feat: block gossip validation for parent payload (consensus-specs#4923)

packages/beacon-node/src/chain/errors/blockError.ts

@@ -70,6 +70,8 @@ export enum BlockErrorCode {
   TOO_MANY_KZG_COMMITMENTS = "BLOCK_ERROR_TOO_MANY_KZG_COMMITMENTS",
   /** Bid parent block root does not match block parent root */
   BID_PARENT_ROOT_MISMATCH = "BLOCK_ERROR_BID_PARENT_ROOT_MISMATCH",
+  /** Parent execution payload has not been seen */
+  PARENT_PAYLOAD_UNKNOWN = "BLOCK_ERROR_PARENT_PAYLOAD_UNKNOWN",
 }
 
 type ExecutionErrorStatus = Exclude<
@@ -114,7 +116,8 @@ export type BlockErrorType =
   | {code: BlockErrorCode.EXECUTION_ENGINE_ERROR; execStatus: ExecutionErrorStatus; errorMessage: string}
   | {code: BlockErrorCode.DATA_UNAVAILABLE}
   | {code: BlockErrorCode.TOO_MANY_KZG_COMMITMENTS; blobKzgCommitmentsLen: number; commitmentLimit: number}
-  | {code: BlockErrorCode.BID_PARENT_ROOT_MISMATCH; bidParentRoot: RootHex; blockParentRoot: RootHex};
+  | {code: BlockErrorCode.BID_PARENT_ROOT_MISMATCH; bidParentRoot: RootHex; blockParentRoot: RootHex}
+  | {code: BlockErrorCode.PARENT_PAYLOAD_UNKNOWN; parentBlockHash: RootHex};
 
 export class BlockGossipError extends GossipActionError<BlockErrorType> {}
 

packages/beacon-node/src/chain/validation/block.ts

@@ -153,6 +153,17 @@ export async function validateGossipBlock(
       });
     }
 
+    // [IGNORE] The block's parent execution payload (defined by bid.parent_block_hash) has been seen
+    // (via gossip or non-gossip sources) (a client MAY queue blocks for processing once the parent
+    // payload is retrieved).
+    const parentBlockHashHex = toRootHex(bid.parentBlockHash);
+    if (!chain.forkChoice.hasExecutionPayload(parentBlockHashHex)) {
+      throw new BlockGossipError(GossipAction.IGNORE, {
+        code: BlockErrorCode.PARENT_PAYLOAD_UNKNOWN,
+        parentBlockHash: parentBlockHashHex,
+      });
+    }
+
     // TODO GLOAS: [REJECT] The block's execution payload parent (defined by bid.parent_block_hash) passes all validation
     // This requires execution engine integration to verify the parent block hash
   }

packages/fork-choice/src/forkChoice/forkChoice.ts

@@ -1056,6 +1056,14 @@ export class ForkChoice implements IForkChoice {
     return this.protoArray.hasBlock(blockRoot);
   }
 
+  /**
+   * Check if an execution payload with the given block hash has been seen.
+   * Spec: gloas/p2p-interface.md — parent execution payload must have been seen
+   */
+  hasExecutionPayload(executionPayloadBlockHash: RootHex): boolean {
+    return this.protoArray.hasExecutionPayload(executionPayloadBlockHash);
+  }
+
   /**
    * Returns a MUTABLE `ProtoBlock` if the block is known **and** a descendant of the finalized root.
    */

packages/fork-choice/src/forkChoice/interface.ts

@@ -228,6 +228,11 @@ export interface IForkChoice {
    */
   hasBlockUnsafe(blockRoot: Root): boolean;
   hasBlockHexUnsafe(blockRoot: RootHex): boolean;
+  /**
+   * Check if an execution payload with the given block hash has been seen.
+   * For Gloas: checks if any block has a FULL variant with matching execution payload block hash.
+   */
+  hasExecutionPayload(executionPayloadBlockHash: RootHex): boolean;
   getSlotsPresent(windowStart: number): number;
   /**
    * Returns a `ProtoBlock` if the block is known **and** a descendant of the finalized root.

packages/fork-choice/src/protoArray/protoArray.ts

@@ -1671,6 +1671,36 @@ export class ProtoArray {
     return this.getDefaultNodeIndex(blockRoot) !== undefined;
   }
 
+  /**
+   * Check if an execution payload with the given block hash has been seen.
+   * Looks through all nodes with FULL variant status for a matching executionPayloadBlockHash.
+   * Used for Gloas gossip validation: parent execution payload must have been seen.
+   *
+   * TODO GLOAS: Add secondary index (Set<RootHex> by executionPayloadBlockHash) for O(1) lookups.
+   * Current O(n) linear scan is acceptable during development but should be optimized before mainnet.
+   */
+  hasExecutionPayload(executionPayloadBlockHash: RootHex): boolean {
+    for (const [, variantOrArr] of this.indices) {
+      if (!Array.isArray(variantOrArr)) {
+        // Pre-Gloas: check directly
+        const node = this.nodes[variantOrArr];
+        if (node?.executionPayloadBlockHash === executionPayloadBlockHash) {
+          return true;
+        }
+      } else {
+        // Gloas: check FULL variant if it exists
+        const fullIndex = variantOrArr[PayloadStatus.FULL];
+        if (fullIndex !== undefined) {
+          const node = this.nodes[fullIndex];
+          if (node?.executionPayloadBlockHash === executionPayloadBlockHash) {
+            return true;
+          }
+        }
+      }
+    }
+    return false;
+  }
+
   /**
    * Return ProtoNode for blockRoot with explicit payload status
    *