[iOS] Add FlutterViewController weak pointer check before use (#31008)

zhongwuzw · web-flow · commit 23c2bd69d017 · 2022-02-03T19:55:10.000-08:00
diff --git a/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm b/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm
@@ -673,7 +673,9 @@ - (void)addInternalPlugins {
   fml::WeakPtr<FlutterViewController> weakSelf = [self getWeakPtr];
   FlutterSendKeyEvent sendEvent =
       ^(const FlutterKeyEvent& event, FlutterKeyEventCallback callback, void* userData) {
-        [weakSelf.get()->_engine.get() sendKeyEvent:event callback:callback userData:userData];
+        if (weakSelf) {
+          [weakSelf.get()->_engine.get() sendKeyEvent:event callback:callback userData:userData];
+        }
       };
   [self.keyboardManager addPrimaryResponder:[[[FlutterEmbedderKeyResponder alloc]
                                                 initWithSendEvent:sendEvent] autorelease]];
diff --git a/shell/platform/darwin/ios/framework/Source/FlutterViewControllerTest.mm b/shell/platform/darwin/ios/framework/Source/FlutterViewControllerTest.mm
@@ -10,6 +10,7 @@
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterBinaryMessenger.h"
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterMacros.h"
 #import "flutter/shell/platform/darwin/ios/framework/Headers/FlutterViewController.h"
+#import "flutter/shell/platform/darwin/ios/framework/Source/FlutterEmbedderKeyResponder.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterFakeKeyEvents.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterTextInputPlugin.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterViewController_Internal.h"
@@ -116,6 +117,15 @@ - (UIAccessibilityContrast)accessibilityContrast;
 @end
 #endif
 
+@interface FlutterKeyboardManager (Tests)
+@property(nonatomic, retain, readonly)
+    NSMutableArray<id<FlutterKeyPrimaryResponder>>* primaryResponders;
+@end
+
+@interface FlutterEmbedderKeyResponder (Tests)
+@property(nonatomic, copy, readonly) FlutterSendKeyEvent sendEvent;
+@end
+
 @interface FlutterViewController (Tests)
 - (void)surfaceUpdated:(BOOL)appeared;
 - (void)performOrientationUpdate:(UIInterfaceOrientationMask)new_preferences;
@@ -130,6 +140,7 @@ - (void)keyboardWillChangeFrame:(NSNotification*)notification;
 - (void)startKeyBoardAnimation:(NSTimeInterval)duration;
 - (void)ensureViewportMetricsIsCorrect;
 - (void)invalidateDisplayLink;
+- (void)addInternalPlugins;
 @end
 
 @interface FlutterViewControllerTest : XCTestCase
@@ -392,6 +403,24 @@ - (void)testViewDidLoadDoesInvokeEngineWhenIsTheViewController {
   OCMVerify([mockEngine attachView]);
 }
 
+- (void)testInternalPluginsWeakPtrNotCrash {
+  FlutterSendKeyEvent sendEvent;
+  @autoreleasepool {
+    FlutterViewController* vc = [[FlutterViewController alloc] initWithProject:nil
+                                                                       nibName:nil
+                                                                        bundle:nil];
+    [vc addInternalPlugins];
+    FlutterKeyboardManager* keyboardManager = vc.keyboardManager;
+    FlutterEmbedderKeyResponder* keyPrimaryResponder = (FlutterEmbedderKeyResponder*)
+        [(NSArray<id<FlutterKeyPrimaryResponder>>*)keyboardManager.primaryResponders firstObject];
+    sendEvent = [keyPrimaryResponder sendEvent];
+  }
+
+  if (sendEvent) {
+    sendEvent({}, nil, nil);
+  }
+}
+
 - (void)testBinaryMessenger {
   FlutterViewController* vc = [[FlutterViewController alloc] initWithEngine:self.mockEngine
                                                                     nibName:nil
