Ios 10:"如果我们在真正的 pre-commit 句柄中，由于 CA 的限制，我们实际上不能添加任何新的围栏。"

Question

I sometimes get this message in the logs of Xcode 8b3 when running my app, everything seems to work, but I'd like to know where this comes from. Google did not help at all.

转载于:https://stackoverflow.com/questions/38458170/ios-10-app-if-were-in-the-real-pre-commit-handler-we-cant-actually-add-any

Answer 1

It comes from +[UIWindow _synchronizeDrawingAcrossProcessesOverPort:withPreCommitHandler:] via os_log API. It doesn't depend from another components/frameworks that you are using(only from UIKit) - it reproduces in clean single view application project on changing interface orientation.

This method consists from 2 parts:

1. adding passed precommit handler to list of handlers;
2. do some work, that depends on current finite state machine state.

When second part fails (looks like prohibited transition), it prints message above to error log. However, I think that this problem is not fatal: there are 2 additional assert cases in this method, that will lead to crash in debug.

Seems that radar is the best we can do.