fix(execution): clear omitted payload envelope optionals (#3439)

Signed-off-by: elonfliter <elonfliter@outlook.com>
Co-authored-by: Marko <marko@baricevic.me>

Author: elonfliter

execution/evm/engine_payload.go

@@ -85,15 +85,14 @@ func (e *EnginePayloadEnvelope) UnmarshalJSON(input []byte) error {
 	e.BlockValue = (*big.Int)(dec.BlockValue)
 	e.BlobsBundle = dec.BlobsBundle
 
+	e.Requests = nil
 	if dec.Requests != nil {
 		e.Requests = make([][]byte, len(dec.Requests))
 		for i, request := range dec.Requests {
 			e.Requests[i] = request
 		}
 	}
-	if dec.Override != nil {
-		e.Override = *dec.Override
-	}
+	e.Override = dec.Override != nil && *dec.Override
 	e.Witness = dec.Witness
 	return nil
 }

execution/evm/engine_rpc_client_test.go

@@ -573,6 +573,29 @@ func TestEnginePayloadEnvelope_MarshalJSON_UsesWireFieldNames(t *testing.T) {
 	require.JSONEq(t, string(envelope.RawExecutionPayload), string(decoded.RawExecutionPayload))
 }
 
+func TestEnginePayloadEnvelope_UnmarshalClearsOmittedFields(t *testing.T) {
+	withOptionals := strings.ReplaceAll(minimalPayloadEnvelopeJSON,
+		`"executionRequests": []`, `"executionRequests": ["0x01"]`)
+	withOptionals = strings.ReplaceAll(withOptionals,
+		`"shouldOverrideBuilder": false`, `"shouldOverrideBuilder": true`)
+
+	var envelope EnginePayloadEnvelope
+	require.NoError(t, json.Unmarshal([]byte(withOptionals), &envelope))
+	require.NotEmpty(t, envelope.Requests)
+	require.True(t, envelope.Override)
+
+	var withoutOptionals map[string]json.RawMessage
+	require.NoError(t, json.Unmarshal([]byte(minimalPayloadEnvelopeJSON), &withoutOptionals))
+	delete(withoutOptionals, "executionRequests")
+	delete(withoutOptionals, "shouldOverrideBuilder")
+	encoded, err := json.Marshal(withoutOptionals)
+	require.NoError(t, err)
+
+	require.NoError(t, json.Unmarshal(encoded, &envelope))
+	require.Nil(t, envelope.Requests)
+	require.False(t, envelope.Override)
+}
+
 func TestIsUnsupportedForkErr(t *testing.T) {
 	tests := []struct {
 		name     string