fix: align BeaconBlockBody and BlindedBeaconBlockBody (ChainSafe#6782)

* fix: align BeaconBlockBody and BlindedBeaconBlockBody

* Remove type hacks in test

---------

Co-authored-by: Nico Flaig <nflaig@protonmail.com>

packages/types/src/electra/sszTypes.ts

@@ -223,6 +223,7 @@ export const BlindedBeaconBlockBody = new ContainerType(
     executionPayloadHeader: ExecutionPayloadHeader, // Modified in ELECTRA
     blsToExecutionChanges: capellaSsz.BeaconBlockBody.fields.blsToExecutionChanges,
     blobKzgCommitments: denebSsz.BeaconBlockBody.fields.blobKzgCommitments,
+    consolidations: new ListCompositeType(SignedConsolidation, MAX_CONSOLIDATIONS), // [New in Electra]
   },
   {typeName: "BlindedBeaconBlockBody", jsonCase: "eth2", cachePermanentRootStruct: true}
 );

packages/types/test/unit/blinded.test.ts

@@ -0,0 +1,35 @@
+import {describe, it, expect} from "vitest";
+import {ForkName, isForkExecution} from "@lodestar/params";
+import {ssz} from "../../src/index.js";
+
+describe("blinded data structures", function () {
+  it("should have the same number of fields as non-blinded", () => {
+    const blindedTypes = [
+      {a: "BlindedBeaconBlockBody" as const, b: "BeaconBlockBody" as const},
+      {a: "ExecutionPayloadHeader" as const, b: "ExecutionPayload" as const},
+    ];
+
+    for (const {a, b} of blindedTypes) {
+      for (const fork of Object.keys(ssz.allForks) as ForkName[]) {
+        if (!isForkExecution(fork)) {
+          continue;
+        }
+
+        const blindedType = ssz[fork][a];
+        if (blindedType === undefined) {
+          expect.fail(`fork: ${fork}, type ${a} is undefined`);
+        }
+
+        const type = ssz[fork][b];
+        if (type === undefined) {
+          expect.fail(`fork: ${fork}, type ${b} is undefined`);
+        }
+
+        expect(Object.keys(blindedType.fields).length).toBeWithMessage(
+          Object.keys(type.fields).length,
+          `fork: ${fork}, types ${a} and ${b} have different number of fields`
+        );
+      }
+    }
+  });
+});