freecad: crash on STL export

[lukeduck321]

Nixpkgs version

Please select a version.

Describe the bug

Screencast.From.2026-05-15.00-51-47.webm

whenever trying to export an STL the entire freccad app locks up and crashes

Steps to reproduce

freecad is defined in my nixos config in environment.systempackages
im launching the app through the desktop icon
issue happens on both a intel i5 nvidia 1650 and a thinkpad e14 gen7

Expected behaviour

it should export an STL and remain open

Screenshots

No response

Relevant log output

Additional context

No response

System metadata

• system: "x86_64-linux"
• host os: Linux 6.12.85, NixOS, 25.11 (Xantusia), 25.11.10470.0c88e1f2bdb9
• multi-user?: yes
• sandbox: yes
• version: nix-env (Nix) 2.31.5
• nixpkgs: /nix/store/ir5c6k27xzwxip8byx2hpy9bvv26ns1w-nixos-25.11.10470.0c88e1f2bdb9/nixos

Notify maintainers

---

Note for maintainers: Please tag this issue in your pull request description. (i.e. Resolves #ISSUE.)

I assert that this issue is relevant for Nixpkgs

• I assert that this is a bug and not a support request.
• I assert that this is not a duplicate of an existing issue.
• I assert that I have read the NixOS Code of Conduct and agree to abide by it.

Is this issue important to you?

Add a 👍 reaction to issues you find important.

[dmkhitaryan]

Seeing as you are on GNOME, I highly suspect this is due to an issue plaguing Qt-based applications on GTK-powered systems.
Can you check if this still results in a failure?
XDG_DATA_DIRS="$(realpath /run/current-system/sw/share/gsettings-schemas/gtk+3-*/):$XDG_DATA_DIRS" freecad

[lukeduck321]

the command stops the crashing, it also stops the crashing for #519574 (comment)

[dmkhitaryan]

It is as suspected, there is a fair few Qt packages with this issue, trying to invoke FileChooser, ColorPicker etc. via GTK.
Until something like #507455 gets merged as a comprehensive fix, packages have to be individually wrapped. In the meantime, you can extend XDG_DATA_DIRS as such:

environment.extraInit = ''
  export XDG_DATA_DIRS="$XDG_DATA_DIRS:${pkgs.gtk3}/share/gsettings-schemas/${pkgs.gtk3.name}"
'';

This workaround applies to any other Qt application that would otherwise crash on GNOME/etc.