Module check 

Multi-tier validation system.

Hopper supports five validation levels:

1. Account-local: owner, signer, writable, size, discriminator, layout_id
2. Cross-account: vault.mint == mint.address(), authority matches
3. State-transition: status enum transitions, balance bounds
4. CPI composition: post-CPI invariants, no-CPI guards
5. Post-mutation: balance conservation, solvency invariants (via PostMutationValidator)

Validation can be composed with named groups (ValidationGroup), instruction-specific rule packs (TransitionRulePack), and multi-group bundles (ValidationBundle).

Modules

fast

Batched u32 header validation using a single-compare optimization.

graph

Composable Validation Pipeline.

guards

Security guard packs – safe-by-default exploit prevention.

modifier

Modifier-style composable account wrappers.

trust

Foreign-account trust profiles.

Structs

InstructionAccountMeta

Account meta decoded from an Instructions sysvar entry.

InstructionsSysvar

Typed borrowed view over the Instructions sysvar account data.

IntrospectedInstruction

Typed borrowed view over one instruction inside the Instructions sysvar.

Functions

check_account

Combined account check: owner + discriminator + minimum size.

check_accounts_unique

Check that two accounts are unique (different addresses).

check_accounts_unique_3

Check that three accounts are all unique.

check_address

Check an account’s address matches an expected value.

check_discriminator

Check that the discriminator byte matches.

check_executable

Check that an account is executable (a program).

check_has_one

Check has_one: a stored address in account data matches another account’s address.

check_instruction_data_min

Check instruction data meets minimum length.

check_keys_eq

Check that two account addresses are equal.

check_lamports_gte

Check that the account has at least min lamports.

check_no_subsequent_invocation

Ensure our program is not invoked after the current instruction.

check_not_closed

Check that an account has not been closed (no close sentinel).

check_owner

Check that an account is owned by the expected program.

check_owner_multi

Check that an account is owned by one of the given program IDs.

check_program

Check that an account is a specific program: its key matches expected_program_id and it is flagged executable.

check_rent_exempt

Check that an account is rent exempt.

check_signer

Check that an account is a signer.

check_size

Check minimum data size.

check_system_program

System program check.

check_uninitialized

Check uninitialized: account data is empty.

check_writable

Check that an account is writable.

current_instruction_index

Read the current instruction index from the Instructions sysvar.

detect_flash_loan_bracket

Detect flash-loan bracket: same program called before AND after current.

find_and_verify_pda

Find a PDA and verify it matches the account, returning the bump.

instruction_count

Read the number of instructions in the current transaction.

is_zero_address

Check if a 32-byte address is all zeros (the default/system address).

keys_eq_fast

Fast 32-byte key equality check using 4x u64 comparisons.

read_program_id_at

Read the program_id of instruction at the given index.

rent_exempt_min

Rent-exempt minimum lamports for a given data size.

require_top_level

Require that the current instruction is top-level (not a CPI).

verify_pda

Verify a PDA with bump, using the cheap create_program_address path.

verify_pda_cached

Verify a PDA by reading the bump from account data at a known offset.