Updater crashing on 10.13 if no updates available.

[colincameron]

I'm using the latest Sparkle through Cocoapods, and when I check for updates on a Mac running 10.13.6, the "Checking for updates" window appears, then after a moment, the application crashes with the following error:

Crashing on exception: -[NSAlert runModal] may not be invoked inside of transaction begin/commit pair, or inside of transaction commit (usually this means it was invoked inside of a view's -drawRect: method.)

Here's the relevant part of the backtrace:

Application Specific Backtrace 1:
0   CoreFoundation                      0x00007fff5568b59b __exceptionPreprocess + 171
1   libobjc.A.dylib                     0x00007fff7c9af942 objc_exception_throw + 48
2   CoreFoundation                      0x00007fff5571b935 +[NSException raise:format:] + 197
3   AppKit                              0x00007fff5345c431 _NSRunModal + 484
4   AppKit                              0x00007fff52e3b67d -[NSAlert runModal] + 240
5   Sparkle                             0x000000010e94b64d -[SUUIBasedUpdateDriver showAlert:] + 436
6   Sparkle                             0x000000010e9493d5 -[SUUIBasedUpdateDriver didNotFindUpdate] + 1353

This only happens when there are no updates available. If there is an update, the "Update Available" window appears and I can download the update successfully.

I don't see the crash on 10.14.

[kornelski]

I think we've already fixed that bug. Are you using the latest version of Sparkle?

[colincameron]

I'm on 1.21

[kornelski]

Oh wait, that's not about the main thread. It's about transaction. In that case that's very surprising, because we're not using low-level UI stuff like drawRect. The callback is delayed using performSelectorOnMainThread, so at that point there shouldn't be anything else happening there.