hpsvm 0.2.1

//! Commit-delta logic for applying detached execution outcomes to the VM state.
//!
//! This module encapsulates the delta plumbing: constructing a [`CommitDelta`]
//! from a detached execution outcome and applying the delta to accounts and
//! transaction history. Staged execution (`ExecutedTx`) applies the account
//! half eagerly at `transact` time and records the history half at `commit`
//! time; the parallel batch path still funnels worker outcomes through
//! [`detached_into_result_and_delta`] + [`apply_commit_delta`].

use solana_account::AccountSharedData;
use solana_address::Address;
use solana_signature::Signature;

use crate::{
    StateChangeSet,
    accounts_db::AccountsDb,
    error::HPSVMError,
    executed::DetachedTx,
    history::TransactionHistory,
    types::{FailedTransactionMetadata, TransactionResult},
};

/// Split result of a commit delta.
type CommitDeltaParts = (Vec<(Address, AccountSharedData)>, Option<(Signature, TransactionResult)>);

/// A self-contained set of mutations produced by a single transaction execution.
///
/// Staged execution (`transact` → `commit`/`discard`) and the parallel batch
/// merge share this type: the batch path builds one per worker transaction and
/// applies them in stage order.
#[derive(Debug, Clone)]
pub(crate) struct CommitDelta {
    post_accounts: Vec<(Address, AccountSharedData)>,
    history_entry: Option<(Signature, TransactionResult)>,
}

impl CommitDelta {
    pub(crate) const fn new(
        post_accounts: Vec<(Address, AccountSharedData)>,
        history_entry: Option<(Signature, TransactionResult)>,
    ) -> Self {
        Self { post_accounts, history_entry }
    }

    pub(crate) const fn mutates_state(&self) -> bool {
        !self.post_accounts.is_empty() || self.history_entry.is_some()
    }

    /// Splits the delta into its account writes and its history entry.
    ///
    /// The staged path syncs the accounts eagerly and keeps the entry for
    /// commit time.
    pub(crate) fn into_parts(self) -> CommitDeltaParts {
        (self.post_accounts, self.history_entry)
    }
}

/// Apply a commit delta to the VM's account store and transaction history.
///
/// # Errors
///
/// Returns [`HPSVMError`] if writing accounts fails (e.g. invalid sysvar data).
pub(crate) fn apply_commit_delta(
    accounts: &mut AccountsDb,
    history: &mut TransactionHistory,
    set: impl Into<StateChangeSet>,
) -> Result<(), HPSVMError> {
    let set = set.into();
    accounts.sync_accounts(set.post_accounts)?;
    if let Some((signature, entry)) = set.history_entry {
        history.add_new_transaction(signature, entry);
    }
    Ok(())
}

impl From<CommitDelta> for StateChangeSet {
    fn from(delta: CommitDelta) -> Self {
        let (post_accounts, history_entry) = delta.into_parts();
        Self { post_accounts, history_entry }
    }
}

impl From<StateChangeSet> for CommitDelta {
    fn from(set: StateChangeSet) -> Self {
        Self::new(set.post_accounts, set.history_entry)
    }
}

/// Decompose a [`DetachedTx`] into its transaction result and the
/// corresponding commit delta.
///
/// When `history_enabled` is `false`, no transaction-history entry is built,
/// which lets the metadata move into the returned result instead of being
/// cloned. This keeps the steady-state hot path (history disabled) free of the
/// two `TransactionMetadata` clones the previous implementation performed per
/// transaction.
pub(crate) fn detached_into_result_and_delta(
    detached: DetachedTx,
    history_enabled: bool,
) -> (TransactionResult, CommitDelta) {
    let DetachedTx { meta, post_accounts, status, included, .. } = detached;
    let signature = meta.signature;
    // Move `meta` into the result instead of cloning it.
    let result = match status {
        Ok(()) => TransactionResult::Ok(meta),
        Err(err) => TransactionResult::Err(FailedTransactionMetadata { err, meta }),
    };
    let delta = if included {
        // Only clone the full result when history is actually going to store it.
        let history_entry = history_enabled.then(|| (signature, result.clone()));
        CommitDelta::new(post_accounts, history_entry)
    } else {
        CommitDelta::new(Vec::new(), None)
    };
    (result, delta)
}

/// Decompose a [`DetachedTx`] into its transaction result and the
/// corresponding state change set.
#[inline]
pub(crate) fn detached_into_result_and_state_change_set(
    detached: DetachedTx,
    history_enabled: bool,
) -> (TransactionResult, StateChangeSet) {
    let (result, delta) = detached_into_result_and_delta(detached, history_enabled);
    (result, StateChangeSet::from(delta))
}

#[cfg(test)]
mod tests {
    use proptest::prelude::*;
    use solana_account::Account;
    use solana_address::Address;
    use solana_signature::Signature;
    use solana_transaction_error::TransactionError;

    use super::*;
    use crate::{Hpsvm, types::TransactionMetadata};

    fn detached_with(
        status: Result<(), TransactionError>,
        included: bool,
        post_accounts: Vec<(Address, AccountSharedData)>,
    ) -> DetachedTx {
        let signature = Signature::from([7; 64]);
        DetachedTx {
            meta: TransactionMetadata { signature, ..Default::default() },
            post_accounts,
            status,
            included,
            fee_payer: Some(Address::new_unique()),
            fatal_error: None,
            inspector_live: false,
        }
    }

    fn account(lamports: u64) -> AccountSharedData {
        AccountSharedData::new(lamports, 0, &Address::new_unique())
    }

    // -----------------------------------------------------------------
    // CommitDelta
    // -----------------------------------------------------------------

    #[test]
    fn an_empty_delta_does_not_mutate_state() {
        assert!(!CommitDelta::new(Vec::new(), None).mutates_state());
    }

    #[test]
    fn a_delta_with_post_accounts_mutates_state() {
        let delta = CommitDelta::new(vec![(Address::new_unique(), account(1))], None);
        assert!(delta.mutates_state());
    }

    #[test]
    fn a_delta_with_only_a_history_entry_mutates_state() {
        let delta = CommitDelta::new(
            Vec::new(),
            Some((Signature::from([1; 64]), TransactionResult::Ok(TransactionMetadata::default()))),
        );
        assert!(delta.mutates_state());
    }

    // -----------------------------------------------------------------
    // detached_into_result_and_delta
    // -----------------------------------------------------------------

    #[test]
    fn a_successful_detached_outcome_moves_the_metadata_into_the_result() {
        let outcome = detached_with(Ok(()), true, vec![(Address::new_unique(), account(1))]);
        let (result, delta) = detached_into_result_and_delta(outcome, false);

        assert!(result.is_ok());
        assert_eq!(delta.post_accounts.len(), 1);
        // History disabled: no entry is built at all.
        assert!(delta.history_entry.is_none());
        assert!(delta.mutates_state());
    }

    #[test]
    fn a_failed_detached_outcome_produces_failed_metadata() {
        let outcome = detached_with(
            Err(TransactionError::AccountNotFound),
            true,
            vec![(Address::new_unique(), account(1))],
        );
        let (result, delta) = detached_into_result_and_delta(outcome, true);

        match result {
            TransactionResult::Err(meta) => {
                assert!(matches!(meta.err, TransactionError::AccountNotFound));
            }
            other => panic!("expected TransactionResult::Err, got {}", is_ok(&other)),
        }
        assert!(delta.history_entry.is_some());
    }

    /// An excluded outcome is not eligible for commit-time side effects, so its
    /// post accounts must be discarded rather than applied.
    #[test]
    fn an_excluded_detached_outcome_discards_its_post_accounts() {
        let outcome = detached_with(Ok(()), false, vec![(Address::new_unique(), account(1))]);
        let (result, delta) = detached_into_result_and_delta(outcome, true);

        assert!(result.is_ok());
        assert!(delta.post_accounts.is_empty());
        assert!(delta.history_entry.is_none());
        assert!(!delta.mutates_state());
    }

    /// With history enabled the result is cloned so both the caller and the
    /// history hold the same value.
    #[test]
    fn an_included_detached_outcome_with_history_enabled_records_an_entry() {
        let outcome = detached_with(Ok(()), true, Vec::new());
        let (result, delta) = detached_into_result_and_delta(outcome, true);

        let (signature, stored) = delta.history_entry.clone().expect("history entry must be built");
        assert_eq!(signature, Signature::from([7; 64]));
        assert_eq!(stored, result);
        assert!(delta.mutates_state());
    }

    /// With history disabled the metadata must move (not be cloned) into the
    /// result, and no entry may be built.
    #[test]
    fn an_included_detached_outcome_with_history_disabled_records_no_entry() {
        let outcome = detached_with(Ok(()), true, Vec::new());
        let (result, delta) = detached_into_result_and_delta(outcome, false);

        assert!(delta.history_entry.is_none());
        assert!(!delta.mutates_state());
        assert!(result.is_ok());
    }

    // Property: `included` alone decides whether post accounts survive, and
    // `history_enabled` alone decides whether an entry is built.
    proptest! {
        #[test]
        fn included_and_history_enabled_independently_control_the_delta(
            included in any::<bool>(),
            history_enabled in any::<bool>(),
            lamports in any::<u64>(),
        ) {
            let post_accounts = vec![(Address::new_unique(), account(lamports))];
            let outcome = detached_with(Ok(()), included, post_accounts);
            let (_, delta) = detached_into_result_and_delta(outcome, history_enabled);

            prop_assert_eq!(delta.post_accounts.is_empty(), !included);
            prop_assert_eq!(delta.history_entry.is_some(), included && history_enabled);
            prop_assert_eq!(delta.mutates_state(), included);
        }
    }

    // Property: the result and any stored history entry are always equal, for
    // both success and failure statuses.
    proptest! {
        #[test]
        fn the_history_entry_always_mirrors_the_result(
            included in any::<bool>(),
            history_enabled in any::<bool>(),
            fails in any::<bool>(),
        ) {
            let status = if fails { Err(TransactionError::AlreadyProcessed) } else { Ok(()) };
            let outcome = detached_with(status, included, Vec::new());
            let (result, delta) = detached_into_result_and_delta(outcome, history_enabled);

            match delta.history_entry {
                Some((_, stored)) => prop_assert_eq!(stored, result),
                None => prop_assert!(!(included && history_enabled)),
            }
        }
    }

    // -----------------------------------------------------------------
    // apply_commit_delta
    // -----------------------------------------------------------------

    #[test]
    fn applying_a_delta_writes_post_accounts() {
        let mut svm = Hpsvm::new();
        let address = Address::new_unique();

        let delta = CommitDelta::new(
            vec![(address, AccountSharedData::new(123, 0, &solana_sdk_ids::system_program::id()))],
            None,
        );
        apply_commit_delta(&mut svm.accounts, &mut svm.history, delta).unwrap();

        assert_eq!(svm.get_balance(&address), Some(123));
    }

    #[test]
    fn applying_a_delta_records_the_history_entry() {
        let mut svm = Hpsvm::new();
        let signature = Signature::from([9; 64]);

        let delta = CommitDelta::new(
            Vec::new(),
            Some((signature, TransactionResult::Ok(TransactionMetadata::default()))),
        );
        apply_commit_delta(&mut svm.accounts, &mut svm.history, delta).unwrap();

        assert!(svm.history.check_transaction(&signature));
        assert!(svm.history.get_transaction(&signature).is_some());
    }

    #[test]
    fn applying_an_empty_delta_is_a_no_op() {
        let mut svm = Hpsvm::new();
        apply_commit_delta(&mut svm.accounts, &mut svm.history, CommitDelta::new(Vec::new(), None))
            .unwrap();
    }

    /// A disabled history must silently drop the entry rather than storing it.
    #[test]
    fn applying_a_delta_with_a_disabled_history_drops_the_entry() {
        let mut svm = Hpsvm::new();
        svm.set_transaction_history(0);
        let signature = Signature::from([9; 64]);

        let delta = CommitDelta::new(
            Vec::new(),
            Some((signature, TransactionResult::Ok(TransactionMetadata::default()))),
        );
        apply_commit_delta(&mut svm.accounts, &mut svm.history, delta).unwrap();

        assert!(!svm.history.is_enabled());
        assert!(!svm.history.check_transaction(&signature));
    }

    /// A write into a sysvar slot with malformed data must surface as an error
    /// rather than silently corrupting the sysvar.
    #[test]
    fn applying_a_sysvar_account_with_invalid_data_is_rejected() {
        let mut svm = Hpsvm::new();
        let sysvar = solana_sdk_ids::sysvar::clock::id();

        let broken = Account {
            lamports: 1,
            data: vec![0xff; 7],
            owner: sysvar,
            executable: false,
            rent_epoch: 0,
        };

        let error = apply_commit_delta(
            &mut svm.accounts,
            &mut svm.history,
            CommitDelta::new(vec![(sysvar, AccountSharedData::from(broken))], None),
        )
        .expect_err("a malformed sysvar must be rejected");
        assert!(matches!(error, crate::error::HPSVMError::InvalidSysvarData(_)), "got {error:?}");
    }

    /// A valid sysvar account must be accepted and take effect.
    #[test]
    fn applying_a_valid_sysvar_account_succeeds() {
        let mut svm = Hpsvm::new();
        let sysvar = solana_sdk_ids::sysvar::clock::id();
        // Round-trip the existing sysvar account so the payload is well formed.
        let existing =
            svm.get_account(&sysvar).expect("a fresh VM must have a clock sysvar account");

        apply_commit_delta(
            &mut svm.accounts,
            &mut svm.history,
            CommitDelta::new(vec![(sysvar, AccountSharedData::from(existing))], None),
        )
        .expect("a valid clock sysvar must be accepted");

        let expected = svm.block_env().slot;
        let clock: solana_clock::Clock = svm.get_sysvar();
        assert_eq!(clock.slot, expected, "the sysvar must survive the delta");
    }

    /// A non-sysvar account is written without any validation.
    #[test]
    fn applying_a_non_sysvar_account_is_never_validated() {
        let mut svm = Hpsvm::new();
        let address = Address::new_unique();
        let account = Account {
            lamports: 9,
            data: vec![0xff; 3],
            owner: Address::new_unique(),
            executable: false,
            rent_epoch: 0,
        };

        apply_commit_delta(
            &mut svm.accounts,
            &mut svm.history,
            CommitDelta::new(vec![(address, AccountSharedData::from(account))], None),
        )
        .expect("a regular account must be accepted");

        assert_eq!(svm.get_balance(&address), Some(9));
    }

    fn is_ok(result: &TransactionResult) -> bool {
        result.is_ok()
    }

    // Property: change sets produced from disjoint workers commute when merged
    // in either order, because their address sets do not overlap.
    proptest! {
        #[test]
        fn disjoint_state_change_sets_commute_when_merged(
            g0 in any::<u8>(),
            g1 in any::<u8>(),
            g2 in any::<u8>(),
            g3 in any::<u8>(),
            l0 in any::<u64>(),
            l1 in any::<u64>(),
            l2 in any::<u64>(),
            l3 in any::<u64>(),
        ) {
            use crate::accounts_db::AccountsDb;
            use crate::history::TransactionHistory;

            let addrs = [Address::new_unique(), Address::new_unique(), Address::new_unique(), Address::new_unique()];
            let lamports = [l0, l1, l2, l3];
            let groups = [g0, g1, g2, g3];
            let mut a_accounts = Vec::new();
            let mut b_accounts = Vec::new();
            for i in 0..4 {
                let owner = Address::new_unique();
                let account = AccountSharedData::new(lamports[i], 0, &owner);
                match groups[i] % 2 {
                    0 => a_accounts.push((addrs[i], account)),
                    _ => b_accounts.push((addrs[i], account)),
                }
            }

            let set_a = StateChangeSet { post_accounts: a_accounts, history_entry: None };
            let set_b = StateChangeSet { post_accounts: b_accounts, history_entry: None };

            let mut db1 = AccountsDb::default();
            let mut hist1 = TransactionHistory::new();
            apply_commit_delta(&mut db1, &mut hist1, set_a.clone()).unwrap();
            apply_commit_delta(&mut db1, &mut hist1, set_b.clone()).unwrap();

            let mut db2 = AccountsDb::default();
            let mut hist2 = TransactionHistory::new();
            apply_commit_delta(&mut db2, &mut hist2, set_b).unwrap();
            apply_commit_delta(&mut db2, &mut hist2, set_a).unwrap();

            for addr in &addrs {
                prop_assert_eq!(db1.get_account(addr), db2.get_account(addr));
            }
        }
    }
}