remove breadcrumbs from transaction in sentry client

dart/lib/src/sentry_client.dart

@@ -108,18 +108,7 @@ class SentryClient {
       return _sentryId;
     }
 
-    if (_options.platformChecker.platform.isAndroid &&
-        _options.enableScopeSync) {
-      /*
-      We do this to avoid duplicate breadcrumbs on Android as sentry-android applies the breadcrumbs
-      from the native scope onto every envelope sent through it. This scope will contain the breadcrumbs
-      sent through the scope sync feature. This causes duplicate breadcrumbs.
-      We then remove the breadcrumbs in all cases but if it is handled == false,
-      this is a signal that the app would crash and android would lose the breadcrumbs by the time the app is restarted to read
-      the envelope.
-      */
-      preparedEvent = _eventWithRemovedBreadcrumbsIfHandled(preparedEvent);
-    }
+    preparedEvent = _eventWithoutBreadcrumbsIfNeeded(preparedEvent);
 
     var attachments = List<SentryAttachment>.from(scope?.attachments ?? []);
     var screenshot = hint.screenshot;
@@ -329,6 +318,9 @@ class SentryClient {
       return _sentryId;
     }
 
+    preparedTransaction =
+        _transactionWithoutBreadcrumbsIfNeeded(preparedTransaction);
+
     final attachments = scope?.attachments
         .where((element) => element.addToTransactions)
         .toList();
@@ -462,18 +454,43 @@ class SentryClient {
     _options.recorder.recordLostEvent(reason, category);
   }
 
-  SentryEvent _eventWithRemovedBreadcrumbsIfHandled(SentryEvent event) {
+  SentryEvent _eventWithoutBreadcrumbsIfNeeded(SentryEvent event) {
+    if (_shouldRemoveBreadcrumbs(event)) {
+      return event.copyWith(breadcrumbs: []);
+    } else {
+      return event;
+    }
+  }
+
+  SentryTransaction _transactionWithoutBreadcrumbsIfNeeded(
+      SentryTransaction transaction) {
+    if (_shouldRemoveBreadcrumbs(transaction)) {
+      return transaction.copyWith(breadcrumbs: []);
+    } else {
+      return transaction;
+    }
+  }
+
+  /// We do this to avoid duplicate breadcrumbs on Android as sentry-android applies the breadcrumbs
+  /// from the native scope onto every envelope sent through it. This scope will contain the breadcrumbs
+  /// sent through the scope sync feature. This causes duplicate breadcrumbs.
+  /// We then remove the breadcrumbs in all cases but if it is handled == false,
+  /// this is a signal that the app would crash and android would lose the breadcrumbs by the time the app is restarted to read
+  /// the envelope.
+  bool _shouldRemoveBreadcrumbs(SentryEvent event) {
+    final isAndroid = _options.platformChecker.platform.isAndroid;
+    final enableScopeSync = _options.enableScopeSync;
+
+    if (!isAndroid || !enableScopeSync) {
+      return false;
+    }
+
     final mechanisms =
         (event.exceptions ?? []).map((e) => e.mechanism).whereType<Mechanism>();
     final hasNoMechanism = mechanisms.isEmpty;
     final hasOnlyHandledMechanism =
         mechanisms.every((e) => (e.handled ?? true));
-
-    if (hasNoMechanism || hasOnlyHandledMechanism) {
-      return event.copyWith(breadcrumbs: []);
-    } else {
-      return event;
-    }
+    return hasNoMechanism || hasOnlyHandledMechanism;
   }
 
   Future<SentryId?> _attachClientReportsAndSend(SentryEnvelope envelope) {

dart/test/sentry_client_test.dart

@@ -1154,7 +1154,28 @@ void main() {
       fixture = Fixture();
     });
 
-    test('Clears breadcrumbs on Android if mechanism.handled is true',
+    test('Clears breadcrumbs on Android for transaction', () async {
+      fixture.options.enableScopeSync = true;
+      fixture.options.platformChecker =
+          MockPlatformChecker(platform: MockPlatform.android());
+
+      final client = fixture.getSut();
+      final transaction = SentryTransaction(
+        fixture.tracer,
+        breadcrumbs: [
+          Breadcrumb(),
+        ],
+      );
+      await client.captureTransaction(transaction);
+
+      final capturedEnvelope = (fixture.transport).envelopes.first;
+      final capturedTransaction =
+          await transactionFromEnvelope(capturedEnvelope);
+
+      expect((capturedTransaction['breadcrumbs'] ?? []).isEmpty, true);
+    });
+
+    test('Clears breadcrumbs on Android if mechanism.handled is true for event',
         () async {
       fixture.options.enableScopeSync = true;
       fixture.options.platformChecker =
@@ -1181,7 +1202,7 @@ void main() {
       expect((capturedEvent.breadcrumbs ?? []).isEmpty, true);
     });
 
-    test('Clears breadcrumbs on Android if mechanism.handled is null',
+    test('Clears breadcrumbs on Android if mechanism.handled is null for event',
         () async {
       fixture.options.enableScopeSync = true;
       fixture.options.platformChecker =
@@ -1205,7 +1226,8 @@ void main() {
       expect((capturedEvent.breadcrumbs ?? []).isEmpty, true);
     });
 
-    test('Clears breadcrumbs on Android if theres no mechanism', () async {
+    test('Clears breadcrumbs on Android if theres no mechanism for event',
+        () async {
       fixture.options.enableScopeSync = true;
       fixture.options.platformChecker =
           MockPlatformChecker(platform: MockPlatform.android());
@@ -1227,7 +1249,8 @@ void main() {
       expect((capturedEvent.breadcrumbs ?? []).isEmpty, true);
     });
 
-    test('Does not clear breadcrumbs on Android if mechanism.handled is false',
+    test(
+        'Does not clear breadcrumbs on Android if mechanism.handled is false for event',
         () async {
       fixture.options.enableScopeSync = true;
       fixture.options.platformChecker =
@@ -1255,7 +1278,7 @@ void main() {
     });
 
     test(
-        'Does not clear breadcrumbs on Android if any mechanism.handled is false',
+        'Does not clear breadcrumbs on Android if any mechanism.handled is false for event',
         () async {
       fixture.options.enableScopeSync = true;
       fixture.options.platformChecker =

flutter/example/lib/main.dart

@@ -137,6 +137,23 @@ class MainScaffold extends StatelessWidget {
         child: Column(
           children: [
             const Center(child: Text('Trigger an action:\n')),
+            ElevatedButton(
+              onPressed: () async {
+                final transaction = Sentry.getSpan()?.startChild('foo') ??
+                    Sentry.startTransaction(
+                      'foo',
+                      'op',
+                      bindToScope: true,
+                    );
+
+                final crumb = Breadcrumb(message: "bar");
+                Sentry.addBreadcrumb(crumb);
+
+                await Future.delayed(
+                    const Duration(seconds: 2), transaction.finish);
+              },
+              child: const Text('Duplicate Transaction Breadcrumbs'),
+            ),
             ElevatedButton(
               onPressed: () => sqfliteTest(),
               child: const Text('sqflite'),