UI API called from background thread in Swift 4 an

问题:

These are the errors that are currently present in my project after I downloaded the beta version of Xcode 9.

This directly connects to this post. In which similar problem is solved. I had this problem as well originally and fixed it by following the accepted solution. However, that did not fix these other error messages that I am getting.

What is causing these? Are they a problem? How can I prevent them?

回答1:

From your stack trace, it looks like both calls are Firebase related. As such, try upgrading to the latest Firebase version 4.x to see if those go away.

Please see this question if you may need some help when doing so.

Update. Actually, it looks like this is a known issue in Firebase v4 iOS SDK :-(