Fix crash due to dangling pointer access in developer mode. - Githubissues

mixxxdj / mixxx

Mixxx is Free DJ software that gives you everything you need to perform live mixes.

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Fix crash due to dangling pointer access in developer mode. #13889

Closed daschuer closed 6 days ago

daschuer commented 1 week ago

This fixes a regression #13885 since https://github.com/mixxxdj/mixxx/pull/12094

daschuer commented 1 week ago

Done

JoergAtGithub commented 6 days ago

@daschuer Thank you for jumping in! The fix LGTM and I just tested it on Win11 -> Works as expected!

ronso0 commented 6 days ago

Thanks @daschuer for quick fix! Can confirm it doesn't crash anymore.

However, I want to note that I saw the crash for other event types, too, eg. QChildEvent(ChildRemoved, ..). So, presuming

12094 is for diagnosis only
we can't be sure it happens only for QEvent::DeferredDelete
a crash can cause losing data from the current session
users may run Mixxx with --developer in regular session to have MIDI Through for MIDI4Light

shall we tie to another developer option, eg. a certain log level?

JoergAtGithub commented 5 days ago

However, I want to note that I saw the crash for other event types, too, eg. QChildEvent(ChildRemoved, ..).

Than I see only two options:

Cache the object informantion before calling notify, which will affect the general performance in developer mode
Remove the printout of the target object information and just print the information about the event type

ronso0 commented 4 days ago

implementing #8356 would "fix" it IMO since this eliminates the only reason I know to run Mixxx with --developer in regular sessions