[Bug] Deadlock in firebase::auth::IdTokenRefreshThread

[venge-vimeo]

[REQUIRED] Please fill in the following fields:

• Pre-built SDK from the website or open-source from this repo: open-source from this repo
• Firebase C++ SDK version: 11.4.0
• Problematic Firebase Component: auth
• Other Firebase Components in use: database
• Platform you are using the C++ SDK on: Mac, Windows
• Platform you are targeting: desktop

[REQUIRED] Please describe the issue here:

Deadlock in IdTokenRefreshThread which causes the entire app to hang, e.g., Database cannot be safely deleted since it is deadlocked on destruction by waiting IdTokenRefreshThread to finish

1. IdTokenRefreshThread holds refresh_thread->ref_count_mutex_ and auth->auth_data_->future_impl.mutex(). Then it accesses refresh_thread->token_refresh_listener_.GetTokenTimestamp() which has its own mutex

#0	firebase::auth::IdTokenRefreshThread::Initialize(firebase::auth::AuthData*)::$_4::operator()(firebase::auth::IdTokenRefreshThread*) const at /Users/venhe/tmp/Firebase/Firebase/auth/src/desktop/auth_desktop.cc:818
#1	firebase::auth::IdTokenRefreshThread::Initialize(firebase::auth::AuthData*)::$_4::__invoke(firebase::auth::IdTokenRefreshThread*) at /Users/venhe/tmp/Firebase/Firebase/auth/src/desktop/auth_desktop.cc:805

2. Another worker thread fires an event about token change. IdTokenRefreshListener::OnIdTokenChanged locks its own mutex first and then auth->auth_data_->future_impl.mutex()

#0	firebase::auth::IdTokenRefreshListener::OnIdTokenChanged(firebase::auth::Auth*) at /Users/venhe/tmp/Firebase/Firebase/auth/src/desktop/auth_desktop.cc:135
#1	firebase::auth::NotifyIdTokenListeners(firebase::auth::AuthData*) at /Users/venhe/tmp/Firebase/Firebase/auth/src/auth.cc:362
#2	0firebase::auth::AuthenticationResult::SetAsCurrentUser(firebase::auth::AuthData*) const at /Users/venhe/tmp/Firebase/Firebase/auth/src/desktop/authentication_result.cc:64
#3	void firebase::auth::PerformSignInFlow<firebase::auth::VerifyCustomTokenResponse, firebase::auth::AuthResult, firebase::auth::VerifyCustomTokenRequest>(firebase::auth::AuthDataHandle<firebase::auth::AuthResult, firebase::auth::VerifyCustomTokenRequest>*) at /Users/venhe/tmp/Firebase/Firebase/auth/src/desktop/sign_in_flow.h:125

Deadlock happens if IdTokenRefreshThread just about to call GetTokenTimestamp and if IdTokenRefreshListener::OnIdTokenChanged successfully acquired its mutex.

Steps to reproduce:

Hard to reproduce, but happens quite often.

What happened? How can we make the problem occur?

Simulate it, e.g., call IdTokenRefreshListener::OnIdTokenChanged in a loop, and it will definitely deadlock at some point

If you have a downloadable sample project that reproduces the bug you're reporting, you will
likely receive a faster response on your issue.

[awemvfx]

Any update on this?