Module graph 

Composable Validation Pipeline.

Three layers of validation composition:

1. Atomic rules – fn pointers and closures (combinators). ValidationGraph stores fn pointers for static rule sets. require_signer_at() and friends return closures for inline use.

2. Named groups and bundles – ValidationGroup bundles related rules under a label for reuse. ValidationBundle composes groups into a single check. TransitionRulePack dispatches rules by instruction tag.

3. Post-mutation checks – PostMutationValidator holds checks that run after account writes. Balance conservation, solvency invariants, authority immutability – anything that needs the final state to verify.

AccountConstraint and TransactionConstraint provide builder-pattern validation for single accounts and global instruction-level checks.

// Named group for reuse across instructions:
let mut signer_checks = ValidationGroup::<2>::new("signer_checks");
signer_checks.add(validate_authority)?;
signer_checks.add(validate_fee_payer)?;

// Bundle groups together:
let mut bundle = ValidationBundle::<2>::new();
bundle.add(&signer_checks)?;
bundle.add(&tx_constraint)?;
bundle.run(&ctx)?;

// Instruction-specific rules:
let mut rules = TransitionRulePack::<8>::new();
rules.add(0, validate_init)?;
rules.add(1, validate_deposit)?;
rules.run_for(instruction_tag, &ctx)?;

// Post-mutation invariants:
let mut post = PostMutationValidator::<2>::new();
post.add(check_vault_solvent)?;
post.run(accounts, program_id)?;

Structs

AccountConstraint

A builder for constructing validation constraints on a single account.

PostMutationValidator

Collects post-mutation checks that run after instruction execution.

TransactionConstraint

Transaction-level constraint that validates global properties.

TransitionRulePack

Associates validation rules with specific instruction tags.

ValidationBundle

A bundle that composes multiple ValidationGroups into a single check.

ValidationContext

Context passed to each validation node.

ValidationGraph

A stack-allocated validation graph with up to N nodes.

ValidationGroup

A named group of validation rules.

Traits

Validatable

Trait for validation runnables (groups and graphs).

Functions

require_all_unique_accounts

Validate that all account addresses are unique.

require_data_min

Validate minimum instruction data length.

require_keys_equal

Validate two accounts have the same key (e.g., stored address == provided account).

require_lamports_gte

Validate that an account has at least min lamports.

require_owned_at

Validate that a specific account is owned by the program.

require_signer_at

Validate that a specific account is a signer.

require_unique

Validate two accounts are different (no duplicates).

require_unique_signer_accounts

Validate that no duplicated account is used as a signer.

require_unique_writable_accounts

Validate that no duplicated account is writable.

require_writable_at

Validate that a specific account is writable.

Type Aliases

InstructionTag

Instruction dispatch tag for associating validation rules with specific instructions.

PostMutationFn

Signature for a post-mutation check function.

ValidateFn

A validation function signature.