Refactoring: Dart Nullsafety (#298)

.github/workflows/dart.yml

@@ -20,7 +20,7 @@ jobs:
         # TODO: cedx/setup-dart@v2 doesn't work on Windows (doesn't add pub to the PATH?)
         # os: [ubuntu-latest, windows-latest, macos-latest]
         os: [ubuntu-latest, macos-latest]
-        sdk: [beta, dev, stable]
+        sdk: [beta, dev]
         exclude:
           # Bad state: Could not run tests with Observatory enabled. Try setting a different port with --port option.
           - os: ubuntu-latest
@@ -61,7 +61,7 @@ jobs:
     steps:
       - uses: cedx/setup-dart@v2
         with:
-          release-channel: stable
+          release-channel: beta
       - uses: actions/checkout@v2
       - run: |
           dart pub get

.github/workflows/flutter.yml

@@ -17,7 +17,7 @@ jobs:
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
         target: ['ios', 'android', 'web']
-        channel: ['stable', 'beta']
+        channel: ['beta']
         exclude:
           - os: ubuntu-latest
             target: ios

CHANGELOG.md

@@ -1,5 +1,6 @@
 # vNext
 
+* Refactoring: Migrate Sentry Dart to null safety
 * Fix: captureMessage defaults SentryLevel to info
 
 # 4.0.5

dart/example/main.dart

@@ -85,7 +85,7 @@ Future<void> runApp() async {
 
     print('Capture exception result : SentryId : $sentryId');
   } finally {
-    await Sentry.close();
+    Sentry.close();
   }
 }
 

dart/lib/src/http_client/sentry_http_client.dart

@@ -46,13 +46,12 @@ import '../../sentry.dart';
 // For example with Darts Stopwatch:
 // https://api.dart.dev/stable/2.10.4/dart-core/Stopwatch-class.html
 class SentryHttpClient extends BaseClient {
-  SentryHttpClient({Client client, Hub hub}) {
-    _hub = hub ?? HubAdapter();
-    _client = client ?? Client();
-  }
+  SentryHttpClient({Client? client, Hub? hub})
+      : _hub = hub ?? HubAdapter(),
+        _client = client ?? Client();
 
-  Client _client;
-  Hub _hub;
+  final Client _client;
+  final Hub _hub;
 
   @override
   Future<StreamedResponse> send(BaseRequest request) async {

dart/lib/src/hub.dart

@@ -1,7 +1,6 @@
 import 'dart:async';
 import 'dart:collection';
 
-import 'noop_sentry_client.dart';
 import 'protocol.dart';
 import 'scope.dart';
 import 'sentry_client.dart';
@@ -18,8 +17,9 @@ class Hub {
 
   final ListQueue<_StackItem> _stack = ListQueue();
 
-  /// if stack is empty, it throws IterableElementError.noElement()
-  _StackItem _peek() => _stack.isNotEmpty ? _stack.first : null;
+  // peek can never return null since Stack can be created only with an item and
+  // pop does not drop the last item.
+  _StackItem _peek() => _stack.first;
 
   final SentryOptions _options;
 
@@ -35,11 +35,7 @@ class Hub {
   }
 
   static void _validateOptions(SentryOptions options) {
-    if (options == null) {
-      throw ArgumentError('SentryOptions is required.');
-    }
-
-    if (options.dsn?.isNotEmpty != true) {
+    if (options.dsn == null) {
       throw ArgumentError('DSN is required.');
     }
   }
@@ -67,34 +63,23 @@ class Hub {
         SentryLevel.warning,
         "Instance is disabled and this 'captureEvent' call is a no-op.",
       );
-    } else if (event == null) {
-      _options.logger(
-        SentryLevel.warning,
-        'captureEvent called with null parameter.',
-      );
     } else {
       final item = _peek();
-      if (item != null) {
-        try {
-          sentryId = await item.client.captureEvent(
-            event,
-            stackTrace: stackTrace,
-            scope: item.scope,
-            hint: hint,
-          );
-        } catch (err) {
-          _options.logger(
-            SentryLevel.error,
-            'Error while capturing event with id: ${event.eventId.toString()}',
-          );
-        } finally {
-          _lastEventId = sentryId;
-        }
-      } else {
+
+      try {
+        sentryId = await item.client.captureEvent(
+          event,
+          stackTrace: stackTrace,
+          scope: item.scope,
+          hint: hint,
+        );
+      } catch (err) {
         _options.logger(
-          SentryLevel.fatal,
-          'Stack peek was null when captureEvent',
+          SentryLevel.error,
+          'Error while capturing event with id: ${event.eventId.toString()}',
         );
+      } finally {
+        _lastEventId = sentryId;
       }
     }
     return sentryId;
@@ -120,27 +105,21 @@ class Hub {
       );
     } else {
       final item = _peek();
-      if (item != null) {
-        try {
-          sentryId = await item.client.captureException(
-            throwable,
-            stackTrace: stackTrace,
-            scope: item.scope,
-            hint: hint,
-          );
-        } catch (err) {
-          _options.logger(
-            SentryLevel.error,
-            'Error while capturing exception : $throwable',
-          );
-        } finally {
-          _lastEventId = sentryId;
-        }
-      } else {
+
+      try {
+        sentryId = await item.client.captureException(
+          throwable,
+          stackTrace: stackTrace,
+          scope: item.scope,
+          hint: hint,
+        );
+      } catch (err) {
         _options.logger(
-          SentryLevel.fatal,
-          'Stack peek was null when captureException',
+          SentryLevel.error,
+          'Error while capturing exception : $throwable',
         );
+      } finally {
+        _lastEventId = sentryId;
       }
     }
 
@@ -149,10 +128,10 @@ class Hub {
 
   /// Captures the message.
   Future<SentryId> captureMessage(
-    String message, {
-    SentryLevel level,
-    String template,
-    List<dynamic> params,
+    String? message, {
+    SentryLevel? level,
+    String? template,
+    List<dynamic>? params,
     dynamic hint,
   }) async {
     var sentryId = SentryId.empty();
@@ -169,29 +148,23 @@ class Hub {
       );
     } else {
       final item = _peek();
-      if (item != null) {
-        try {
-          sentryId = await item.client.captureMessage(
-            message,
-            level: level,
-            template: template,
-            params: params,
-            scope: item.scope,
-            hint: hint,
-          );
-        } catch (err) {
-          _options.logger(
-            SentryLevel.error,
-            'Error while capturing message with id: $message',
-          );
-        } finally {
-          _lastEventId = sentryId;
-        }
-      } else {
+
+      try {
+        sentryId = await item.client.captureMessage(
+          message,
+          level: level,
+          template: template,
+          params: params,
+          scope: item.scope,
+          hint: hint,
+        );
+      } catch (err) {
         _options.logger(
-          SentryLevel.fatal,
-          'Stack peek was null when captureMessage',
+          SentryLevel.error,
+          'Error while capturing message with id: $message',
         );
+      } finally {
+        _lastEventId = sentryId;
       }
     }
     return sentryId;
@@ -204,21 +177,9 @@ class Hub {
         SentryLevel.warning,
         "Instance is disabled and this 'addBreadcrumb' call is a no-op.",
       );
-    } else if (crumb == null) {
-      _options.logger(
-        SentryLevel.warning,
-        'addBreadcrumb called with null parameter.',
-      );
     } else {
       final item = _peek();
-      if (item != null) {
-        item.scope.addBreadcrumb(crumb, hint: hint);
-      } else {
-        _options.logger(
-          SentryLevel.fatal,
-          'Stack peek was null when addBreadcrumb',
-        );
-      }
+      item.scope.addBreadcrumb(crumb, hint: hint);
     }
   }
 
@@ -229,20 +190,8 @@ class Hub {
           "Instance is disabled and this 'bindClient' call is a no-op.");
     } else {
       final item = _peek();
-      if (item != null) {
-        if (client != null) {
-          _options.logger(SentryLevel.debug, 'New client bound to scope.');
-          item.client = client;
-        } else {
-          _options.logger(SentryLevel.debug, 'NoOp client bound to scope.');
-          item.client = NoOpSentryClient();
-        }
-      } else {
-        _options.logger(
-          SentryLevel.fatal,
-          'Stack peek was null when bindClient',
-        );
-      }
+      _options.logger(SentryLevel.debug, 'New client bound to scope.');
+      item.client = client;
     }
   }
 
@@ -272,21 +221,15 @@ class Hub {
       }
 
       final item = _peek();
-      if (item != null) {
-        try {
-          item.client.close();
-        } catch (err) {
-          _options.logger(
-            SentryLevel.error,
-            'Error while closing the Hub.',
-          );
-        }
-      } else {
+      try {
+        item.client.close();
+      } catch (err) {
         _options.logger(
-          SentryLevel.fatal,
-          'Stack peek was NULL when closing Hub',
+          SentryLevel.error,
+          'Error while closing the Hub.',
         );
       }
+
       _isEnabled = false;
     }
   }
@@ -300,19 +243,13 @@ class Hub {
       );
     } else {
       final item = _peek();
-      if (item != null) {
-        try {
-          callback(item.scope);
-        } catch (err) {
-          _options.logger(
-            SentryLevel.error,
-            "Error in the 'configureScope' callback.",
-          );
-        }
-      } else {
+
+      try {
+        callback(item.scope);
+      } catch (err) {
         _options.logger(
-          SentryLevel.fatal,
-          'Stack peek was NULL when configureScope',
+          SentryLevel.error,
+          "Error in the 'configureScope' callback.",
         );
       }
     }

dart/lib/src/hub_adapter.dart

@@ -48,10 +48,10 @@ class HubAdapter implements Hub {
 
   @override
   Future<SentryId> captureMessage(
-    String message, {
-    SentryLevel level,
-    String template,
-    List params,
+    String? message, {
+    SentryLevel? level,
+    String? template,
+    List? params,
     dynamic hint,
   }) =>
       Sentry.captureMessage(

dart/lib/src/isolate_error_integration.dart

@@ -10,7 +10,7 @@ import 'sentry_options.dart';
 import 'throwable_mechanism.dart';
 
 class IsolateErrorIntegration extends Integration {
-  RawReceivePort _receivePort;
+  late RawReceivePort _receivePort;
 
   @override
   FutureOr<void> call(Hub hub, SentryOptions options) async {