Segmentation fault with any applied Qt stylesheet when switch off from Transform Module

Hi,

On Ubuntu 20.04 if I try to apply Qt stylesheet (for example using SandBox style tester with these two default lines) and switch after that I switch to the Transform module and then switch to any other module I get segmentation fault. This makes Qt stylesheets unusable.

Does this happen only on Ubuntu?

I haven’t figured out why this happens only with Transform module but it seems that something related to applying style during qSlicerModulePanel::removeModule:

Thanks for the report :pray:

We should definitely understand the issue and address the problem.

To help move forward with this, could you:

  • share a small standalone example allowing to reproduce the problem. It could be as simple as a list of steps to follow, and few lines that need to be copied into the python interactor
  • provide some context for reproducing:
    • can it be reproduced using the preview package available from https://download.slicer.org
    • is the issue specific to a build of Slicer (if yes, which version of Qt)

Thank you for reply,

Steps to reproduce:

  1. from extension manager install Sandbox extension;
  2. restart Slicer;
  3. after the restart go to the Modules->Developer Tools->StyleTester and click on Apply to Slicer radiobutton and then click Apply Style pushbutton;
  4. go to the Modules->Transforms (should be fine);
  5. go to any other module (for example Modules->Data) or click Previous modules tool button (here I get segfault)

This can be reproduced on Ubuntu 20.04 with Slicer downloaded from official web-site v4.13.0 built 2022-02-03 or with Slicer manually built with Qt 5.15.2 with GCC 9.3

I just tested that on Windows and it seems that there is no such problem.
But on Ubuntu I get segfault even with the newest Slicer version 2022-03-26

This might be the same thing I ran into with my slicer custom app here: crash when switching out of transforms module · Issue #15 · KitwareMedical/lungair-desktop-application · GitHub

Yes I think we encountered the same crash.
But it is not only about SlicerCAT but I can see this crash in Slicer app.
Did you ran into this on Linux?

Yes, this was also on Ubuntu 20.04

New investigations of that problem are described here.

Appreciate if somebody take a look.