chore: Sanity check block number from archiver before returning it (#13631)

We have seen an archiver that stored blocks under the wrong block
number, which caused errors in other components. This adds a sanity
check before returning them.

Author: spalladino

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

@@ -130,8 +130,8 @@ export class BlockStore {
    * @returns The requested L2 blocks
    */
   async *getBlocks(start: number, limit: number): AsyncIterableIterator<PublishedL2Block> {
-    for await (const blockStorage of this.#blocks.valuesAsync(this.#computeBlockRange(start, limit))) {
-      const block = await this.getBlockFromBlockStorage(blockStorage);
+    for await (const [blockNumber, blockStorage] of this.#blocks.entriesAsync(this.#computeBlockRange(start, limit))) {
+      const block = await this.getBlockFromBlockStorage(blockNumber, blockStorage);
       if (block) {
         yield block;
       }
@@ -148,7 +148,7 @@ export class BlockStore {
     if (!blockStorage || !blockStorage.header) {
       return Promise.resolve(undefined);
     }
-    return this.getBlockFromBlockStorage(blockStorage);
+    return this.getBlockFromBlockStorage(blockNumber, blockStorage);
   }
 
   /**
@@ -158,12 +158,18 @@ export class BlockStore {
    * @returns The requested L2 block headers
    */
   async *getBlockHeaders(start: number, limit: number): AsyncIterableIterator<BlockHeader> {
-    for await (const blockStorage of this.#blocks.valuesAsync(this.#computeBlockRange(start, limit))) {
-      yield BlockHeader.fromBuffer(blockStorage.header);
+    for await (const [blockNumber, blockStorage] of this.#blocks.entriesAsync(this.#computeBlockRange(start, limit))) {
+      const header = BlockHeader.fromBuffer(blockStorage.header);
+      if (header.getBlockNumber() !== blockNumber) {
+        throw new Error(
+          `Block number mismatch when retrieving block header from archive (expected ${blockNumber} but got ${header.getBlockNumber()})`,
+        );
+      }
+      yield header;
     }
   }
 
-  private async getBlockFromBlockStorage(blockStorage: BlockStorage) {
+  private async getBlockFromBlockStorage(blockNumber: number, blockStorage: BlockStorage) {
     const header = BlockHeader.fromBuffer(blockStorage.header);
     const archive = AppendOnlyTreeSnapshot.fromBuffer(blockStorage.archive);
     const blockHash = (await header.hash()).toString();
@@ -174,6 +180,13 @@ export class BlockStore {
     }
     const body = Body.fromBuffer(blockBodyBuffer);
     const block = new L2Block(archive, header, body);
+    if (block.number !== blockNumber) {
+      throw new Error(
+        `Block number mismatch when retrieving block from archive (expected ${blockNumber} but got ${
+          block.number
+        } with hash ${await block.hash()})`,
+      );
+    }
     const signatures = blockStorage.signatures.map(Signature.fromBuffer);
     return { block, l1: blockStorage.l1, signatures };
   }

yarn-project/stdlib/src/block/l2_block.ts

@@ -106,7 +106,7 @@ export class L2Block {
   }
 
   get number(): number {
-    return Number(this.header.globalVariables.blockNumber.toBigInt());
+    return this.header.getBlockNumber();
   }
 
   /**

yarn-project/stdlib/src/tx/block_header.ts

@@ -64,6 +64,10 @@ export class BlockHeader {
     return this.globalVariables.slotNumber.toBigInt();
   }
 
+  getBlockNumber(): number {
+    return Number(this.globalVariables.blockNumber.toBigInt());
+  }
+
   getSize() {
     return (
       this.lastArchive.getSize() +