fix: app starts hanging for 30s (#2140)

* Update

* Update

* Add CHANGELOG

* Update comment

* Update CHANGELOG.md

Author: buenaflor

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## Unreleased
+
+### Fixes
+
+- App starts hanging for 30s ([#2140](https://github.com/getsentry/sentry-dart/pull/2140))
+  - Time out for app start info retrieval has been reduced to 10s
+  - If `autoAppStarts` is `false` and `setAppStartEnd` has not been called, the app start event processor will now return early instead of waiting for `getAppStartInfo` to finish
+
 ## 8.4.0-beta.1
 
 ### Features

flutter/lib/src/event_processor/native_app_start_event_processor.dart

@@ -24,16 +24,18 @@ class NativeAppStartEventProcessor implements EventProcessor {
       return event;
     }
 
-    final appStartInfo = await NativeAppStartIntegration.getAppStartInfo();
-
+    AppStartInfo? appStartInfo;
     if (!options.autoAppStart) {
       final appStartEnd = NativeAppStartIntegration.appStartEnd;
       if (appStartEnd != null) {
+        appStartInfo = await NativeAppStartIntegration.getAppStartInfo();
         appStartInfo?.end = appStartEnd;
       } else {
         // If autoAppStart is disabled and appStartEnd is not set, we can't add app starts
         return event;
       }
+    } else {
+      appStartInfo = await NativeAppStartIntegration.getAppStartInfo();
     }
 
     final measurement = appStartInfo?.toMeasurement();

flutter/lib/src/integrations/native_app_start_integration.dart

@@ -34,7 +34,10 @@ class NativeAppStartIntegration extends Integration<SentryFlutterOptions> {
   static bool didAddAppStartMeasurement = false;
 
   /// Timeout duration to wait for the app start info to be fetched.
-  static const _timeoutDuration = Duration(seconds: 30);
+  static const _timeoutDuration = Duration(seconds: 10);
+
+  @visibleForTesting
+  static Duration get timeoutDuration => _timeoutDuration;
 
   /// We filter out App starts more than 60s
   static const _maxAppStartMillis = 60000;

flutter/test/integrations/native_app_start_integration_test.dart

@@ -146,6 +146,30 @@ void main() {
       expect(enriched.spans.isEmpty, true);
     });
 
+    test(
+        'does not trigger timeout if autoAppStart is false and setAppStartEnd is not called',
+        () async {
+      // setting a frame callback with a bigger timeout than our app start timeout so the timeout would theoretically be triggered
+      fixture = Fixture(
+          frameCallbackTimeout: NativeAppStartIntegration.timeoutDuration +
+              const Duration(seconds: 5));
+      fixture.options.autoAppStart = false;
+
+      await fixture.registerIntegration();
+
+      final tracer = fixture.createTracer();
+      final transaction = SentryTransaction(tracer);
+
+      final processor = fixture.options.eventProcessors.first;
+
+      final stopwatch = Stopwatch()..start();
+      await processor.apply(transaction, Hint()) as SentryTransaction;
+      stopwatch.stop();
+
+      expect(stopwatch.elapsed < NativeAppStartIntegration.timeoutDuration,
+          isTrue);
+    });
+
     test(
         'autoAppStart is false and appStartEnd is set adds app start measurement',
         () async {
@@ -384,9 +408,12 @@ class Fixture extends IntegrationTestFixture<NativeAppStartIntegration> {
   @override
   MockHub get hub => super.hub as MockHub;
 
-  Fixture()
-      : super((binding) =>
-            NativeAppStartIntegration(binding, FakeFrameCallbackHandler())) {
+  Fixture({Duration? frameCallbackTimeout})
+      : super((binding) => NativeAppStartIntegration(
+            binding,
+            FakeFrameCallbackHandler(
+                finishAfterDuration: frameCallbackTimeout ??
+                    const Duration(milliseconds: 50)))) {
     NativeAppStartIntegration.reset();
     hub = MockHub();
     // ignore: invalid_use_of_internal_member