Feat: debugPrint integration

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Unreleased
 
 * Feat: Add current route as transaction (#615)
+* Feat: Add Breadcrumbs for Flutters `debugPrint` (#618)
 
 # 6.1.0-alpha.2
 

dart/lib/src/default_integrations.dart

@@ -67,11 +67,9 @@ class RunZonedGuardedIntegration extends Integration {
           _isPrinting = true;
 
           try {
-            hub.addBreadcrumb(Breadcrumb(
+            hub.addBreadcrumb(Breadcrumb.console(
               message: line,
               level: SentryLevel.debug,
-              category: 'console',
-              type: 'debug',
             ));
 
             parent.print(zone, line);

dart/lib/src/protocol/breadcrumb.dart

@@ -66,6 +66,22 @@ class Breadcrumb {
     );
   }
 
+  factory Breadcrumb.console({
+    String? message,
+    SentryLevel? level,
+    DateTime? timestamp,
+    Map<String, dynamic>? data,
+  }) {
+    return Breadcrumb(
+      message: message,
+      level: level,
+      category: 'console',
+      type: 'debug',
+      timestamp: timestamp,
+      data: data,
+    );
+  }
+
   /// Describes the breadcrumb.
   ///
   /// This field is optional and may be set to null.

dart/test/protocol/breadcrumb_test.dart

@@ -128,4 +128,37 @@ void main() {
       'type': 'http',
     });
   });
+
+  test('Breadcrumb console ctor', () {
+    final breadcrumb = Breadcrumb.console(
+      message: 'Foo Bar',
+    );
+    final json = breadcrumb.toJson();
+
+    expect(json, {
+      'message': 'Foo Bar',
+      'timestamp': formatDateAsIso8601WithMillisPrecision(breadcrumb.timestamp),
+      'category': 'console',
+      'type': 'debug',
+      'level': 'info',
+    });
+  });
+
+  test('extensive Breadcrumb console ctor', () {
+    final breadcrumb = Breadcrumb.console(
+      message: 'Foo Bar',
+      level: SentryLevel.error,
+      data: {'foo': 'bar'},
+    );
+    final json = breadcrumb.toJson();
+
+    expect(json, {
+      'message': 'Foo Bar',
+      'timestamp': formatDateAsIso8601WithMillisPrecision(breadcrumb.timestamp),
+      'category': 'console',
+      'type': 'debug',
+      'level': 'error',
+      'data': {'foo': 'bar'},
+    });
+  });
 }

flutter/lib/src/integrations/debug_print_integration.dart

@@ -0,0 +1,66 @@
+import 'dart:async';
+
+import 'package:flutter/foundation.dart';
+import 'package:sentry/sentry.dart';
+
+import '../sentry_flutter_options.dart';
+
+/// Integration which intercepts Flutters [debugPrint] method.
+/// If this integration is added, all calls to [debugPrint] a redirected to
+/// add a [Breadcrumb]. [debugPrint] is not outputting to the console anymore!
+/// This integration fixes the issue described in
+/// [#492](https://github.com/getsentry/sentry-dart/issues/492).
+class DebugPrintIntegration extends Integration<SentryFlutterOptions> {
+  DebugPrintCallback? _debugPrintBackup;
+  late Hub _hub;
+  late SentryFlutterOptions _options;
+
+  @override
+  FutureOr<void> call(Hub hub, SentryFlutterOptions options) {
+    _hub = hub;
+    _options = options;
+
+    final isDebug = options.platformChecker.isDebugMode();
+    final enablePrintBreadcrumbs = options.enablePrintBreadcrumbs;
+    if (isDebug || !enablePrintBreadcrumbs) {
+      return Future.value();
+    }
+
+    _debugPrintBackup = debugPrint;
+
+    // We're simply replacing debugPrint here. The default implementation is a
+    // a throttling system which prints using Darts print method. It's basically
+    // a fire and forget method which completes sometime in the future. We can't
+    // observe when it's done.
+    //
+    // This makes it impossible to just disable adding print() breadcrumbs
+    // before debugPrint is called and re-enable it after debugPrint was called.
+    // See the docs for more information.
+    // https://api.flutter.dev/flutter/foundation/debugPrint.html
+    debugPrint = _debugPrint;
+
+    options.sdk.addIntegration('debugPrintIntegration');
+  }
+
+  @override
+  void close() {
+    if (_debugPrintBackup != null) {
+      debugPrint = _debugPrintBackup!;
+    }
+  }
+
+  void _debugPrint(String? message, {int? wrapWidth}) {
+    if (message == null) {
+      _options.logger(
+        SentryLevel.debug,
+        'debugPrint Integration received "null" as message. '
+        'The message is dropped.',
+      );
+      return;
+    }
+    _hub.addBreadcrumb(Breadcrumb.console(
+      message: message,
+      level: SentryLevel.debug,
+    ));
+  }
+}

flutter/lib/src/sentry_flutter.dart

@@ -5,6 +5,7 @@ import 'package:package_info_plus/package_info_plus.dart';
 import 'package:sentry/sentry.dart';
 
 import 'flutter_enricher_event_processor.dart';
+import 'integrations/debug_print_integration.dart';
 import 'sentry_flutter_options.dart';
 
 import 'default_integrations.dart';
@@ -107,6 +108,8 @@ mixin SentryFlutter {
       integrations.add(LoadAndroidImageListIntegration(channel));
     }
 
+    integrations.add(DebugPrintIntegration());
+
     // This is an Integration because we want to execute it after all the
     // error handlers are in place. Calling a MethodChannel might result
     // in errors.

flutter/test/integrations/debug_print_integration_test.dart

@@ -0,0 +1,106 @@
+import 'package:flutter/foundation.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/mockito.dart';
+import 'package:sentry_flutter/sentry_flutter.dart';
+import 'package:sentry_flutter/src/integrations/debug_print_integration.dart';
+
+import '../mocks.dart';
+import '../mocks.mocks.dart';
+
+void main() {
+  late Fixture fixture;
+
+  setUp(() {
+    fixture = Fixture();
+  });
+
+  tearDown(() {
+    debugPrint = debugPrintSynchronously;
+  });
+
+  test('$DebugPrintIntegration: debugPrint adds a breadcrumb', () {
+    final integration = fixture.getSut();
+    integration.call(fixture.hub, fixture.getOptions());
+
+    debugPrint('Foo Bar');
+
+    final breadcrumb = verify(
+      fixture.hub.addBreadcrumb(captureAny),
+    ).captured.first as Breadcrumb;
+
+    expect(breadcrumb.message, 'Foo Bar');
+  });
+
+  test(
+      '$DebugPrintIntegration: debugPrint does not add a breadcrumb after close',
+      () {
+    final integration = fixture.getSut();
+    integration.call(fixture.hub, fixture.getOptions());
+    integration.close();
+
+    debugPrint('Foo Bar');
+
+    verifyNever(fixture.hub.addBreadcrumb(captureAny));
+  });
+
+  test(
+      '$DebugPrintIntegration: close changes debugPrint back to default implementation',
+      () {
+    final original = debugPrint;
+
+    final integration = fixture.getSut();
+    integration.call(fixture.hub, fixture.getOptions());
+    integration.close();
+
+    expect(debugPrint, original);
+  });
+
+  test('$DebugPrintIntegration: disabled in debug builds', () {
+    final integration = fixture.getSut();
+    integration.call(fixture.hub, fixture.getOptions(debug: true));
+
+    debugPrint('Foo Bar');
+
+    verifyNever(fixture.hub.addBreadcrumb(captureAny));
+  });
+
+  test('$DebugPrintIntegration: disabled if enablePrintBreadcrumbs = false',
+      () {
+    final integration = fixture.getSut();
+    integration.call(
+      fixture.hub,
+      fixture.getOptions(enablePrintBreadcrumbs: false),
+    );
+
+    debugPrint('Foo Bar');
+
+    verifyNever(fixture.hub.addBreadcrumb(captureAny));
+  });
+
+  test(
+      '$DebugPrintIntegration: close works if debugPrintIntegration.call was not called',
+      () {
+    final integration = fixture.getSut();
+
+    // test is successful if no exception is thrown
+    expect(() => integration.close(), returnsNormally);
+  });
+}
+
+class Fixture {
+  final hub = MockHub();
+
+  SentryFlutterOptions getOptions({
+    bool debug = false,
+    bool enablePrintBreadcrumbs = true,
+  }) {
+    return SentryFlutterOptions(
+      dsn: fakeDsn,
+      checker: MockPlatformChecker(isDebug: debug),
+    )..enablePrintBreadcrumbs = enablePrintBreadcrumbs;
+  }
+
+  DebugPrintIntegration getSut() {
+    return DebugPrintIntegration();
+  }
+}

flutter/test/sentry_flutter_test.dart

@@ -4,6 +4,7 @@ import 'package:package_info_plus/package_info_plus.dart';
 import 'package:sentry/sentry.dart';
 import 'package:sentry_flutter/sentry_flutter.dart';
 import 'package:sentry/src/platform_checker.dart';
+import 'package:sentry_flutter/src/integrations/debug_print_integration.dart';
 import 'package:sentry_flutter/src/version.dart';
 import 'mocks.dart';
 import 'sentry_flutter_util.dart';
@@ -13,6 +14,7 @@ import 'sentry_flutter_util.dart';
 final platformAgnosticIntegrations = [
   FlutterErrorIntegration,
   LoadReleaseIntegration,
+  DebugPrintIntegration,
 ];
 
 // These should only be added to Android