matplotlib is missing GSettings

[rnhmjoj]

Issue description

When opening the file picker of a matplotlib (gtk3 backend) window the process crashes with this error:
GLib-GIO-ERROR **: No GSettings schemas are installed on the system
I think it needs wrapGAppsHook but I'm not really sure how that works.

Steps to reproduce

$ nix-shell -p 'pythonPackages.matplotlib.override {enableGtk3=true;}' --run 'python -c "import matplotlib.pyplot as plt; plt.plot([1,2,3],[4,5,6]); plt.show()"'

Technical details

NixOS version: 17.09pre106117.c90998d5cf

[rnhmjoj]

Reading #24880 I tried adding to the buildInputs wrapGAppsHook and gsettings_desktop_schemas but it didn't help. Anyone knows how to fix it?

[mmahut]

Any news on this issue?

[rnhmjoj]

Nothing new: It's still happening. Also the package probably has to be wrapped for #65399 .
I have no idea how to to do that on a python library, though.

[doronbehar]

I've just solved this error in an end user application - #84449 The solution is to use wrapGAppsHook which adds something like this to the wrapper:

export XDG_DATA_DIRS='/nix/store/nwksqszw0dakmizrrlql9pamcf39vnxg-gtk+3-3.24.14/share/gsettings-schemas/gtk+3-3.24.14:/nix/store/slmsmbyfgf1rqj9rp6s1y33cqaz8q203-gsettings-desktop-schemas-3.34.0/share/gsettings-schemas/gsettings-desktop-schemas-3.34.0:/nix/store/nwksqszw0dakmizrrlql9pamcf39vnxg-gtk+3-3.24.14/share/gsettings-schemas/gtk+3-3.24.14:/nix/store/slmsmbyfgf1rqj9rp6s1y33cqaz8q203-gsettings-desktop-schemas-3.34.0/share/gsettings-schemas/gsettings-desktop-schemas-3.34.0'${XDG_DATA_DIRS:+':'}$XDG_DATA_DIRS
export XDG_DATA_DIRS='/nix/store/92p57svcsqgwa5fgb8z9qg7m7r66nx7a-guvcview-2.0.6/share'${XDG_DATA_DIRS:+':'}$XDG_DATA_DIRS

To solve this issue in the context of using matplotlib is somewhat challenging because matplotlib is a library - what exactly would we wrap? #83321 is exactly what we need.

[rnhmjoj]

@doronbehar Sadly there is no way, yet. The situation will hopefully change once structured attributes are enabled in nixpkgs and declarative wrappers are implemented. See this issue #72074.

what exactly would we wrap? #83321 is exactly what we need.

Yes, I tried implementing a temporary solution with #83321 because this will take a while before it's usable. It needs some feedback and a lot of testing but it should be working.

[stale]

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[doronbehar]

Still an issue.

…

On Oct 4 2020, at 7:25 pm, stale[bot] ***@***.***> wrote: Hello, I'm a bot and I thank you in the name of the community for opening this issue. To help our human contributors focus on the most-relevant reports, I check up on old issues to see if they're still relevant. This issue has had no activity for 180 days, and so I marked it as stale, but you can rest assured it will never be closed by a non-human. The community would appreciate your effort in checking if the issue is still valid. If it isn't, please close it. If the issue persists, and you'd like to remove the stale label, you simply need to leave a comment. Your comment can be as simple as "still important to me". If you'd like it to get more attention, you can ask for help by searching for maintainers and people that previously touched related code and @ mention them in a comment. You can use Git blame (https://git-scm.com/docs/git-blame) or GitHub's web interface (https://docs.github.com/en/github/managing-files-in-a-repository/tracking-changes-in-a-file) on the relevant files to find them. Lastly, you can always ask for help at our Discourse Forum (https://discourse.nixos.org/) or at #nixos' IRC channel (https://webchat.freenode.net/#nixos). — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub (#25351 (comment)), or unsubscribe (https://github.com/notifications/unsubscribe-auth/ACT5IM2JBIHEXHRFMHH5ZILSJCOWRANCNFSM4DJSM7HA).

[stale]

I marked this as stale due to inactivity. → More info

[rnhmjoj]

Still an issue.

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/jupyter-breaks-matplotlib/15468/2

[stale]

I marked this as stale due to inactivity. → More info

[rnhmjoj]

Still an issue, sadly.

[charmoniumQ]

Is this blocked by RFC 0075?

[rnhmjoj]

Not really, it's possible to fix these issues without a unified wrapping mechanism. See #102949 (comment)

[Artturin]

some patching to make XDG_DATA_DIRS contain schemas before https://github.com/matplotlib/matplotlib/blob/a861b8af82cc4618e0a631e5eac5b4030b3f04a1/lib/matplotlib/backends/backend_gtk3.py#L340 could help

[jtojnar]

I think the simplest solution would be hardcoding the schema path in GTK itself. We now have semi-automated patch generating tooling (see evolution-data-server package for an example), I just have not gotten around to applying it to GTK yet.

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/error-when-trying-to-use-pyqt5-backend-of-matplotlib/46065/4