FirebaseDynamicLink crashes due to object deallocation on app launch.

[alan-andrade]

Environment

• Xcode version: 11.2
• Firebase SDK version: 6.12.0
• Firebase Component: DynamicDeeplinks
• Component version: 4.0.5

Problem

We are in the process of creating a shared framework that contains Firebase. When the framework is imported on the new app, the application crashes right away while trying to retrieve pending deeplinks.

Steps to reproduce:

1. Create a shared framework with firebase in it.
2. Import it in a new project and configure firestore on th app delegate.
3. The main application will crash.

There aren't any custom domains on the Info.plist.

Relevant Code:

Snippet from FIRDLJavaScriptExecutor.m

#pragma mark - WKNavigationDelegate

- (void)webView:(WKWebView *)webView
    didFinishNavigation:(null_unspecified WKNavigation *)navigation {
  __weak __typeof__(self) weakSelf = self;

  // Make sure that the javascript was loaded successfully before calling the method.
  [webView evaluateJavaScript:FIRDLTypeofFingerprintJSMethodNameString()
            completionHandler:^(id _Nullable typeofResult, NSError *_Nullable typeError) {
              if (typeError) {
                [weakSelf handleExecutionError:typeError];
                return;
              }
              if ([typeofResult isEqual:@"function"]) {
                [webView
                    evaluateJavaScript:GINFingerprintJSMethodString()
                     completionHandler:^(id _Nullable result, NSError *_Nullable functionError) {
                       if ([result isKindOfClass:[NSString class]]) {
                         [weakSelf handleExecutionResult:result];
                         // ^^^^^^^^ CRASH due to weakSelf being deallocated.
                       } else {
                         [weakSelf handleExecutionError:nil];
                       }
                     }];
              } else {
                [weakSelf handleExecutionError:nil];
              }
            }];
}

Stacktrace

(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x54892ed86e80)
    frame #0: 0x00007fff50bad00b libobjc.A.dylib`objc_release + 11
  * frame #1: 0x0000000109d5757f PSI`__55-[FIRDLJavaScriptExecutor webView:didFinishNavigation:]_block_invoke_2(.block_descriptor=0x0000600002839170, result=@"en-US", functionError=0x0000000000000000) at FIRDLJavaScriptExecutor.m:117:26
    frame #2: 0x00007fff2d0dec4d WebKit`WTF::Detail::CallableWrapper<-[WKWebView _evaluateJavaScript:forceUserGesture:completionHandler:]::$_7, void, API::SerializedScriptValue*, bool, WebCore::ExceptionDetails const&, WebKit::CallbackBase::Error>::call(API::SerializedScriptValue*, bool, WebCore::ExceptionDetails const&, WebKit::CallbackBase::Error) + 363
    frame #3: 0x00007fff2d173647 WebKit`WebKit::GenericCallback<API::SerializedScriptValue*, bool, WebCore::ExceptionDetails const&>::performCallbackWithReturnValue(API::SerializedScriptValue*, bool, WebCore::ExceptionDetails const&) + 41
    frame #4: 0x00007fff2d173502 WebKit`WebKit::WebPageProxy::scriptValueCallback(IPC::DataReference const&, bool, WebCore::ExceptionDetails const&, WebKit::CallbackID) + 296
    frame #5: 0x00007fff2d3d43b4 WebKit`void IPC::handleMessage<Messages::WebPageProxy::ScriptValueCallback, WebKit::WebPageProxy, void (WebKit::WebPageProxy::*)(IPC::DataReference const&, bool, WebCore::ExceptionDetails const&, WebKit::CallbackID)>(IPC::Decoder&, WebKit::WebPageProxy*, void (WebKit::WebPageProxy::*)(IPC::DataReference const&, bool, WebCore::ExceptionDetails const&, WebKit::CallbackID)) + 100
    frame #6: 0x00007fff2cf5964e WebKit`IPC::MessageReceiverMap::dispatchMessage(IPC::Connection&, IPC::Decoder&) + 114
    frame #7: 0x00007fff2d1a3ea8 WebKit`WebKit::WebProcessProxy::didReceiveMessage(IPC::Connection&, IPC::Decoder&) + 24
    frame #8: 0x00007fff2cf44cf2 WebKit`IPC::Connection::dispatchMessage(std::__1::unique_ptr<IPC::Decoder, std::__1::default_delete<IPC::Decoder> >) + 158
    frame #9: 0x00007fff2cf47a44 WebKit`IPC::Connection::dispatchIncomingMessages() + 408
    frame #10: 0x00007fff26881d74 JavaScriptCore`WTF::RunLoop::performWork() + 228
    frame #11: 0x00007fff26882002 JavaScriptCore`WTF::RunLoop::performWork(void*) + 34
    frame #12: 0x00007fff23bb2221 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
    frame #13: 0x00007fff23bb214c CoreFoundation`__CFRunLoopDoSource0 + 76
    frame #14: 0x00007fff23bb1924 CoreFoundation`__CFRunLoopDoSources0 + 180
    frame #15: 0x00007fff23bac62f CoreFoundation`__CFRunLoopRun + 1263
    frame #16: 0x00007fff23babe16 CoreFoundation`CFRunLoopRunSpecific + 438
    frame #17: 0x00007fff38438bb0 GraphicsServices`GSEventRunModal + 65
    frame #18: 0x00007fff4784fb68 UIKitCore`UIApplicationMain + 1621
    frame #19: 0x00000001067a6ce5 mindfulness`main(argc=1, argv=0x00007ffee945cce8) at main.m:20:20
    frame #20: 0x00007fff51a1dc25 libdyld.dylib`start + 1
    frame #21: 0x00007fff51a1dc25 libdyld.dylib`start + 1
(lldb) 

NOTES

We've been able to workaround the issue by adding FirebaseDeepLinkAutomaticRetrievalEnabled to Info.plist

Related: #3945

Thanks !

[morganchen12]

@dmandar looks like this can be fixed by taking a strong reference to self inside the completion handler.

[kfieldi5]

Also hitting this issue.

[morganchen12]

Tentatively adding this to the M61 release, which means the fix will hopefully be out by mid-December.

[rzulkoski]

I'm getting the same crash using DynamicLinks in an iOS App rather than a shared framework. Adding the key FirebaseDeepLinkAutomaticRetrievalEnabled with a value of NO to the Info.plist does seem to fix the issue. I've also noticed that I don't have this issue with the zipped version of 6.13.0, only with the Carthage version.

[paulb777]

Was merged with #4325 and will be released with 6.14.0