test(fast-inbox): stub parent-checkpoint sourcing for the inbox rolling hash (A-1373)

The proposal handler, sequencer job, and prover node now source the parent
checkpoint's inboxRollingHash. Serve zeroed parent headers from the mocks so
scenarios beyond the genesis checkpoint resolve their chain start: the
validator suite stubs the proposed-checkpoint fallback (getCheckpointData
doubles as the already-published existence check), the sequencer suite stubs
getCheckpointData, and the prover-node suite serves synthetic ancestors below
the mined window.

Author: spalladino

yarn-project/prover-node/src/prover-node.test.ts

@@ -723,7 +723,7 @@ describe('ProverNode', () => {
   ): Checkpoint {
     return {
       number: CheckpointNumber(checkpointNumber),
-      header: { slotNumber: SlotNumber(slot) },
+      header: { slotNumber: SlotNumber(slot), inboxRollingHash: Fr.ZERO },
       archive: { root: archiveRoot },
       blocks: [{ number: blockNumber, header: { hash: () => Promise.resolve('0x01') } }],
       hash: () => new Fr(checkpointNumber),
@@ -745,9 +745,19 @@ describe('ProverNode', () => {
    */
   function mineCheckpoint(checkpoint: Checkpoint): L2BlockStreamEvent {
     mined.set(Number(checkpoint.number), checkpoint);
-    l2BlockSource.getCheckpoint.mockImplementation((query: any) =>
-      Promise.resolve('number' in query ? makeMaybePublished(mined.get(Number(query.number))) : undefined),
-    );
+    l2BlockSource.getCheckpoint.mockImplementation((query: any) => {
+      if (!('number' in query)) {
+        return Promise.resolve(undefined);
+      }
+      const number = Number(query.number);
+      const found = mined.get(number);
+      // Ancestors below the mined window exist on chain but are irrelevant to the scenario; serve a synthetic
+      // parent so inbox rolling-hash sourcing for the earliest mined checkpoint resolves.
+      const belowWindow = number > 0 && number < Math.min(...mined.keys());
+      return Promise.resolve(
+        makeMaybePublished(found ?? (belowWindow ? makeCheckpoint(number, number, number) : undefined)),
+      );
+    });
     l2BlockSource.getCheckpointsData.mockImplementation((query: any) => {
       if (!('from' in query)) {
         return Promise.resolve([]);

yarn-project/sequencer-client/src/sequencer/checkpoint_proposal_job.test.ts

@@ -249,6 +249,11 @@ describe('CheckpointProposalJob', () => {
 
     l2BlockSource = mock<L2BlockSource>();
     l2BlockSource.getCheckpointsData.mockResolvedValue([]);
+    // The job sources the parent checkpoint's inboxRollingHash; serve an empty parent header so jobs beyond
+    // the genesis checkpoint resolve their chain start.
+    l2BlockSource.getCheckpointData.mockImplementation(query =>
+      Promise.resolve('number' in query ? ({ header: CheckpointHeader.empty() } as CheckpointData) : undefined),
+    );
     // The (always-on) pipelined submission path waits for the archiver to confirm the parent
     // checkpoint on L1 before enqueuing the proposal. For the default job (checkpoint 1, no
     // proposed parent), the parent is genesis (cp 0), so a synced archiver reporting a

yarn-project/validator-client/src/validator.test.ts

@@ -30,10 +30,11 @@ import {
 import { OffenseType, WANT_TO_CLEAR_SLASH_EVENT, WANT_TO_SLASH_EVENT } from '@aztec/slasher';
 import { AztecAddress } from '@aztec/stdlib/aztec-address';
 import { type BlockData, BlockHash, L2Block, type L2BlockSink, type L2BlockSource } from '@aztec/stdlib/block';
-import { type Checkpoint, CheckpointReexecutionTracker } from '@aztec/stdlib/checkpoint';
+import { type Checkpoint, CheckpointReexecutionTracker, type ProposedCheckpointData } from '@aztec/stdlib/checkpoint';
 import type { SlasherConfig, WorldStateSynchronizer } from '@aztec/stdlib/interfaces/server';
 import { type L1ToL2MessageSource, computeInHashFromL1ToL2Messages } from '@aztec/stdlib/messaging';
 import type { BlockProposal } from '@aztec/stdlib/p2p';
+import { CheckpointHeader } from '@aztec/stdlib/rollup';
 import {
   TEST_COORDINATION_SIGNATURE_CONTEXT,
   makeBlockHeader,
@@ -166,6 +167,15 @@ describe('ValidatorClient', () => {
     blockSource.getBlocksForSlot.mockResolvedValue([]);
     blockSource.getSyncedL2SlotNumber.mockResolvedValue(SlotNumber(Number.MAX_SAFE_INTEGER));
     blockSource.syncImmediate.mockResolvedValue(undefined);
+    // The proposal handler sources the parent checkpoint's inboxRollingHash from the block source; serve an
+    // empty (all-zero) parent header from the proposed-checkpoint fallback so proposals beyond the genesis
+    // checkpoint resolve their chain start. getCheckpointData stays undefined: the checkpoint-proposal path
+    // uses it as an already-published-on-L1 existence check.
+    blockSource.getProposedCheckpointData.mockImplementation(query =>
+      Promise.resolve(
+        query && 'number' in query ? ({ header: CheckpointHeader.empty() } as ProposedCheckpointData) : undefined,
+      ),
+    );
     epochCache.isEscapeHatchOpenAtSlot.mockResolvedValue(false);
     l1ToL2MessageSource = mock<L1ToL2MessageSource>();
     txProvider = mock<TxProvider>();