feat: check gas limit consistency with the target

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

@@ -9,6 +9,7 @@ export enum ExecutionPayloadBidErrorCode {
   BID_TOO_HIGH = "EXECUTION_PAYLOAD_BID_ERROR_BID_TOO_HIGH",
   TOO_MANY_KZG_COMMITMENTS = "EXECUTION_PAYLOAD_BID_ERROR_TOO_MANY_KZG_COMMITMENTS",
   UNKNOWN_BLOCK_ROOT = "EXECUTION_PAYLOAD_BID_ERROR_UNKNOWN_BLOCK_ROOT",
+  UNKNOWN_PARENT_BLOCK_HASH = "EXECUTION_PAYLOAD_BID_ERROR_UNKNOWN_PARENT_BLOCK_HASH",
   INVALID_SLOT = "EXECUTION_PAYLOAD_BID_ERROR_INVALID_SLOT",
   INVALID_SIGNATURE = "EXECUTION_PAYLOAD_BID_ERROR_INVALID_SIGNATURE",
   NO_MATCHING_PROPOSER_PREFERENCES = "EXECUTION_PAYLOAD_BID_ERROR_NO_MATCHING_PROPOSER_PREFERENCES",
@@ -38,6 +39,7 @@ export type ExecutionPayloadBidErrorType =
       commitmentLimit: number;
     }
   | {code: ExecutionPayloadBidErrorCode.UNKNOWN_BLOCK_ROOT; parentBlockRoot: RootHex}
+  | {code: ExecutionPayloadBidErrorCode.UNKNOWN_PARENT_BLOCK_HASH; parentBlockHash: RootHex}
   | {code: ExecutionPayloadBidErrorCode.INVALID_SLOT; builderIndex: BuilderIndex; slot: Slot}
   | {code: ExecutionPayloadBidErrorCode.INVALID_SIGNATURE; builderIndex: BuilderIndex; slot: Slot}
   | {
@@ -56,7 +58,8 @@ export type ExecutionPayloadBidErrorType =
       code: ExecutionPayloadBidErrorCode.PROPOSER_PREFERENCES_GAS_LIMIT_MISMATCH;
       builderIndex: BuilderIndex;
       bidGasLimit: number;
-      expectedGasLimit: number;
+      parentGasLimit: number;
+      targetGasLimit: number;
     };
 
 export class ExecutionPayloadBidError extends GossipActionError<ExecutionPayloadBidErrorType> {}

packages/beacon-node/src/chain/produceBlock/produceBlockBody.ts

@@ -21,6 +21,7 @@ import {
   type IBeaconStateViewGloas,
   computeEpochAtSlot,
   computeTimeAtSlot,
+  getExpectedGasLimit,
   isStatePostBellatrix,
   isStatePostCapella,
   isStatePostGloas,
@@ -53,13 +54,7 @@ import {
 import {Logger, byteArrayEquals, fromHex, sleep, toHex, toPubkeyHex, toRootHex} from "@lodestar/utils";
 import {ZERO_HASH_HEX} from "../../constants/index.js";
 import {numToQuantity} from "../../execution/engine/utils.js";
-import {
-  IExecutionBuilder,
-  IExecutionEngine,
-  PayloadAttributes,
-  PayloadId,
-  getExpectedGasLimit,
-} from "../../execution/index.js";
+import {IExecutionBuilder, IExecutionEngine, PayloadAttributes, PayloadId} from "../../execution/index.js";
 import {getShufflingDependentRoot} from "../../util/dependentRoot.js";
 import {fromGraffitiBytes} from "../../util/graffiti.js";
 import {kzg} from "../../util/kzg.js";

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

@@ -4,6 +4,7 @@ import {
   createSingleSignatureSetFromComponents,
   getExecutionPayloadBidSigningRoot,
   isActiveBuilder,
+  isGasLimitTargetCompatible,
   isStatePostGloas,
 } from "@lodestar/state-transition";
 import {gloas} from "@lodestar/types";
@@ -128,14 +129,32 @@ async function validateExecutionPayloadBid(
     });
   }
 
-  // [REJECT] `bid.gas_limit == proposer_preferences.target_gas_limit`.
+  // [IGNORE] `bid.parent_block_hash` is the block hash of a known execution payload in fork
+  // choice. Partial implementation: we can only resolve the head's last committed bid because
+  // fork choice doesn't yet index per-payload metadata by EL block hash. Bids whose parent
+  // payload sits behind that (EMPTY-parent chains, sibling forks) get IGNORED and will
+  // re-enter the validator as the head catches up.
+  // TODO GLOAS: drop this guard once fork choice tracks executed-payload gas_limit by hash.
+  if (!byteArrayEquals(bid.parentBlockHash, state.latestExecutionPayloadBid.blockHash)) {
+    throw new ExecutionPayloadBidError(GossipAction.IGNORE, {
+      code: ExecutionPayloadBidErrorCode.UNKNOWN_PARENT_BLOCK_HASH,
+      parentBlockHash: parentBlockHashHex,
+    });
+  }
+
+  // [REJECT] `is_gas_limit_target_compatible(parent_gas_limit, bid.gas_limit, target_gas_limit)`,
+  // where `parent_gas_limit` is the `gas_limit` of the parent execution payload and
+  // `target_gas_limit` is `proposer_preferences.target_gas_limit`.
   const bidGasLimit = Number(bid.gasLimit);
-  if (bidGasLimit !== proposerPreferences.message.targetGasLimit) {
+  const parentGasLimit = Number(state.latestExecutionPayloadBid.gasLimit);
+  const targetGasLimit = proposerPreferences.message.targetGasLimit;
+  if (!isGasLimitTargetCompatible(parentGasLimit, bidGasLimit, targetGasLimit)) {
     throw new ExecutionPayloadBidError(GossipAction.REJECT, {
       code: ExecutionPayloadBidErrorCode.PROPOSER_PREFERENCES_GAS_LIMIT_MISMATCH,
       builderIndex: bid.builderIndex,
       bidGasLimit,
-      expectedGasLimit: proposerPreferences.message.targetGasLimit,
+      parentGasLimit,
+      targetGasLimit,
     });
   }
 
@@ -183,10 +202,6 @@ async function validateExecutionPayloadBid(
     });
   }
 
-  // [IGNORE] `bid.parent_block_hash` is the block hash of a known execution
-  // payload in fork choice.
-  // TODO GLOAS: implement this
-
   // [REJECT] `signed_execution_payload_bid.signature` is valid with respect to the `bid.builder_index`.
   const signatureSet = createSingleSignatureSetFromComponents(
     PublicKey.fromBytes(builder.pubkey),

packages/beacon-node/src/execution/builder/index.ts

@@ -1,11 +1,8 @@
 import {ChainForkConfig} from "@lodestar/config";
 import {Logger} from "@lodestar/logger";
 import {Metrics} from "../../metrics/metrics.js";
-import {IExecutionBuilder} from "./interface.js";
-
-export {getExpectedGasLimit} from "./utils.js";
-
 import {ExecutionBuilderHttp, ExecutionBuilderHttpOpts, defaultExecutionBuilderHttpOpts} from "./http.js";
+import {IExecutionBuilder} from "./interface.js";
 
 export {ExecutionBuilderHttp, defaultExecutionBuilderHttpOpts};
 

packages/state-transition/src/util/gloas.ts

@@ -73,6 +73,34 @@ export function isActiveBuilder(builder: gloas.Builder, finalizedEpoch: Epoch):
   return builder.depositEpoch < finalizedEpoch && builder.withdrawableEpoch === FAR_FUTURE_EPOCH;
 }
 
+/**
+ * Compute the gas limit that satisfies the EIP-1559 adjustment rule from `parentGasLimit`,
+ * clamping `targetGasLimit` into the allowed window of `±max(parentGasLimit / 1024, 1) - 1`.
+ *
+ * From https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1559.md
+ */
+export function getExpectedGasLimit(parentGasLimit: number, targetGasLimit: number): number {
+  const maxGasLimitDifference = Math.max(Math.floor(parentGasLimit / 1024), 1) - 1;
+
+  if (targetGasLimit > parentGasLimit) {
+    const gasDiff = targetGasLimit - parentGasLimit;
+    return parentGasLimit + Math.min(gasDiff, maxGasLimitDifference);
+  }
+
+  const gasDiff = parentGasLimit - targetGasLimit;
+  return parentGasLimit - Math.min(gasDiff, maxGasLimitDifference);
+}
+
+/**
+ * Check if `gasLimit` is compatible with `targetGasLimit` under the EIP-1559 transition rule
+ * from `parentGasLimit`. The bid must hit `targetGasLimit` when the target is within one
+ * adjustment step of the parent, otherwise it must hit the clamped boundary.
+ * Spec: https://github.com/ethereum/consensus-specs/blob/v1.7.0-alpha.8/specs/gloas/builder.md#new-is_gas_limit_target_compatible
+ */
+export function isGasLimitTargetCompatible(parentGasLimit: number, gasLimit: number, targetGasLimit: number): boolean {
+  return gasLimit === getExpectedGasLimit(parentGasLimit, targetGasLimit);
+}
+
 /**
  * Get the total pending balance to withdraw for a builder (from withdrawals + payments).
  * Spec: https://github.com/ethereum/consensus-specs/blob/v1.7.0-alpha.1/specs/gloas/beacon-chain.md#new-get_pending_balance_to_withdraw_for_builder

packages/beacon-node/test/unit/execution/builder/utils.test.ts → packages/state-transition/test/unit/util/gloas.test.ts

@@ -1,7 +1,7 @@
 import {describe, expect, it} from "vitest";
-import {getExpectedGasLimit} from "../../../../src/execution/builder/utils.js";
+import {getExpectedGasLimit} from "../../../src/util/gloas.js";
 
-describe("execution / builder / utils", () => {
+describe("util / gloas", () => {
   describe("getExpectedGasLimit", () => {
     const testCases: {
       name: string;

specrefs/functions.yml

@@ -6645,7 +6645,9 @@
     </spec>
 
 - name: is_gas_limit_target_compatible#gloas
-  sources: []
+  sources:
+    - file: packages/state-transition/src/util/gloas.ts
+      search: export function isGasLimitTargetCompatible(
   spec: |
     <spec fn="is_gas_limit_target_compatible" fork="gloas" hash="3fa22023">
     def is_gas_limit_target_compatible(