Module guards 

Validation guards for Hopper programs.

These functions define the “sentence structure” of Hopper handlers. They support the canonical authored flow:

Validate -> Load -> Mutate -> Emit

Each guard reads as a clear, auditable assertion. Functions return ProgramResult (i.e. Result<(), ProgramError>) so they compose naturally with ?.

use hopper::prelude::*;

fn deposit(ctx: &Context, amount: u64) -> ProgramResult {
    let authority = ctx.account(0)?;
    let vault = ctx.account(1)?;

    require_signer(authority)?;
    require_writable(vault)?;
    require_disc(vault, 1)?;
    require_owner(vault, ctx.program_id)?;

    let state = vault.load_mut::<VaultState>()?;
    // ...
    Ok(())
}

Functions

require

Require a boolean condition, returning err if false.

require_address

Require that the account has the given address.

require_data_len

Require the account has at least min_len bytes of data.

require_disc

Require the account has the given discriminator byte.

require_eq

Require two values to be equal.

require_gt

Require a > b.

require_gte

Require a >= b.

require_has_data

Require the account has non-empty data.

require_keys_eq

Require two addresses to be equal.

require_keys_neq

Require two addresses to be different.

require_layout

Require the account passes a full layout contract check (disc + version + layout_id).

require_neq

Require two values to be different.

require_owner

Require that the account is owned by the given program.

require_payer

Require both signer and writable (common payer pattern).

require_signer

Require that the account signed the transaction.

require_unique_2

Require that n accounts are different (pairwise uniqueness, up to 6).

require_unique_3

Require 3 accounts are pairwise unique.

require_version

Require the account’s version byte matches the layout contract’s VERSION.

require_writable

Require that the account is writable.