Struct ValidationObserver 

pub struct ValidationObserver {
    pub active: bool,
    pub sender: Address,
    pub deploy_frame_index: Option<usize>,
    pub current_frame_index: usize,
    pub current_frame_mode: u8,
    pub expiry_verifier: Address,
    pub canonical_paymaster_pay_frame: Option<usize>,
    pub last_opcode: u8,
    pub touched_sender_slots: Vec<H256>,
    pub violation: Option<FrameSimViolation>,
}

EIP-8141 validation-trace observer. Inert (active == false) in every VM construction except mempool prefix simulation.

The dispatch-loop and handler hooks read this only behind if self.validation_observer.active, so an inactive observer has zero overhead on the perf-sensitive execution path (one branch), exactly like LevmOpcodeTracer.

Fields

active: bool

Whether this observer is active. false disables every hook.

sender: Address

The frame transaction’s sender. SLOAD/SSTORE are restricted to this address; CALL/EXTCODE targets equal to this address are exempt.

deploy_frame_index: Option<usize>

Index (into FrameTransaction.frames) of the deploy frame, if the prefix has one. SSTORE/CREATE/CREATE2 are allowed only while this frame is executing.

current_frame_index: usize

Index of the currently executing prefix frame. Set by the harness before each frame runs.

current_frame_mode: u8

Execution mode of the currently executing prefix frame (raw mode byte: 0 = DEFAULT, 1 = VERIFY, 2 = SENDER). Set by the harness before each frame runs.

expiry_verifier: Address

Address of the canonical EXPIRY_VERIFIER predeploy (0x…8141). TIMESTAMP is permitted only when current_call_frame.code_address equals this value, which allows TIMESTAMP inside a nested call into the predeploy while correctly banning it in any callee of an expiry frame that routes execution elsewhere (an under-reject the per-top-frame boolean could not prevent).

canonical_paymaster_pay_frame: Option<usize>

Index of the canonical paymaster’s pay frame, if any. Always None (OQ1, see module docs); the access-restriction skip is wired for the future canonical-paymaster case.

last_opcode: u8

The opcode byte executed on the previous dispatch-loop iteration. Used to enforce the GAS sequential rule (GAS is allowed only immediately before a *CALL). Reset each iteration.

touched_sender_slots: Vec<H256>

Sender storage slots touched (read or written) during the prefix. Recorded for the admission-time revalidation affected-set (Phase 3).

violation: Option<FrameSimViolation>

First violation observed, if any.

Implementations

impl ValidationObserver

pub fn disabled() -> Self

Returns an inactive observer. No allocations; zero overhead on the hot path (every hook is gated by if active).

pub fn new( sender: Address, deploy_frame_index: Option<usize>, expiry_verifier: Address, ) -> Self

Returns an active observer for simulating the validation prefix of a frame transaction sent by sender, whose deploy frame (if any) is at deploy_frame_index.

pub fn record_violation(&mut self, violation: FrameSimViolation)

Records the first violation observed; later violations are ignored (the transaction is already rejected).

pub fn in_canonical_pay_frame(&self) -> bool

Whether the currently executing frame is the canonical paymaster pay frame (always false while canonical_paymaster_pay_frame is None).

pub fn in_deploy_frame(&self) -> bool

Whether the currently executing frame is the deploy frame.

Trait Implementations

impl Clone for ValidationObserver

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ValidationObserver

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.