segfault in ~GLSLWaveformWidget when changing skins

[Foss-4]

2.3.0-alpha-pre (build master r7034)
macOS 10.14.6

crash when switching themes.
reproducible: always.

Currently using Tango theme. Switching to any other theme will result in crash (see attached txt).

[ronso0 (ronso0)]

In the report it's a waveform-related thread that's crashing.

could you try another waveform renderer?

Also, can you try to set another skin manually in mixxx.cfg?

[Foss-4 (foss-4)]

Was using RGB (GLSL)

switched to RGB and then changing the interface skin indeed works fine.

[ronso0 (ronso0)]

okay.
can you verify thatit's skin-independent?

If so please change the bug title accordingly (alos IIRC there's already a relatedd bug)

[Foss-4 (foss-4)]

Skin independent indeed. Doesn't matter which skin is currently selected or to which skin user is switching to. Always reproducible when RGB (GLSL) as waveform renderer is selected.

[Foss-4 (foss-4)]

Findings from duplicate report:

Jean-Michaël:
I've tried changing skin on current master (mac mini 2018, 10.14, Qt 5.15 from homebrew) but I don't seem to hit the issue.
I however seem to hit the same backtracewhen quitting Mixxx so that may be related ?
It seems to be due to

GLSLWaveformWidget::~GLSLWaveformWidget() {
    makeCurrent();
}

^ I don't really know Mixxx's architecture, but that seems quite dangerous if the SharedGLContext::getWidget()'s context gets destroyed before the waveform widget - maybe some place in the code should introduce an explicit ordering of child widget deletion in a destructor that guarantees that the waveforms are deleted first, before the main window is closed, instead of relying on Qt's parent-child automatic destruction for this case.

Uwe:
The invocation of makeCurrent() also triggers a crash on Linux when closing Mixxx with Alt+F4:
https://mixxx.zulipchat.com/#narrow/stream/109171-development/topic/shutdown.20crash

https://github.com/mixxxdj/mixxx/pull/2933

[Foss-4 (foss-4)]

Peristing with 2.3.0-beta (build 2.3 r7489)
https://bin.disroot.org/?780c7ff969ce2d12#HA1FUDWQN4tGQPXsK7ivDoy6A2vQV5dftyYQfg2UzRkj

Persisting with 2.4.0-alpha-pre (build master r7459)
https://bin.disroot.org/?8229a565da567327#H7Uq1viXgkey6gyS49YkXyq1ZAGfvBhSugnAs5oquE2X

[Be (be.ing)]

Oh, Bug #1877487 is actually a separate bug from this. This bug was fixed, Bug #1877487 was not.

[Be (be.ing)]

> Peristing with 2.3.0-beta (build 2.3 r7489)
https://bin.disroot.org/?780c7ff969ce2d12#HA1FUDWQN4tGQPXsK7ivDoy6A2vQV5dftyYQfg2UzRkj

That backtrace is the same as Bug #1877487.

[Be (be.ing)]

This bug was fixed in https://github.com/mixxxdj/mixxx/pull/2933

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/9844