Fix: EventProcessors were not dropping events when returning null

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 * Bump: sentry-android to v4.3.0 (#343)
 * Fix: Multiple FlutterError.onError calls in FlutterErrorIntegration (#345)
+* Fix: EventProcessors were not dropping events when returning null (#353)
 
 # 4.1.0-nullsafety.0
 

dart/lib/src/scope.dart

@@ -182,7 +182,7 @@ class Scope {
     SentryEvent? processedEvent = event;
     for (final processor in _eventProcessors) {
       try {
-        processedEvent = await processor(processedEvent!, hint: hint)!;
+        processedEvent = await processor(processedEvent!, hint: hint);
       } catch (err) {
         _options.logger(
           SentryLevel.error,

dart/lib/src/sentry_client.dart

@@ -179,7 +179,7 @@ class SentryClient {
     SentryEvent? processedEvent = event;
     for (final processor in eventProcessors) {
       try {
-        processedEvent = await processor(processedEvent!, hint: hint)!;
+        processedEvent = await processor(processedEvent!, hint: hint);
       } catch (err) {
         _options.logger(
           SentryLevel.error,

dart/test/scope_test.dart

@@ -404,6 +404,17 @@ void main() {
       expect(updatedEvent?.level, SentryLevel.error);
     });
   });
+
+  test('event processor drops the event', () async {
+    final sut = fixture.getSut();
+
+    sut.addEventProcessor(fixture.processor);
+
+    final event = SentryEvent();
+    var newEvent = await sut.applyToEvent(event, null);
+
+    expect(newEvent, isNull);
+  });
 }
 
 class Fixture {

dart/test/sentry_client_test.dart

@@ -507,6 +507,14 @@ void main() {
       );
       expect(event.fingerprint!.contains('process'), true);
     });
+
+    test('event processor drops the event', () async {
+      options.addEventProcessor(eventProcessorDropEvent);
+      final client = SentryClient(options);
+      await client.captureEvent(fakeEvent);
+
+      expect((options.transport as MockTransport).called(0), true);
+    });
   });
 }
 
@@ -523,3 +531,7 @@ SentryEvent beforeSendCallback(SentryEvent event, {dynamic hint}) {
     ..sdk!.addIntegration('testIntegration')
     ..sdk!.addPackage('test-pkg', '1.0');
 }
+
+SentryEvent? eventProcessorDropEvent(SentryEvent event, {dynamic hint}) {
+  return null;
+}