fix(crashlytics, iOS): reorder error reason logging to match Android implementation

packages/firebase_crashlytics/firebase_crashlytics/android/src/main/java/io/flutter/plugins/firebase/crashlytics/FlutterFirebaseCrashlyticsPlugin.java

@@ -21,6 +21,7 @@
 import com.google.firebase.crashlytics.internal.Logger;
 import io.flutter.embedding.engine.plugins.FlutterPlugin;
 import io.flutter.plugin.common.BinaryMessenger;
+import io.flutter.plugin.common.EventChannel;
 import io.flutter.plugin.common.MethodCall;
 import io.flutter.plugin.common.MethodChannel;
 import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
@@ -34,9 +35,11 @@
 
 /** FlutterFirebaseCrashlyticsPlugin */
 public class FlutterFirebaseCrashlyticsPlugin
-    implements FlutterFirebasePlugin, FlutterPlugin, MethodCallHandler {
+    implements FlutterFirebasePlugin, FlutterPlugin, MethodCallHandler, EventChannel.StreamHandler {
   public static final String TAG = "FLTFirebaseCrashlytics";
   private MethodChannel channel;
+  private EventChannel testEventChannel;
+  private EventChannel.EventSink testEventSink;
 
   private static final String FIREBASE_CRASHLYTICS_COLLECTION_ENABLED =
       "firebase_crashlytics_collection_enabled";
@@ -46,6 +49,9 @@ private void initInstance(BinaryMessenger messenger) {
     channel = new MethodChannel(messenger, channelName);
     channel.setMethodCallHandler(this);
     FlutterFirebasePluginRegistry.registerPlugin(channelName, this);
+    testEventChannel =
+        new EventChannel(messenger, "plugins.flutter.io/firebase_crashlytics_test_stream");
+    testEventChannel.setStreamHandler(this);
   }
 
   @Override
@@ -59,6 +65,10 @@ public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
       channel.setMethodCallHandler(null);
       channel = null;
     }
+    if (testEventChannel != null) {
+      testEventChannel.setStreamHandler(null);
+      testEventChannel = null;
+    }
   }
 
   private Task<Map<String, Object>> checkForUnsentReports() {
@@ -134,6 +144,7 @@ private Task<Map<String, Object>> didCrashOnPreviousExecution() {
 
   private Task<Void> recordError(final Map<String, Object> arguments) {
     TaskCompletionSource<Void> taskCompletionSource = new TaskCompletionSource<>();
+    Handler mainHandler = new Handler(Looper.getMainLooper());
 
     cachedThreadPool.execute(
         () -> {
@@ -160,8 +171,12 @@ private Task<Void> recordError(final Map<String, Object> arguments) {
 
             Exception exception;
             if (reason != null) {
+              final String crashlyticsErrorReason = "thrown " + reason;
+              if (testEventSink != null) {
+                mainHandler.post(() -> testEventSink.success(crashlyticsErrorReason));
+              }
               // Set a "reason" (to match iOS) to show where the exception was thrown.
-              crashlytics.setCustomKey(Constants.FLUTTER_ERROR_REASON, "thrown " + reason);
+              crashlytics.setCustomKey(Constants.FLUTTER_ERROR_REASON, crashlyticsErrorReason);
               exception =
                   new FlutterError(dartExceptionMessage + ". " + "Error thrown " + reason + ".");
             } else {
@@ -466,4 +481,14 @@ public Task<Void> didReinitializeFirebaseCore() {
 
     return taskCompletionSource.getTask();
   }
+
+  @Override
+  public void onListen(Object arguments, EventChannel.EventSink events) {
+    testEventSink = events;
+  }
+
+  @Override
+  public void onCancel(Object arguments) {
+    testEventSink = null;
+  }
 }

packages/firebase_crashlytics/firebase_crashlytics/ios/firebase_crashlytics/Sources/firebase_crashlytics/FLTFirebaseCrashlyticsPlugin.m

@@ -15,6 +15,8 @@
 #endif
 
 NSString *const kFLTFirebaseCrashlyticsChannelName = @"plugins.flutter.io/firebase_crashlytics";
+NSString *const kFLTFirebaseCrashlyticsTestChannelName =
+    @"plugins.flutter.io/firebase_crashlytics_test_stream";
 
 // Argument Keys
 NSString *const kCrashlyticsArgumentException = @"exception";
@@ -34,6 +36,11 @@
 NSString *const kCrashlyticsArgumentUnsentReports = @"unsentReports";
 NSString *const kCrashlyticsArgumentDidCrashOnPreviousExecution = @"didCrashOnPreviousExecution";
 
+@interface FLTFirebaseCrashlyticsPlugin () <FlutterStreamHandler>
+@property(nonatomic, strong) FlutterEventChannel *testEventChannel;
+@property(nonatomic, strong) FlutterEventSink testEventSink;
+@end
+
 @implementation FLTFirebaseCrashlyticsPlugin
 
 #pragma mark - FlutterPlugin
@@ -61,6 +68,10 @@ + (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
                                   binaryMessenger:[registrar messenger]];
   FLTFirebaseCrashlyticsPlugin *instance = [FLTFirebaseCrashlyticsPlugin sharedInstance];
   [registrar addMethodCallDelegate:instance channel:channel];
+  instance.testEventChannel =
+      [FlutterEventChannel eventChannelWithName:kFLTFirebaseCrashlyticsTestChannelName
+                                binaryMessenger:[registrar messenger]];
+  [instance.testEventChannel setStreamHandler:instance];
 }
 
 - (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)flutterResult {
@@ -126,10 +137,15 @@ - (void)recordError:(id)arguments withMethodCallResult:(FLTFirebaseMethodCallRes
   }
 
   if (![reason isEqual:[NSNull null]]) {
-    reason = [NSString stringWithFormat:@"%@. Error thrown %@.", dartExceptionMessage, reason];
+    NSString *crashlyticsErrorReason = [NSString stringWithFormat:@"thrown %@", reason];
+
+    if (self.testEventSink) {
+      self.testEventSink(crashlyticsErrorReason);
+    }
     // Log additional custom value to match Android.
-    [[FIRCrashlytics crashlytics] setCustomValue:[NSString stringWithFormat:@"thrown %@", reason]
+    [[FIRCrashlytics crashlytics] setCustomValue:crashlyticsErrorReason
                                           forKey:@"flutter_error_reason"];
+    reason = [NSString stringWithFormat:@"%@. Error thrown %@.", dartExceptionMessage, reason];
   } else {
     reason = dartExceptionMessage;
   }
@@ -247,4 +263,15 @@ - (NSString *_Nonnull)flutterChannelName {
   return kFLTFirebaseCrashlyticsChannelName;
 }
 
+- (FlutterError *_Nullable)onCancelWithArguments:(id _Nullable)arguments {
+  self.testEventSink = nil;
+  return nil;
+}
+
+- (FlutterError *_Nullable)onListenWithArguments:(id _Nullable)arguments
+                                       eventSink:(nonnull FlutterEventSink)events {
+  self.testEventSink = events;
+  return nil;
+}
+
 @end

tests/integration_test/firebase_crashlytics/firebase_crashlytics_e2e_test.dart

@@ -5,9 +5,11 @@
 import 'package:firebase_core/firebase_core.dart';
 import 'package:firebase_crashlytics/firebase_crashlytics.dart';
 import 'package:flutter/foundation.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:integration_test/integration_test.dart';
 import 'package:tests/firebase_options.dart';
+import 'dart:async';
 
 void main() {
   IntegrationTestWidgetsFlutterBinding.ensureInitialized();
@@ -98,6 +100,31 @@ void main() {
             );
           },
         );
+
+        test(
+          'should have consistent error reason format',
+          () async {
+              const eventChannel = EventChannel('plugins.flutter.io/firebase_crashlytics_test_stream');
+              final eventStream = eventChannel.receiveBroadcastStream();  
+
+              final completer = Completer<String>();
+
+              final subscription = eventStream.listen((event) {
+                completer.complete(event.toString());
+              });
+
+              await FirebaseCrashlytics.instance.recordError(
+                'foo exception',
+                StackTrace.fromString('during testing'),
+                reason: 'foo reason',
+              );
+
+              final event = await completer.future;
+              expect(event, 'thrown foo reason');
+              await subscription.cancel();
+          },
+          skip: kIsWeb || defaultTargetPlatform == TargetPlatform.macOS,
+        );
       });
 
       group('log', () {