fix(fast-inbox): override the pipelined parent's consumed inbox total in propose simulation (A-1384)

`ProposeLib.validateInboxConsumption` reads the parent checkpoint's recorded `inboxMsgTotal` and
caps `bucket.totalMsgCount - parentTotal` at the per-checkpoint limit. When the sequencer simulates
a propose against a parent that is proposed but not yet mined, the parent has no temp-checkpoint-log
cell on L1, so that total read as zero and the consumed count came out as the Inbox's entire
history — a spurious `Rollup__TooManyInboxMessagesConsumed` revert once the Inbox has accumulated
more than one checkpoint's cap of messages. Carry the total on `ProposedCheckpointData` (derived by
the archiver from the checkpoint's last block L1-to-L2 leaf count, which is what `propose` records)
and feed it into the pending temp-log override alongside the slot number it shares a word with.

Author: spalladino

yarn-project/archiver/src/archiver-store.test.ts

@@ -462,6 +462,7 @@ describe('Archiver Store', () => {
         totalManaUsed: 100n,
         feeAssetPriceModifier: 0n,
       });
+      return block;
     }
 
     it('returns the latest proposed entry when called with no args', async () => {
@@ -477,6 +478,13 @@ describe('Archiver Store', () => {
       expect(result).toBeUndefined();
     });
 
+    it('reports the consumed Inbox total of the last block in the checkpoint', async () => {
+      const block = await addProposedCheckpoint(CheckpointNumber(1), SlotNumber(3), BlockNumber(1));
+
+      const result = await archiver.getProposedCheckpointData();
+      expect(result!.inboxMsgTotal).toBe(BigInt(block.header.state.l1ToL2MessageTree.nextAvailableLeafIndex));
+    });
+
     it('returns the latest proposed entry for tag=proposed', async () => {
       await addProposedCheckpoint(CheckpointNumber(1), SlotNumber(5), BlockNumber(1));
 

yarn-project/archiver/src/store/block_store.ts

@@ -125,6 +125,7 @@ type CheckpointStorage = CommonCheckpointStorage & {
 type ProposedCheckpointStorage = CommonCheckpointStorage & {
   totalManaUsed: string;
   feeAssetPriceModifier: string;
+  inboxMsgTotal: string;
 };
 
 export type RemoveCheckpointsResult = { blocksRemoved: L2Block[] | undefined };
@@ -930,6 +931,7 @@ export class BlockStore {
       blockCount: stored.blockCount,
       totalManaUsed: BigInt(stored.totalManaUsed),
       feeAssetPriceModifier: BigInt(stored.feeAssetPriceModifier),
+      inboxMsgTotal: BigInt(stored.inboxMsgTotal),
     };
   }
 
@@ -1361,7 +1363,7 @@ export class BlockStore {
    * Adds a proposed checkpoint to the pending queue.
    * Accepts proposed.checkpointNumber === latestTip + 1, where latestTip is the highest of
    * confirmed and the highest pending checkpoint number.
-   * Computes archive and checkpointOutHash from the stored blocks.
+   * Computes archive, checkpointOutHash and the consumed Inbox message total from the stored blocks.
    */
   async addProposedCheckpoint(proposed: ProposedCheckpointInput) {
     return await this.db.transactionAsync(async () => {
@@ -1387,8 +1389,12 @@ export class BlockStore {
       }
       this.validateCheckpointBlocks(blocks, previousBlock);
 
-      const archive = blocks[blocks.length - 1].archive;
+      const lastBlock = blocks[blocks.length - 1];
+      const archive = lastBlock.archive;
       const checkpointOutHash = Checkpoint.getCheckpointOutHash(blocks);
+      // The last block's L1-to-L2 leaf count is the checkpoint's cumulative consumed Inbox total under compact
+      // indexing, which is what `propose` records on L1 for it (AZIP-22 Fast Inbox).
+      const inboxMsgTotal = BigInt(lastBlock.header.state.l1ToL2MessageTree.nextAvailableLeafIndex);
 
       await this.#proposedCheckpoints.set(proposed.checkpointNumber, {
         header: proposed.header.toBuffer(),
@@ -1399,6 +1405,7 @@ export class BlockStore {
         blockCount: proposed.blockCount,
         totalManaUsed: proposed.totalManaUsed.toString(),
         feeAssetPriceModifier: proposed.feeAssetPriceModifier.toString(),
+        inboxMsgTotal: inboxMsgTotal.toString(),
       });
     });
   }

yarn-project/aztec-node/src/aztec-node/node_public_calls_simulator.test.ts

@@ -438,6 +438,7 @@ function makeProposedCheckpointData(args: {
     feeAssetPriceModifier: 7n,
     archive: new AppendOnlyTreeSnapshot(args.archiveRoot ?? Fr.ZERO, 0),
     checkpointOutHash: Fr.fromString('0xfeed'),
+    inboxMsgTotal: 0n,
   };
 }
 

yarn-project/aztec-node/src/aztec-node/server.test.ts

@@ -1395,6 +1395,7 @@ describe('aztec node', () => {
         blockCount: 1,
         totalManaUsed: 0n,
         feeAssetPriceModifier: 0n,
+        inboxMsgTotal: 0n,
       };
     }
 

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

@@ -451,6 +451,7 @@ describe('CheckpointProposalJob', () => {
           blockCount: 1,
           totalManaUsed: 5000n,
           feeAssetPriceModifier: 100n,
+          inboxMsgTotal: 0n,
         },
       });
 
@@ -650,6 +651,7 @@ describe('CheckpointProposalJob', () => {
         blockCount: 1,
         totalManaUsed: 5000n,
         feeAssetPriceModifier: 100n,
+        inboxMsgTotal: 0n,
       };
 
       job = createCheckpointProposalJob({
@@ -697,6 +699,7 @@ describe('CheckpointProposalJob', () => {
         blockCount: 1,
         totalManaUsed: 5000n,
         feeAssetPriceModifier: 100n,
+        inboxMsgTotal: 0n,
       };
 
       job = createCheckpointProposalJob({ targetSlot, targetEpoch, proposedCheckpointData });
@@ -848,6 +851,7 @@ describe('CheckpointProposalJob', () => {
       blockCount: 1,
       totalManaUsed: 5000n,
       feeAssetPriceModifier: 100n,
+      inboxMsgTotal: 0n,
     };
 
     let mismatchEvents: { slot: SlotNumber; checkpointNumber: CheckpointNumber; reason: string }[];

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

@@ -1575,6 +1575,7 @@ describe('sequencer', () => {
         blockCount: 1,
         totalManaUsed: 0n,
         feeAssetPriceModifier: 0n,
+        inboxMsgTotal: 0n,
       });
 
       await sequencer.work();
@@ -1700,6 +1701,7 @@ describe('sequencer', () => {
         blockCount: 1,
         totalManaUsed: 0n,
         feeAssetPriceModifier: 0n,
+        inboxMsgTotal: 0n,
       });
 
       await sequencer.work();
@@ -1829,6 +1831,7 @@ describe('sequencer', () => {
           blockCount: 1,
           totalManaUsed: 0n,
           feeAssetPriceModifier: 0n,
+          inboxMsgTotal: 0n,
         },
       });
 

yarn-project/stdlib/src/checkpoint/checkpoint_data.ts

@@ -42,6 +42,18 @@ export type ProposedOnlyCheckpointData = {
   feeAssetPriceModifier: bigint;
 };
 
+/** Inbox consumption record of a proposed checkpoint, mirroring what `propose` writes for it on L1. */
+export type ProposedInboxConsumption = {
+  /**
+   * Cumulative Inbox message count consumed as of this checkpoint: its last block's L1-to-L2 message tree leaf count
+   * under compact indexing (AZIP-22 Fast Inbox). L1 records this per checkpoint and reads it back as the parent total
+   * when validating the next checkpoint's consumption, so a simulation against a not-yet-mined parent must override
+   * the parent's cell with it — otherwise the parent reads as having consumed nothing and the child's consumption
+   * looks larger than it is.
+   */
+  inboxMsgTotal: bigint;
+};
+
 /** Lightweight checkpoint metadata without full block data. */
 export type CheckpointData = CommonCheckpointData & StorageEnrichedCheckpointData & L1EnrichedCheckpointData;
 
@@ -51,7 +63,7 @@ export type ProposedCheckpointInput = CommonCheckpointData & ProposedOnlyCheckpo
 
 /** Full data for a proposed checkpoint (proposed but not yet L1-confirmed).
  *  Includes fee-relevant fields used during pipelining to compute the fee header override. */
-export type ProposedCheckpointData = ProposedCheckpointInput & StorageEnrichedCheckpointData;
+export type ProposedCheckpointData = ProposedCheckpointInput & StorageEnrichedCheckpointData & ProposedInboxConsumption;
 
 export const ProposedCheckpointDataSchema = z.object({
   checkpointNumber: CheckpointNumberSchema,
@@ -62,6 +74,7 @@ export const ProposedCheckpointDataSchema = z.object({
   blockCount: z.number(),
   totalManaUsed: schemas.BigInt,
   feeAssetPriceModifier: schemas.BigInt,
+  inboxMsgTotal: schemas.BigInt,
 });
 
 export const CheckpointDataSchema = z

yarn-project/stdlib/src/checkpoint/previous_checkpoint_out_hashes.test.ts

@@ -37,6 +37,7 @@ function proposedParent(number: number, slot: number, outHash: Fr): ProposedChec
     blockCount: 1,
     totalManaUsed: 0n,
     feeAssetPriceModifier: 0n,
+    inboxMsgTotal: 0n,
   };
 }
 

yarn-project/stdlib/src/checkpoint/simulation_overrides.test.ts

@@ -31,6 +31,7 @@ describe('computePipelinedParentFeeHeader', () => {
     blockCount: 1,
     totalManaUsed: 5000n,
     feeAssetPriceModifier: 100n,
+    inboxMsgTotal: 0n,
   };
 
   const grandparentFeeHeader: FeeHeader = {
@@ -157,6 +158,7 @@ describe('buildCheckpointSimulationOverridesPlan', () => {
       blockCount: 1,
       totalManaUsed: 5000n,
       feeAssetPriceModifier: 100n,
+      inboxMsgTotal: 1500n,
     };
   }
 
@@ -194,6 +196,8 @@ describe('buildCheckpointSimulationOverridesPlan', () => {
     expect(plan?.pendingCheckpointState?.outHash).toEqual(proposedData.checkpointOutHash);
     expect(plan?.pendingCheckpointState?.payloadDigest).toBeDefined();
     expect(plan?.pendingCheckpointState?.feeHeader).toBeDefined();
+    // Without this the parent reads as having consumed no Inbox messages, inflating the child's consumed count.
+    expect(plan?.pendingCheckpointState?.inboxMsgTotal).toEqual(proposedData.inboxMsgTotal);
   });
 
   it('throws when the pipelined parent does not match the expected parent checkpoint', async () => {

yarn-project/stdlib/src/checkpoint/simulation_overrides.ts

@@ -73,21 +73,25 @@ export async function buildCheckpointSimulationOverridesPlan(
   builder.withChainTips({ pending: overridenChainTip, proven: overridenChainTip });
 
   if (input.proposedCheckpointData) {
-    const { header, archive, checkpointOutHash, feeAssetPriceModifier } = input.proposedCheckpointData;
+    const { header, archive, checkpointOutHash, feeAssetPriceModifier, inboxMsgTotal } = input.proposedCheckpointData;
     builder.withPendingArchive(archive.root);
     // Override every locally-derivable `tempCheckpointLogs[parent]` field that L1 will eventually
-    // write. `slotNumber` is load-bearing for `STFLib.canPruneAtTime`: without it the cell reads
+    // write. `slotNumber` is required by `STFLib.canPruneAtTime`: without it the cell reads
     // slotNumber 0, the contract treats the pending tip as belonging to an expired epoch, and
     // `getEffectivePendingCheckpointNumber` silently collapses pending back to proven — producing
-    // a spurious `Rollup__InvalidArchive` against the on-chain genesis archive. The other fields
-    // (headerHash, outHash, payloadDigest) are not strictly load-bearing for `canProposeAt` /
-    // `validateBlockHeader`, but mirroring the full cell keeps the simulation byte-faithful with
-    // what the actual `propose()` send will observe, which is a defense against future reads
-    // taking dependencies on them.
+    // a spurious `Rollup__InvalidArchive` against the on-chain genesis archive. `inboxMsgTotal` is
+    // read by `ProposeLib.validateInboxConsumption` as the parent's consumed total: left at zero it
+    // makes our consumption look like the Inbox's entire history and trips
+    // `Rollup__TooManyInboxMessagesConsumed`. The remaining fields (headerHash, outHash,
+    // payloadDigest) are not read by `canProposeAt` / `validateBlockHeader`, but mirroring the full
+    // cell keeps the simulation byte-faithful with what the actual `propose()` send will observe,
+    // which is a defense against future reads taking dependencies on them. The parent's
+    // `inboxConsumedBucket` shares the word and stays zero: no contract path reads it back.
     builder.withPendingTempCheckpointLogFields({
       headerHash: header.hash(),
       outHash: checkpointOutHash,
       slotNumber: header.slotNumber,
+      inboxMsgTotal,
       payloadDigest: computeCheckpointPayloadDigest({
         header,
         archiveRoot: archive.root,