fix admin server responses, fix zero values handling

Author: maxdml

dbos/admin_server.go

@@ -152,20 +152,23 @@ func toListWorkflowResponse(ws WorkflowStatus) (map[string]any, error) {
 		result["StartedAt"] = nil
 	}
 
-	if ws.Input != nil && ws.Input != "" {
-		bytes, err := json.Marshal(ws.Input)
-		if err != nil {
-			return nil, fmt.Errorf("failed to marshal input: %w", err)
+	if ws.Input != nil {
+		// If there is a value, it should be a JSON string
+		jsonInput, ok := ws.Input.(string)
+		if ok {
+			result["Input"] = jsonInput
+		} else {
+			result["Input"] = ""
 		}
-		result["Input"] = string(bytes)
 	}
 
-	if ws.Output != nil && ws.Output != "" {
-		bytes, err := json.Marshal(ws.Output)
-		if err != nil {
-			return nil, fmt.Errorf("failed to marshal output: %w", err)
+	if ws.Output != nil {
+		jsonOutput, ok := ws.Output.(string)
+		if ok {
+			result["Output"] = jsonOutput
+		} else {
+			result["Output"] = ""
 		}
-		result["Output"] = string(bytes)
 	}
 
 	if ws.Error != nil {
@@ -439,15 +442,16 @@ func newAdminServer(ctx *dbosContext, port int) *adminServer {
 				"child_workflow_id": step.ChildWorkflowID,
 			}
 
-			// Marshal Output as JSON string if present
-			if step.Output != nil && step.Output != "" {
-				bytes, err := json.Marshal(step.Output)
-				if err != nil {
-					ctx.logger.Error("Failed to marshal step output", "error", err)
-					http.Error(w, fmt.Sprintf("Failed to format step output: %v", err), http.StatusInternalServerError)
-					return
+			if step.Output != nil {
+				// If there is a value, it should be a JSON string
+				jsonOutput, ok := step.Output.(string)
+				if ok {
+					formattedStep["output"] = jsonOutput
+				} else {
+					formattedStep["output"] = ""
 				}
-				formattedStep["output"] = string(bytes)
+			} else {
+				formattedStep["output"] = ""
 			}
 
 			// Marshal Error as JSON string if present

dbos/admin_server_test.go

@@ -874,22 +874,9 @@ func TestAdminServer(t *testing.T) {
 				assert.Contains(t, unmarshaledError, "deliberate error for testing", "Error message should be preserved")
 
 			case "emptyStep":
-				// Empty string might be returned as nil or as an empty JSON string
+				// Empty string is returned as an empty JSON string
 				output := step["output"]
-				if output == nil {
-					// Empty string was not included in response (which is fine)
-					t.Logf("Empty step output was nil (not included)")
-				} else {
-					// If it was included, it should be marshaled as JSON string `""`
-					outputStr, ok := output.(string)
-					require.True(t, ok, "If present, empty step output should be a JSON string")
-
-					var unmarshaledOutput string
-					err = json.Unmarshal([]byte(outputStr), &unmarshaledOutput)
-					require.NoError(t, err, "Failed to unmarshal empty step output")
-					assert.Equal(t, "", unmarshaledOutput, "Empty step output should be empty string")
-				}
-
+				require.Equal(t, "", output, "Empty step output should be an empty string")
 				assert.Nil(t, step["error"], "Empty step should have no error")
 			}
 		}

dbos/queues_test.go

@@ -541,9 +541,13 @@ func TestQueueRecovery(t *testing.T) {
 			// Root workflow case
 			resultAny, err := h.GetResult()
 			require.NoError(t, err, "failed to get result from recovered root workflow handle")
-			// Decode the result from any (which may be []interface{} after JSON decode) to []int
+			// re-encode and decode the result from []interface{} to []int
+			encodedResult, ok := resultAny.([]any)
+			require.True(t, ok, "expected result to be a []any")
+			jsonBytes, err := json.Marshal(encodedResult)
+			require.NoError(t, err, "failed to marshal result to JSON")
 			var castedResult []int
-			err = json.Unmarshal([]byte(resultAny.(string)), &castedResult)
+			err = json.Unmarshal(jsonBytes, &castedResult)
 			require.NoError(t, err, "failed to decode result to []int")
 			expectedResult := []int{0, 1, 2, 3, 4}
 			assert.Equal(t, expectedResult, castedResult, "expected result %v, got %v", expectedResult, castedResult)

dbos/serialization.go

@@ -19,7 +19,7 @@ func newJSONSerializer[T any]() serializer[T] {
 }
 
 func (j *jsonSerializer[T]) Encode(data T) (string, error) {
-	if isNilValue(data) {
+	if isNilOrZeroValue(data) {
 		// For nil values, encode an empty byte slice directly to base64
 		return base64.StdEncoding.EncodeToString([]byte{}), nil
 	}
@@ -57,8 +57,8 @@ func (j *jsonSerializer[T]) Decode(data *string) (T, error) {
 	return result, nil
 }
 
-// isNilValue checks if a value is nil (for pointer types, slice, map, etc.)
-func isNilValue(v any) bool {
+// isNilOrZeroValue checks if a value is nil (for pointer types, slice, map, etc.) or a zero value.
+func isNilOrZeroValue(v any) bool {
 	val := reflect.ValueOf(v)
 	if !val.IsValid() {
 		return true
@@ -67,7 +67,8 @@ func isNilValue(v any) bool {
 	case reflect.Pointer, reflect.Slice, reflect.Map, reflect.Chan, reflect.Func:
 		return val.IsNil()
 	}
-	return false
+	// For other types, check if it's the zero value
+	return val.IsZero()
 }
 
 // IsNestedPointer checks if a type is a nested pointer (e.g., **int, ***int).

dbos/serialization_test.go

@@ -26,7 +26,7 @@ func testAllSerializationPaths[T any](
 ) {
 	t.Helper()
 
-	isNilExpected := isNilValue(input)
+	isNilExpected := isNilOrZeroValue(input)
 
 	// Setup events for recovery
 	startEvent := NewEvent()

dbos/workflow.go

@@ -2070,6 +2070,9 @@ func (c *dbosContext) ListWorkflows(_ DBOSContext, opts ...ListWorkflowsOption)
 				if !ok {
 					return nil, fmt.Errorf("workflow input must be encoded string, got %T", workflows[i].Input)
 				}
+				if encodedInput == nil {
+					continue
+				}
 				decodedBytes, err := base64.StdEncoding.DecodeString(*encodedInput)
 				if err != nil {
 					return nil, fmt.Errorf("failed to decode base64 workflow input for %s: %w", workflows[i].ID, err)
@@ -2079,7 +2082,10 @@ func (c *dbosContext) ListWorkflows(_ DBOSContext, opts ...ListWorkflowsOption)
 			if params.loadOutput && workflows[i].Output != nil {
 				encodedOutput, ok := workflows[i].Output.(*string)
 				if !ok {
-					return nil, fmt.Errorf("workflow output must be encoded string, got %T", workflows[i].Output)
+					return nil, fmt.Errorf("workflow output must be encoded *string, got %T", workflows[i].Output)
+				}
+				if encodedOutput == nil {
+					continue
 				}
 				decodedBytes, err := base64.StdEncoding.DecodeString(*encodedOutput)
 				if err != nil {