_account_info(account_info_iter)?;
        let reserve_stake_info = next_account_info(account_info_iter)?;
        let destination_account_info = next_account_info(account_info_iter)?;
        let manager_fee_info = next_account_info(account_info_iter)?;
        let pool_mint_info = next_account_info(account_info_iter)?;
        let clock_info = next_account_info(account_info_iter)?;
        let stake_history_info = next_account_info(account_info_iter)?;
        let stake_program_info = next_account_info(account_info_iter)?;
        let token_program_info = next_account_info(account_info_iter)?;

        // wsol-specific accounts
        let wsol_mint_info = next_account_info(account_info_iter)?;
        let program_signer_info = next_account_info(account_info_iter)?;
        let user_wallet_info = next_account_info(account_info_iter)?;
        let system_program_info = next_account_info(account_info_iter)?;

        let sol_withdraw_authority_info = next_account_info(account_info_iter);

        if *wsol_mint_info.key != spl_token::native_mint::id() {
            msg!("`wsol_mint` is not the native WSOL mint");
            return Err(ProgramError::InvalidAccountData);
        }

        if *wsol_mint_info.owner != *token_program_info.key {
            msg!("`wsol_mint` is not owned by the token program");
            return Err(ProgramError::InvalidAccountData);
        }

        let user_pubkey =
            Session::extract_user_from_signer_or_session(signer_or_session_info, program_id)?;

        // Verify burn_from_pool_info is owned by the user
        let burn_from_pool_data =
            spl_token::state::Account::unpack(&burn_from_pool_info.data.borrow())?;
        if burn_from_pool_data.owner != user_pubkey {
            msg!("`burn_from_pool` is not owned by the session user");
            return Err(ProgramError::InvalidAccountData);
        }

        let (expected_program_signer, program_signer_bump) =
            Pubkey::find_program_address(&[PROGRAM_SIGNER_SEED], program_id);

        if *program_signer_info.key != expected_program_signer {
            msg!("`program_signer` does not match expected address");
            return Err(ProgramError::InvalidSeeds);
        }

        let program_signer_seeds: &[&[u8]] = &[PROGRAM_SIGNER_SEED, &[program_signer_bump]];

        let rent = Rent::get()?;

        // Verify destination_account_info is the correct wSOL ATA for user_wallet
        let expected_ata =
            spl_associated_token_account::get_associated_token_address_with_program_id(
                user_wallet_info.key,
                wsol_mint_info.key,
                token_program_info.key,
            );
        if *destination_account_info.key != expected_ata {
            msg!("destination_account is not the wSOL ATA for user_wallet");
            return Err(ProgramError::InvalidAccountData);
        }

        let ata_creation_cost = rent
            .minimum_balance(spl_token::state::Account::LEN)
            .saturating_sub(destination_account_info.lamports());

        let withdraw_lamports = {
            let mut accounts: Vec<AccountInfo> = vec![
                stake_pool_info.clone(),
                withdraw_authority_info.clone(),
                signer_or_session_info.clone(),
                burn_from_pool_info.clone(),
                reserve_stake_info.clone(),
                program_signer_info.clone(),
                manager_fee_info.clone(),
                pool_mint_info.clone(),
                clock_info.clone(),
                stake_history_info.clone(),
                stake_program_info.clone(),
                token_program_info.clone(),
            ];

            if let Ok(sol_withdraw_authority_info) = sol_withdraw_authority_info {
                accounts.push(sol_withdraw_authority_info.clone());
            } else {
                // dummy to keep account order consistent
                accounts.push(stake_program_info.clone());
            }

            accounts.push(program_signer_info.clone());

            let balance_before = program_signer_info.lamports();
            Self::process_withdraw_sol(program_id, &accounts, pool_tokens, minimum_lamports_out)?;
            program_signer_info
                .lamports()
                .saturating_sub(balance_before)
        };

        if ata_creation_cost > 0 {
            if withdraw_lamports < ata_creation_cost {
                msg!("Withdrawal too small to cover ATA rent");
                return Err(StakePoolError::WithdrawalTooSmall.into());
            }

            invoke_signed(
                &spl_associated_token_account::instruction::create_associated_token_account_idempotent(
                    program_signer_info.key,
                    user_wallet_info.key,
                    wsol_mint_info.key,
                    token_program_info.key,
                ),
                &[
                    program_signer_info.clone(),
                    destination_account_info.clone(),
                    user_wallet_info.clone(),
                    wsol_mint_info.clone(),
                    system_program_info.clone(),
                    token_program_info.clone(),
                ],
                &[program_signer_seeds],
            )?;
        }

        let user_lamports = withdraw_lamports.saturating_sub(ata_creation_cost);
        if user_lamports > 0 {
            invoke_signed(
                &system_instruction::transfer(
                    program_signer_info.key,
                    destination_account_info.key,
                    user_lamports,
                ),
                &[
                    program_signer_info.clone(),
                    destination_account_info.clone(),
                    system_program_info.clone(),
                ],
                &[program_signer_seeds],
            )?;
        }

        invoke(
            &spl_token::instruction::sync_native(
                token_program_info.key,
                destination_account_info.key,
            )?,
            core::slice::from_ref(destination_account_info),
        )?;

        Ok(())
    }

    /// Processes [`WithdrawSol`](enum.Instruction.html).
    #[inline(never)] // needed to avoid stack size violation
    fn process_withdraw_sol(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        pool_tokens: u64,
        minimum_lamports_out: Option<u64>,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let user_transfer_authority_info = next_account_info(account_info_iter)?;
        let burn_from_pool_info = next_account_info(account_info_iter)?;
        let reserve_stake_info = next_account_info(account_info_iter)?;
        let destination_lamports_info = next_account_info(account_info_iter)?;
        let manager_fee_info = next_account_info(account_info_iter)?;
        let pool_mint_info = next_account_info(account_info_iter)?;
        let clock_info = next_account_info(account_info_iter)?;
        let stake_history_info = next_account_info(account_info_iter)?;
        let stake_program_info = next_account_info(account_info_iter)?;
        let token_program_info = next_account_info(account_info_iter)?;
        let sol_withdraw_authority_info = next_account_info(account_info_iter);

        check_account_owner(stake_pool_info, program_id)?;
        let mut stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        stake_pool.check_authority_withdraw(
            withdraw_authority_info.key,
            program_id,
            stake_pool_info.key,
        )?;
        stake_pool.check_sol_withdraw_authority(sol_withdraw_authority_info)?;
        let decimals = stake_pool.check_mint(pool_mint_info)?;
        stake_pool.check_reserve_stake(reserve_stake_info)?;

        if stake_pool.token_program_id != *token_program_info.key {
            return Err(ProgramError::IncorrectProgramId);
        }
        check_stake_program(stake_program_info.key)?;

        if stake_pool.manager_fee_account != *manager_fee_info.key {
            return Err(StakePoolError::InvalidFeeAccount.into());
        }

        // We want this to hold to ensure that withdraw_sol burns pool tokens
        // at the right price
        if stake_pool.last_update_epoch < Clock::get()?.epoch {
            return Err(StakePoolError::StakeListAndPoolOutOfDate.into());
        }

        // To prevent a faulty manager fee account from preventing withdrawals
        // if the token program does not own the account, or if the account is not
        // initialized
        let pool_tokens_fee = if stake_pool.manager_fee_account == *burn_from_pool_info.key
            || stake_pool.check_manager_fee_info(manager_fee_info).is_err()
        {
            0
        } else {
            stake_pool
                .calc_pool_tokens_sol_withdrawal_fee(pool_tokens)
                .ok_or(StakePoolError::CalculationFailure)?
        };
        let pool_tokens_burnt = pool_tokens
            .checked_sub(pool_tokens_fee)
            .ok_or(StakePoolError::CalculationFailure)?;

        let withdraw_lamports = stake_pool
            .calc_lamports_withdraw_amount(pool_tokens_burnt)
            .ok_or(StakePoolError::CalculationFailure)?;

        if withdraw_lamports == 0 {
            return Err(StakePoolError::WithdrawalTooSmall.into());
        }

        if let Some(minimum_lamports_out) = minimum_lamports_out {
            if withdraw_lamports < minimum_lamports_out {
                return Err(StakePoolError::ExceededSlippage.into());
            }
        }

        let new_reserve_lamports = reserve_stake_info
            .lamports()
            .saturating_sub(withdraw_lamports);
        let stake_state = try_from_slice_unchecked::<stake::state::StakeStateV2>(
            &reserve_stake_info.data.borrow(),
        )?;
        if let stake::state::StakeStateV2::Initialized(meta) = stake_state {
            let minimum_reserve_lamports = minimum_reserve_lamports(&meta);
            if new_reserve_lamports < minimum_reserve_lamports {
                msg!("Attempting to withdraw {} lamports, maximum possible SOL withdrawal is {} lamports",
                    withdraw_lamports,
                    reserve_stake_info.lamports().saturating_sub(minimum_reserve_lamports)
                );
                return Err(StakePoolError::SolWithdrawalTooLarge.into());
            }
        } else {
            msg!("Reserve stake account not in initialized state");
            return Err(StakePoolError::WrongStakeStake.into());
        };

        // Determine if we are using the WSOL special path (with program signer account)
        if let Ok(program_signer_info) = next_account_info(account_info_iter) {
            use fogo_sessions_sdk::token::instruction::burn;
            use fogo_sessions_sdk::token::instruction::transfer_checked;
            use fogo_sessions_sdk::token::PROGRAM_SIGNER_SEED;

            let (expected_program_signer, program_signer_bump) =
                Pubkey::find_program_address(&[PROGRAM_SIGNER_SEED], program_id);

            if expected_program_signer != *program_signer_info.key {
                msg!("Invalid program signer account");
                return Err(ProgramError::InvalidSeeds);
            }

            let program_signer_seeds: &[&[u8]] = &[PROGRAM_SIGNER_SEED, &[program_signer_bump]];

            invoke_signed(
                &burn(
                    token_program_info.key,
                    burn_from_pool_info.key,
                    pool_mint_info.key,
                    user_transfer_authority_info.key,
                    Some(program_signer_info.key),
                    pool_tokens_burnt,
                )?,
                &[
                    burn_from_pool_info.clone(),
                    pool_mint_info.clone(),
                    user_transfer_authority_info.clone(),
                    program_signer_info.clone(),
                ],
                &[program_signer_seeds],
            )?;

            if pool_tokens_fee > 0 {
                invoke_signed(
                    &transfer_checked(
                        token_program_info.key,
                        burn_from_pool_info.key,
                        pool_mint_info.key,
                        manager_fee_info.key,
                        user_transfer_authority_info.key,
                        Some(program_signer_info.key),
                        pool_tokens_fee,
                        decimals,
                    )?,
                    &[
                        burn_from_pool_info.clone(),
                        pool_mint_info.clone(),
                        manager_fee_info.clone(),
                        user_transfer_authority_info.clone(),
                        program_signer_info.clone(),
                    ],
                    &[program_signer_seeds],
                )?;
            }
        } else {
            Self::token_burn(
                token_program_info.clone(),
                burn_from_pool_info.clone(),
                pool_mint_info.clone(),
                user_transfer_authority_info.clone(),
                pool_tokens_burnt,
            )?;

            if pool_tokens_fee > 0 {
                Self::token_transfer(
                    token_program_info.clone(),
                    burn_from_pool_info.clone(),
                    pool_mint_info.clone(),
                    manager_fee_info.clone(),
                    user_transfer_authority_info.clone(),
                    pool_tokens_fee,
                    decimals,
                )?;
            }
        }

        Self::stake_withdraw(
            stake_pool_info.key,
            reserve_stake_info.clone(),
            withdraw_authority_info.clone(),
            AUTHORITY_WITHDRAW,
            stake_pool.stake_withdraw_bump_seed,
            destination_lamports_info.clone(),
            clock_info.clone(),
            stake_history_info.clone(),
            withdraw_lamports,
        )?;

        stake_pool.pool_token_supply = stake_pool
            .pool_token_supply
            .checked_sub(pool_tokens_burnt)
            .ok_or(StakePoolError::CalculationFailure)?;
        stake_pool.total_lamports = stake_pool
            .total_lamports
            .checked_sub(withdraw_lamports)
            .ok_or(StakePoolError::CalculationFailure)?;
        borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)?;

        Ok(())
    }

    #[inline(never)]
    fn process_create_pool_token_metadata(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        name: String,
        symbol: String,
        uri: String,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let manager_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let pool_mint_info = next_account_info(account_info_iter)?;
        let payer_info = next_account_info(account_info_iter)?;
        let metadata_info = next_account_info(account_info_iter)?;
        let mpl_token_metadata_program_info = next_account_info(account_info_iter)?;
        let system_program_info = next_account_info(account_info_iter)?;

        if !payer_info.is_signer {
            msg!("Payer did not sign metadata creation");
            return Err(StakePoolError::SignatureMissing.into());
        }

        check_system_program(system_program_info.key)?;
        check_account_owner(payer_info, &system_program::id())?;
        check_account_owner(stake_pool_info, program_id)?;
        check_mpl_metadata_program(mpl_token_metadata_program_info.key)?;

        let stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        stake_pool.check_manager(manager_info)?;
        stake_pool.check_authority_withdraw(
            withdraw_authority_info.key,
            program_id,
            stake_pool_info.key,
        )?;
        stake_pool.check_mint(pool_mint_info)?;
        check_mpl_metadata_account_address(metadata_info.key, &stake_pool.pool_mint)?;

        // Token mint authority for stake-pool token is stake-pool withdraw authority
        let token_mint_authority = withdraw_authority_info;

        let new_metadata_instruction = create_metadata_accounts_v3(
            *mpl_token_metadata_program_info.key,
            *metadata_info.key,
            *pool_mint_info.key,
            *token_mint_authority.key,
            *payer_info.key,
            *token_mint_authority.key,
            name,
            symbol,
            uri,
        );

        let (_, stake_withdraw_bump_seed) =
            crate::find_withdraw_authority_program_address(program_id, stake_pool_info.key);

        let token_mint_authority_signer_seeds: &[&[_]] = &[
            stake_pool_info.key.as_ref(),
            AUTHORITY_WITHDRAW,
            &[stake_withdraw_bump_seed],
        ];

        invoke_signed(
            &new_metadata_instruction,
            &[
                metadata_info.clone(),
                pool_mint_info.clone(),
                withdraw_authority_info.clone(),
                payer_info.clone(),
                withdraw_authority_info.clone(),
                system_program_info.clone(),
            ],
            &[token_mint_authority_signer_seeds],
        )?;

        Ok(())
    }

    #[inline(never)]
    fn process_update_pool_token_metadata(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        name: String,
        symbol: String,
        uri: String,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();

        let stake_pool_info = next_account_info(account_info_iter)?;
        let manager_info = next_account_info(account_info_iter)?;
        let withdraw_authority_info = next_account_info(account_info_iter)?;
        let metadata_info = next_account_info(account_info_iter)?;
        let mpl_token_metadata_program_info = next_account_info(account_info_iter)?;

        check_account_owner(stake_pool_info, program_id)?;

        check_mpl_metadata_program(mpl_token_metadata_program_info.key)?;

        let stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        stake_pool.check_manager(manager_info)?;
        stake_pool.check_authority_withdraw(
            withdraw_authority_info.key,
            program_id,
            stake_pool_info.key,
        )?;
        check_mpl_metadata_account_address(metadata_info.key, &stake_pool.pool_mint)?;

        // Token mint authority for stake-pool token is withdraw authority only
        let token_mint_authority = withdraw_authority_info;

        let update_metadata_accounts_instruction = update_metadata_accounts_v2(
            *mpl_token_metadata_program_info.key,
            *metadata_info.key,
            *token_mint_authority.key,
            None,
            Some(DataV2 {
                name,
                symbol,
                uri,
                seller_fee_basis_points: 0,
                creators: None,
                collection: None,
                uses: None,
            }),
            None,
            Some(true),
        );

        let (_, stake_withdraw_bump_seed) =
            crate::find_withdraw_authority_program_address(program_id, stake_pool_info.key);

        let token_mint_authority_signer_seeds: &[&[_]] = &[
            stake_pool_info.key.as_ref(),
            AUTHORITY_WITHDRAW,
            &[stake_withdraw_bump_seed],
        ];

        invoke_signed(
            &update_metadata_accounts_instruction,
            &[metadata_info.clone(), withdraw_authority_info.clone()],
            &[token_mint_authority_signer_seeds],
        )?;

        Ok(())
    }

    /// Processes [`SetManager`](enum.Instruction.html).
    #[inline(never)] // needed to avoid stack size violation
    fn process_set_manager(program_id: &Pubkey, accounts: &[AccountInfo]) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let manager_info = next_account_info(account_info_iter)?;
        let new_manager_info = next_account_info(account_info_iter)?;
        let new_manager_fee_info = next_account_info(account_info_iter)?;

        check_account_owner(stake_pool_info, program_id)?;
        let mut stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        check_account_owner(new_manager_fee_info, &stake_pool.token_program_id)?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        stake_pool.check_manager(manager_info)?;
        if !new_manager_info.is_signer {
            msg!("New manager signature missing");
            return Err(StakePoolError::SignatureMissing.into());
        }

        stake_pool.check_manager_fee_info(new_manager_fee_info)?;

        stake_pool.manager = *new_manager_info.key;
        stake_pool.manager_fee_account = *new_manager_fee_info.key;
        borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)?;
        Ok(())
    }

    /// Processes [`SetFee`](enum.Instruction.html).
    #[inline(never)] // needed to avoid stack size violation
    fn process_set_fee(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        fee: FeeType,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let manager_info = next_account_info(account_info_iter)?;
        let clock = Clock::get()?;

        check_account_owner(stake_pool_info, program_id)?;
        let mut stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }
        stake_pool.check_manager(manager_info)?;

        if fee.can_only_change_next_epoch() && stake_pool.last_update_epoch < clock.epoch {
            return Err(StakePoolError::StakeListAndPoolOutOfDate.into());
        }

        fee.check_too_high()?;
        stake_pool.update_fee(&fee)?;
        borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)?;
        Ok(())
    }

    /// Processes [`SetStaker`](enum.Instruction.html).
    #[inline(never)] // needed to avoid stack size violation
    fn process_set_staker(program_id: &Pubkey, accounts: &[AccountInfo]) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let set_staker_authority_info = next_account_info(account_info_iter)?;
        let new_staker_info = next_account_info(account_info_iter)?;

        check_account_owner(stake_pool_info, program_id)?;
        let mut stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }

        let staker_signed = stake_pool.check_staker(set_staker_authority_info);
        let manager_signed = stake_pool.check_manager(set_staker_authority_info);
        if staker_signed.is_err() && manager_signed.is_err() {
            return Err(StakePoolError::SignatureMissing.into());
        }
        stake_pool.staker = *new_staker_info.key;
        borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)?;
        Ok(())
    }

    /// Processes [`SetFundingAuthority`](enum.Instruction.html).
    #[inline(never)] // needed to avoid stack size violation
    fn process_set_funding_authority(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        funding_type: FundingType,
    ) -> ProgramResult {
        let account_info_iter = &mut accounts.iter();
        let stake_pool_info = next_account_info(account_info_iter)?;
        let manager_info = next_account_info(account_info_iter)?;

        let new_authority = next_account_info(account_info_iter)
            .ok()
            .map(|new_authority_account_info| *new_authority_account_info.key);

        check_account_owner(stake_pool_info, program_id)?;
        let mut stake_pool = try_from_slice_unchecked::<StakePool>(&stake_pool_info.data.borrow())?;
        if !stake_pool.is_valid() {
            return Err(StakePoolError::InvalidState.into());
        }
        stake_pool.check_manager(manager_info)?;
        match funding_type {
            FundingType::StakeDeposit => {
                stake_pool.stake_deposit_authority = new_authority.unwrap_or(
                    find_deposit_authority_program_address(program_id, stake_pool_info.key).0,
                );
            }
            FundingType::SolDeposit => stake_pool.sol_deposit_authority = new_authority,
            FundingType::SolWithdraw => stake_pool.sol_withdraw_authority = new_authority,
        }
        borsh::to_writer(&mut stake_pool_info.data.borrow_mut()[..], &stake_pool)?;
        Ok(())
    }

    /// Process `WithdrawFromStakeAccountWithSession` instruction
    /// Withdraws lamports from a user stake account after cooldown.
    fn process_withdraw_from_stake_account_with_session(
        program_id: &Pubkey,
        accounts: &[AccountInfo],
        lamports: u64,
        user_stake_seed: u64,
    ) -> ProgramResult {
        use crate::USER_STAKE_SEED_PREFIX;
        use fogo_sessions_sdk::session::Session;

        let account_info_iter = &mut accounts.iter();
        let stake_account_info = next_account_info(account_info_iter)?;
        let recipient_info = next_account_info(account_info_iter)?;
        let clock_info = next_account_info(account_info_iter)?;
        let stake_history_info = next_account_info(account_info_iter)?;
        let signer_or_session_info = next_account_info(account_info_iter)?;

        let user_pubkey =
            Session::extract_user_from_signer_or_session(signer_or_session_info, program_id)?;

        if *recipient_info.key != user_pubkey {
            msg!("Recipient must be the session user wallet");
            return Err(ProgramError::InvalidAccountData);
        }

        // Validate stake account PDA
        let (expected_stake_pda, stake_pda_bump) = Pubkey::find_program_address(
            &[
                USER_STAKE_SEED_PREFIX,
                user_pubkey.as_ref(),
                &user_stake_seed.to_le_bytes(),
            ],
            program_id,
        );
        if expected_stake_pda != *stake_account_info.key {
            msg!("Invalid stake account PDA");
            return Err(ProgramError::InvalidSeeds);
        }

        // Verify stake account is deactivated and ready for withdrawal
        let stake_state = try_from_slice_unchecked::<stake::state::StakeStateV2>(
            &stake_account_info.data.borrow(),
        )?;

        let clock = Clock::get()?;

        match stake_state {
            stake::state::StakeStateV2::Stake(meta, stake, _) => {
                // Verify the stake's withdrawer is the PDA itself
                if meta.authorized.withdrawer != expected_stake_pda {
                    msg!(
                        "Stake withdrawer mismatch. Expected: {}, got: {}",
                        expected_stake_pda,
                        meta.authorized.withdrawer
                    );
                    return Err(ProgramError::InvalidAccountData);
                }

                // Check if stake is fully deactivated
                if stake.delegation.deactivation_epoch == Epoch::MAX {
                    msg!("Stake account is not deactivated yet");
                    return Err(StakePoolError::UserStakeNotActive.into());
                }
                if stake.delegation.deactivation_epoch >= clock.epoch {
                    msg!(
                        "Stake account not fully deactivated. Deactivation epoch: {}, current: {}",
                        stake.delegation.deactivation_epoch,
                        clock.epoch
                    );
                    return Err(StakePoolError::UserStakeNotActive.into());
                }
            }
            _ => {
                msg!("Stake account is not in staked state");
                return Err(StakePoolError::WrongStakeStake.into());
            }
        }

        let stake_balance = stake_account_info.lamports();

        // Determine withdrawal amount (u64::MAX means full withdrawal)
        let withdraw_amount = if lamports == u64::MAX {
            stake_balance
        } else {
            lamports
        };

        let stake_pda_seeds: &[&[u8]] = &[
            USER_STAKE_SEED_PREFIX,
            user_pubkey.as_ref(),
            &user_stake_seed.to_le_bytes(),
            &[stake_pda_bump],
        ];

        invoke_signed(
            &stake::instruction::withdraw(
                stake_account_info.key,
                stake_account_info.key,
                recipient_info.key,
                withdraw_amount,
                None,
            ),
            &[
                stake_account_info.clone(),
                recipient_info.clone(),
                clock_info.clone(),
                stake_history_info.clone(),
                stake_account_info.clone(),
            ],
            &[stake_pda_seeds],
        )?;

        Ok(())
    }

    /// Processes [`Instruction`](enum.Instruction.html).
    pub fn process(program_id: &Pubkey, accounts: &[AccountInfo], input: &[u8]) -> ProgramResult {
        let instruction = StakePoolInstruction::try_from_slice(input)?;
        match instruction {
            StakePoolInstruction::Initialize {
                fee,
                withdrawal_fee,
                deposit_fee,
                referral_fee,
                max_validators,
            } => {
                msg!("Instruction: Initialize stake pool");
                Self::process_initialize(
                    program_id,
                    accounts,
                    fee,
                    withdrawal_fee,
                    deposit_fee,
                    referral_fee,
                    max_validators,
                )
            }
            StakePoolInstruction::AddValidatorToPool(seed) => {
                msg!("Instruction: AddValidatorToPool");
                Self::process_add_validator_to_pool(program_id, accounts, seed)
            }
            StakePoolInstruction::RemoveValidatorFromPool => {
                msg!("Instruction: RemoveValidatorFromPool");
                Self::process_remove_validator_from_pool(program_id, accounts)
            }
            StakePoolInstruction::DecreaseValidatorStake {
                lamports,
                transient_stake_seed,
            } => {
                msg!("Instruction: DecreaseValidatorStake");
                msg!("NOTE: This instruction is deprecated, please use `DecreaseValidatorStakeWithReserve`");
                Self::process_decrease_validator_stake(
                    program_id,
                    accounts,
                    lamports,
                    transient_stake_seed,
                    None,
                    false,
                )
            }
            StakePoolInstruction::DecreaseValidatorStakeWithReserve {
                lamports,
                transient_stake_seed,
            } => {
                msg!("Instruction: DecreaseValidatorStakeWithReserve");
                Self::process_decrease_validator_stake(
                    program_id,
                    accounts,
                    lamports,
                    transient_stake_seed,
                    None,
                    true,
                )
            }
            StakePoolInstruction::DecreaseAdditionalValidatorStake {
                lamports,
                transient_stake_seed,
                ephemeral_stake_seed,
            } => {
                msg!("Instruction: DecreaseAdditionalValidatorStake");
                Self::process_decrease_validator_stake(
                    program_id,
                    accounts,
                    lamports,
                    transient_stake_seed,
                    Some(ephemeral_stake_seed),
                    true,
                )
            }
            StakePoolInstruction::IncreaseValidatorStake {
                lamports,
                transient_stake_seed,
            } => {
                msg!("Instruction: IncreaseValidatorStake");
                Self::process_increase_validator_stake(
                    program_id,
                    accounts,
                    lamports,
                    transient_stake_seed,
                    None,
                )
            }
            StakePoolInstruction::IncreaseAdditionalValidatorStake {
                lamports,
                transient_stake_seed,
                ephemeral_stake_seed,
            } => {
                msg!("Instruction: IncreaseAdditionalValidatorStake");
                Self::process_increase_validator_stake(
                    program_id,
                    accounts,
                    lamports,
                    transient_stake_seed,
                    Some(ephemeral_stake_seed),
                )
            }
            StakePoolInstruction::SetPreferredValidator {
                validator_type,
                validator_vote_address,
            } => {
                msg!("Instruction: SetPreferredValidator");
                Self::process_set_preferred_validator(
                    program_id,
                    accounts,
                    validator_type,
                    validator_vote_address,
                )
            }
            StakePoolInstruction::UpdateValidatorListBalance {
                start_index,
                no_merge,
            } => {
                msg!("Instruction: UpdateValidatorListBalance");
                Self::process_update_validator_list_balance(
                    program_id,
                    accounts,
                    start_index,
                    no_merge,
                )
            }
            StakePoolInstruction::UpdateStakePoolBalance => {
                msg!("Instruction: UpdateStakePoolBalance");
                Self::process_update_stake_pool_balance(program_id, accounts)
            }
            StakePoolInstruction::CleanupRemovedValidatorEntries => {
                msg!("Instruction: CleanupRemovedValidatorEntries");
                Self::process_cleanup_removed_validator_entries(program_id, accounts)
            }
            StakePoolInstruction::DepositStake => {
                msg!("Instruction: DepositStake");
                Self::process_deposit_stake(program_id, accounts, None)
            }
            StakePoolInstruction::WithdrawStake(amount) => {
                msg!("Instruction: WithdrawStake");
                Self::process_withdraw_stake(program_id, accounts, amount, None, None)
            }
            StakePoolInstruction::SetFee { fee } => {
                msg!("Instruction: SetFee");
                Self::process_set_fee(program_id, accounts, fee)
            }
            StakePoolInstruction::SetManager => {
                msg!("Instruction: SetManager");
                Self::process_set_manager(program_id, accounts)
            }
            StakePoolInstruction::SetStaker => {
                msg!("Instruction: SetStaker");
                Self::process_set_staker(program_id, accounts)
            }
            StakePoolInstruction::SetFundingAuthority(funding_type) => {
                msg!("Instruction: SetFundingAuthority");
                Self::process_set_funding_authority(program_id, accounts, funding_type)
            }
            StakePoolInstruction::DepositSol(lamports) => {
                msg!("Instruction: DepositSol");
                Self::process_deposit_sol(program_id, accounts, lamports, None, false)
            }
            StakePoolInstruction::WithdrawSol(pool_tokens) => {
                msg!("Instruction: WithdrawSol");
                Self::process_withdraw_sol(program_id, accounts, pool_tokens, None)
            }
            StakePoolInstruction::CreateTokenMetadata { name, symbol, uri } => {
                msg!("Instruction: CreateTokenMetadata");
                Self::process_create_pool_token_metadata(program_id, accounts, name, symbol, uri)
            }
            StakePoolInstruction::UpdateTokenMetadata { name, symbol, uri } => {
                msg!("Instruction: UpdateTokenMetadata");
                Self::process_update_pool_token_metadata(program_id, accounts, name, symbol, uri)
            }
            #[allow(deprecated)]
            StakePoolInstruction::Redelegate { .. } => {
                msg!("Instruction: Redelegate will not be enabled");
                Err(ProgramError::InvalidInstructionData)
            }
            StakePoolInstruction::DepositStakeWithSlippage {
                minimum_pool_tokens_out,
            } => {
                msg!("Instruction: DepositStakeWithSlippage");
                Self::process_deposit_stake(program_id, accounts, Some(minimum_pool_tokens_out))
            }
            StakePoolInstruction::WithdrawStakeWithSlippage {
                pool_tokens_in,
                minimum_lamports_out,
            } => {
                msg!("Instruction: WithdrawStakeWithSlippage");
                Self::process_withdraw_stake(
                    program_id,
                    accounts,
                    pool_tokens_in,
                    Some(minimum_lamports_out),
                    None,
                )
            }
            StakePoolInstruction::DepositSolWithSlippage {
                lamports_in,
                minimum_pool_tokens_out,
            } => {
                msg!("Instruction: DepositSolWithSlippage");
                Self::process_deposit_sol(
                    program_id,
                    accounts,
                    lamports_in,
                    Some(minimum_pool_tokens_out),
                    false,
                )
            }
            StakePoolInstruction::WithdrawSolWithSlippage {
                pool_tokens_in,
                minimum_lamports_out,
            } => {
                msg!("Instruction: WithdrawSolWithSlippage");
                Self::process_withdraw_sol(
                    program_id,
                    accounts,
                    pool_tokens_in,
                    Some(minimum_lamports_out),
                )
            }
            StakePoolInstruction::DepositWsolWithSession {
                lamports_in,
                minimum_pool_tokens_out,
            } => {
                msg!("Instruction: DepositWsolWithSession");
                Self::process_deposit_wsol_with_session(
                    program_id,
                    accounts,
                    lamports_in,
                    Some(minimum_pool_tokens_out),
                )
            }
            StakePoolInstruction::WithdrawWsolWithSession {
                pool_tokens_in,
                minimum_lamports_out,
            } => {
                msg!("Instruction: WithdrawWsolWithSession");
                Self::process_withdraw_wsol_with_session(
                    program_id,
                    accounts,
                    pool_tokens_in,
                    Some(minimum_lamports_out),
                )
            }
            StakePoolInstruction::WithdrawStakeWithSession {
                pool_tokens_in,
                minimum_lamports_out,
                user_stake_seed,
            } => {
                msg!("Instruction: WithdrawStakeWithSession");
                Self::process_withdraw_stake(
                    program_id,
                    accounts,
                    pool_tokens_in,
                    Some(minimum_lamports_out),
                    Some(user_stake_seed),
                )
            }
            StakePoolInstruction::WithdrawFromStakeAccountWithSession {
                lamports,
                user_stake_seed,
            } => {
                msg!("Instruction: WithdrawFromStakeAccountWithSession");
                Self::process_withdraw_from_stake_account_with_session(
                    program_id,
                    accounts,
                    lamports,
                    user_stake_seed,
                )
            }
        }
    }
}

impl PrintProgramError for StakePoolError {
    fn print<E>(&self)
    where
        E: 'static + std::error::Error + DecodeError<E> + PrintProgramError + FromPrimitive,
    {
        match self {
            StakePoolError::AlreadyInUse => msg!("Error: The account cannot be initialized because it is already being used"),
            StakePoolError::InvalidProgramAddress => msg!("Error: The program address provided doesn't match the value generated by the program"),
            StakePoolError::InvalidState => msg!("Error: The stake pool state is invalid"),
            StakePoolError::CalculationFailure => msg!("Error: The calculation failed"),
            StakePoolError::FeeTooHigh => msg!("Error: Stake pool fee > 1"),
            StakePoolError::WrongAccountMint => msg!("Error: Token account is associated with the wrong mint"),
            StakePoolError::WrongManager => msg!("Error: Wrong pool manager account"),
            StakePoolError::SignatureMissing => msg!("Error: Required signature is missing"),
            StakePoolError::InvalidValidatorStakeList => msg!("Error: Invalid validator stake list account"),
            StakePoolError::InvalidFeeAccount => msg!("Error: Invalid manager fee account"),
            StakePoolError::WrongPoolMint => msg!("Error: Specified pool mint account is wrong"),
            StakePoolError::WrongStakeStake => msg!("Error: Stake account is not in the state expected by the program"),
            StakePoolError::UserStakeNotActive => msg!("Error: User stake is not active"),
            StakePoolError::ValidatorAlreadyAdded => msg!("Error: Stake account voting for this validator already exists in the pool"),
            StakePoolError::ValidatorNotFound => msg!("Error: Stake account for this validator not found in the pool"),
            StakePoolError::InvalidStakeAccountAddress => msg!("Error: Stake account address not properly derived from the validator address"),
            StakePoolError::StakeListOutOfDate => msg!("Error: Identify validator stake accounts with old balances and update them"),
            StakePoolError::StakeListAndPoolOutOfDate => msg!("Error: First update old validator stake account balances and then pool stake balance"),
            StakePoolError::UnknownValidatorStakeAccount => {
                msg!("Error: Validator stake account is not found in the list storage")
            }
            StakePoolError::WrongMintingAuthority => msg!("Error: Wrong minting authority set for mint pool account"),
            StakePoolError::UnexpectedValidatorListAccountSize=> msg!("Error: The size of the given validator stake list does match the expected amount"),
            StakePoolError::WrongStaker=> msg!("Error: Wrong pool staker account"),
            StakePoolError::NonZeroPoolTokenSupply => msg!("Error: Pool token supply is not zero on initialization"),
            StakePoolError::StakeLamportsNotEqualToMinimum => msg!("Error: The lamports in the validator stake account is not equal to the minimum"),
            StakePoolError::IncorrectDepositVoteAddress => msg!("Error: The provided deposit stake account is not delegated to the preferred deposit vote account"),
            StakePoolError::IncorrectWithdrawVoteAddress => msg!("Error: The provided withdraw stake account is not the preferred deposit vote account"),
            StakePoolError::InvalidMintFreezeAuthority => msg!("Error: The mint has an invalid freeze authority"),
            StakePoolError::FeeIncreaseTooHigh => msg!("Error: The fee cannot increase by a factor exceeding the stipulated ratio"),
            StakePoolError::WithdrawalTooSmall => msg!("Error: Not enough pool tokens provided to withdraw 1-lamport stake"),
            StakePoolError::DepositTooSmall => msg!("Error: Not enough lamports provided for deposit to result in one pool token"),
            StakePoolError::InvalidStakeDepositAuthority => msg!("Error: Provided stake deposit authority does not match the program's"),
            StakePoolError::InvalidSolDepositAuthority => msg!("Error: Provided sol deposit authority does not match the program's"),
            StakePoolError::InvalidPreferredValidator => msg!("Error: Provided preferred validator is invalid"),
            StakePoolError::TransientAccountInUse => msg!("Error: Provided validator stake account already has a transient stake account in use"),
            StakePoolError::InvalidSolWithdrawAuthority => msg!("Error: Provided sol withdraw authority does not match the program's"),
            StakePoolError::SolWithdrawalTooLarge => msg!("Error: Too much SOL withdrawn from the stake pool's reserve account"),
            StakePoolError::InvalidMetadataAccount => msg!("Error: Metadata account derived from pool mint account does not match the one passed to program"),
            StakePoolError::UnsupportedMintExtension => msg!("Error: mint has an unsupported extension"),
            StakePoolError::UnsupportedFeeAccountExtension => msg!("Error: fee account has an unsupported extension"),
            StakePoolError::ExceededSlippage => msg!("Error: instruction exceeds desired slippage limit"),
            StakePoolError::IncorrectMintDecimals => msg!("Error: Provided mint does not have 9 decimals to match SOL"),
            StakePoolError::ReserveDepleted => msg!("Error: Pool reserve does not have enough lamports to fund rent-exempt reserve in split destination. Deposit more SOL in reserve, or pre-fund split destination with the rent-exempt reserve for a stake account."),
            StakePoolError::MissingRequiredSysvar => msg!("Missing required sysvar account"),
            StakePoolError::EpochRewardDistributionInProgress => msg!("Epoch reward distribution is currently in progress, stakes are still being updated"),
            StakePoolError::TooManyValidatorsInPool => msg!("The stake pool has too many validators in the pool"),
        }
    }
}