op-node: fix parent-beacon-block-root comparison check [Ecotone] (#9071)

* op-node: fix parent-beacon-block-root comparison check

* op-node: nit in op-node/rollup/derive/engine_consolidate.go
Co-authored-by: Sebastian Stammler <seb@oplabs.co>

* op-node: two-side nil parent beacon block root test case

---------
Co-authored-by: Sebastian Stammler <seb@oplabs.co>

op-node/rollup/derive/engine_consolidate.go

@@ -47,8 +47,23 @@ func AttributesMatchBlock(rollupCfg *rollup.Config, attrs *eth.PayloadAttributes
 	if withdrawalErr := checkWithdrawalsMatch(attrs.Withdrawals, block.Withdrawals); withdrawalErr != nil {
 		return withdrawalErr
 	}
-	if envelope.ParentBeaconBlockRoot != attrs.ParentBeaconBlockRoot {
-		return fmt.Errorf("parent beacon block root does not match. expected %v. got: %v", attrs.ParentBeaconBlockRoot, envelope.ParentBeaconBlockRoot)
+	if err := checkParentBeaconBlockRootMatch(attrs.ParentBeaconBlockRoot, envelope.ParentBeaconBlockRoot); err != nil {
+		return err
+	}
+	return nil
+}
+
+func checkParentBeaconBlockRootMatch(attrRoot, blockRoot *common.Hash) error {
+	if blockRoot == nil {
+		if attrRoot != nil {
+			return fmt.Errorf("expected non-nil parent beacon block root %s but got nil", *attrRoot)
+		}
+	} else {
+		if attrRoot == nil {
+			return fmt.Errorf("expected nil parent beacon block root but got non-nil %s", *blockRoot)
+		} else if *blockRoot != *attrRoot {
+			return fmt.Errorf("parent beacon block root does not match. expected %s. got: %s", *attrRoot, *blockRoot)
+		}
 	}
 	return nil
 }

op-node/rollup/derive/engine_consolidate_test.go

@@ -71,6 +71,33 @@ func ecotoneNoParentBeaconBlockRoot() args {
 	return args
 }
 
+func ecotoneUnexpectedParentBeaconBlockRoot() args {
+	args := ecotoneArgs()
+	args.attrs.ParentBeaconBlockRoot = nil
+	return args
+}
+
+func ecotoneMismatchParentBeaconBlockRoot() args {
+	args := ecotoneArgs()
+	h := common.HexToHash("0xabc")
+	args.attrs.ParentBeaconBlockRoot = &h
+	return args
+}
+
+func ecotoneMismatchParentBeaconBlockRootPtr() args {
+	args := ecotoneArgs()
+	cpy := *args.attrs.ParentBeaconBlockRoot
+	args.attrs.ParentBeaconBlockRoot = &cpy
+	return args
+}
+
+func ecotoneNilParentBeaconBlockRoots() args {
+	args := ecotoneArgs()
+	args.attrs.ParentBeaconBlockRoot = nil
+	args.envelope.ParentBeaconBlockRoot = nil
+	return args
+}
+
 func mismatchedParentHashArgs() args {
 	args := ecotoneArgs()
 	args.parentHash = common.HexToHash("0xabc")
@@ -130,6 +157,22 @@ func TestAttributesMatch(t *testing.T) {
 			shouldMatch: false,
 			args:        ecotoneNoParentBeaconBlockRoot(),
 		},
+		{
+			shouldMatch: false,
+			args:        ecotoneUnexpectedParentBeaconBlockRoot(),
+		},
+		{
+			shouldMatch: false,
+			args:        ecotoneMismatchParentBeaconBlockRoot(),
+		},
+		{
+			shouldMatch: true,
+			args:        ecotoneMismatchParentBeaconBlockRootPtr(),
+		},
+		{
+			shouldMatch: true,
+			args:        ecotoneNilParentBeaconBlockRoots(),
+		},
 		{
 			shouldMatch: false,
 			args:        createMistmatchedPrevRandao(),