Do not attach headers if Span is NoOp

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+### Fixes
+
+- Do not attach headers if Span is NoOp ([#1143](https://github.com/getsentry/sentry-dart/pull/1143))
+
 ## 6.16.0
 
 ### Features

dart/lib/src/http_client/tracing_client.dart

@@ -2,6 +2,7 @@ import 'package:http/http.dart';
 import '../hub.dart';
 import '../hub_adapter.dart';
 import '../protocol.dart';
+import '../tracing.dart';
 import '../utils/tracing_utils.dart';
 
 /// A [http](https://pub.dev/packages/http)-package compatible HTTP client
@@ -19,11 +20,16 @@ class TracingClient extends BaseClient {
   Future<StreamedResponse> send(BaseRequest request) async {
     // see https://develop.sentry.dev/sdk/performance/#header-sentry-trace
     final currentSpan = _hub.getSpan();
-    final span = currentSpan?.startChild(
+    var span = currentSpan?.startChild(
       'http.client',
       description: '${request.method} ${request.url}',
     );
 
+    // if the span is NoOp, we dont want to attach headers
+    if (span is NoOpSentrySpan) {
+      span = null;
+    }
+
     StreamedResponse? response;
     try {
       if (span != null) {

dart/test/http_client/tracing_client_test.dart

@@ -135,6 +135,20 @@ void main() {
       expect(response.request!.headers[sentryTrace.name], sentryTrace.value);
     });
 
+    test('captured span do not add headers if NoOp', () async {
+      final sut = fixture.getSut(
+        client: fixture.getClient(statusCode: 200, reason: 'OK'),
+      );
+
+      await fixture._hub
+          .configureScope((scope) => scope.span = NoOpSentrySpan());
+
+      final response = await sut.get(requestUri);
+
+      expect(response.request!.headers['baggage'], null);
+      expect(response.request!.headers['sentry-trace'], null);
+    });
+
     test('captured span do not add headers if origins not set', () async {
       final sut = fixture.getSut(
         client: fixture.getClient(

dio/lib/src/tracing_client_adapter.dart

@@ -25,11 +25,16 @@ class TracingClientAdapter extends HttpClientAdapter {
   ) async {
     // see https://develop.sentry.dev/sdk/performance/#header-sentry-trace
     final currentSpan = _hub.getSpan();
-    final span = currentSpan?.startChild(
+    var span = currentSpan?.startChild(
       'http.client',
       description: '${options.method} ${options.uri}',
     );
 
+    // if the span is NoOp, we dont want to attach headers
+    if (span is NoOpSentrySpan) {
+      span = null;
+    }
+
     ResponseBody? response;
     try {
       if (span != null) {

dio/test/tracing_client_adapter_test.dart

@@ -121,6 +121,19 @@ void main() {
       );
     });
 
+    test('captured span do not add headers if NoOp', () async {
+      final sut = fixture.getSut(
+        client: fixture.getClient(statusCode: 200, reason: 'OK'),
+      );
+      await fixture._hub
+          .configureScope((scope) => scope.span = NoOpSentrySpan());
+
+      final response = await sut.get<dynamic>(requestOptions);
+
+      expect(response.headers['baggage'], null);
+      expect(response.headers['sentry-trace'], null);
+    });
+
     test('do not throw if no span bound to the scope', () async {
       final sut = fixture.getSut(
         client: fixture.getClient(statusCode: 200, reason: 'OK'),