Fix `AttributeError: module 'gi' has no attribute 'require_version'` #30657

heinrich5991 · 2025-10-17T07:12:10Z

On Arch Linux, automatic backend selection fails when at-spi2-core is installed but
python-gobject is not. Detect this by importing gi.require_version directly.

>>> import matplotlib.pyplot as plt
>>> plt.plot([0, 1], [0, 1])
Traceback (most recent call last):
  File "<python-input-1>", line 1, in <module>
    plt.plot([0, 1], [0, 1])
    ~~~~~~~~^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 3838, in plot
    return gca().plot(
           ~~~^^
  File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 2785, in gca
    return gcf().gca()
           ~~~^^
  File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 1108, in gcf
    return figure()
  File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 1042, in figure
    manager = new_figure_manager(
        num, figsize=figsize, dpi=dpi,
        facecolor=facecolor, edgecolor=edgecolor, frameon=frameon,
        FigureClass=FigureClass, **kwargs)
  File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 551, in new_figure_manager
    _warn_if_gui_out_of_main_thread()
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 528, in _warn_if_gui_out_of_main_thread
    canvas_class = cast(type[FigureCanvasBase], _get_backend_mod().FigureCanvas)
                                                ~~~~~~~~~~~~~~~~^^
  File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 369, in _get_backend_mod
    switch_backend(rcParams._get("backend"))
    ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 411, in switch_backend
    switch_backend(candidate)
    ~~~~~~~~~~~~~~^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 425, in switch_backend
    module = backend_registry.load_backend_module(newbackend)
  File "/usr/lib/python3.13/site-packages/matplotlib/backends/registry.py", line 317, in load_backend_module
    return importlib.import_module(module_name)
           ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/usr/lib/python3.13/importlib/__init__.py", line 88, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 1026, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/usr/lib/python3.13/site-packages/matplotlib/backends/backend_gtk4agg.py", line 4, in <module>
    from . import backend_agg, backend_gtk4
  File "/usr/lib/python3.13/site-packages/matplotlib/backends/backend_gtk4.py", line 19, in <module>
    gi.require_version("Gtk", "4.0")
    ^^^^^^^^^^^^^^^^^^
AttributeError: module 'gi' has no attribute 'require_version'

Fixes #30654.

PR checklist

"closes #0000" is in the body of the PR description to link the related issue
new and changed code is tested
[n/a] Plotting related features are demonstrated in an example
[n/a] New Features and API Changes are noted with a directive and release note
[n/a] Documentation complies with general and docstring guidelines

heinrich5991 · 2025-10-17T07:15:54Z

How can I add tests for this?

@tacaswell I took the liberty and deviated from what I've originally proposed to lower the amount of code that gets executed in a try: […] except AttributeError: […] block, so that fewer exceptions get accidentally silenced. Please let me know if I should PR my originally proposed change instead.

heinrich5991 · 2025-10-17T08:10:28Z

I'm not sure if the ubuntu-24.04-arm test failure is related to my PR. Can someone help me?

rcomer · 2025-10-17T11:01:21Z

That failure is happening on various PRs. Since it's a timeout error, I re-started the job to see if it passes on second attempt.

tacaswell · 2025-10-17T17:04:38Z

lib/matplotlib/backends/backend_gtk3.py

+try:
+    gi.require_version
+except AttributeError as err:
+    raise ImportError("The GTK3 backends require PyGObject") from err


Does the error message above need to be corrected then? I do not fully understand how PyGObject / gobject introspection splits itself up in either and upstream sense or the downstream packaging sense (which I assume different packagers make different choices?).

"No, this is the right error message in both cases" is perfectly good answer, but if we can make this a bit more precise that would be good.

Does the error message above need to be corrected then?

I think it's the correct error as the remediation is (on Arch Linux) to install python-gobject. import gi doesn't fail because other packages populate the /usr/lib/python3.13/site-packages/gi/ path, e.g. with /usr/lib/python3.13/site-packages/gi/overrides/Atspi.py.

This is likely a consequence of Python's new(ish) implicit namespace packages.

tacaswell

On the "does the machinery do what it should" front, 👍

I left one comment making the human facing error message more precise, but approving the PR so if the answer is "this is the best we can do", then we only need one more review.

tacaswell · 2025-10-17T17:11:50Z

This is something where I'm ok with not adding an explicit test. We know that we can get an attribute error raised and have other tests that the machinery that catches the ImportError works correctly. The work to construct a test case with a half-installed pygobject and then maintain it going forward is in my judgement not worth the opportunity cost of spending that effort else where.

WeatherGod · 2025-10-17T18:08:20Z

One little nitpick. Should the ImportError be raised from `None` or `err`?

…

On Fri, Oct 17, 2025 at 1:12 PM Thomas A Caswell ***@***.***> wrote: *tacaswell* left a comment (matplotlib/matplotlib#30657) <#30657 (comment)> This is something where I'm ok with not adding an explicit test. We know that we can get an attribute error raised and have other tests that the machinery that catches the ImportError works correctly. The work to construct a test case with a half-installed pygobject and then maintain it going forward is in my judgement not worth the opportunity cost of spending that effort else where. — Reply to this email directly, view it on GitHub <#30657 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AACHF6AIO5CP3PAFULOUBI33YEPO5AVCNFSM6AAAAACJOKAIIOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTIMJWGQYDCMJXGI> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

heinrich5991 · 2025-10-18T13:05:35Z

One little nitpick. Should the ImportError be raised from None or err?

I'd think from err because the AttributeError is the cause.

heinrich5991 · 2025-10-18T13:07:16Z

I have a different suggestion, maybe we could instead use

from gi import require_version as gi_require_version

Then we don't have to catch the AttributeError.

heinrich5991 · 2025-10-18T14:09:47Z

If you like the other approach, I can squash the commits. :)

tacaswell · 2025-10-20T14:51:32Z

I like the import-as approach better, more lines of change, but simplifies the logic.

On Arch Linux, automatic backend selection fails when [`at-spi2-core`](https://archlinux.org/packages/extra/x86_64/at-spi2-core/files/) is installed but [`python-gobject`](https://archlinux.org/packages/extra/x86_64/python-gobject/files/) is not. Detect this by importign `gi.require_version` directly. ```python >>> import matplotlib.pyplot as plt >>> plt.plot([0, 1], [0, 1]) Traceback (most recent call last): File "<python-input-1>", line 1, in <module> plt.plot([0, 1], [0, 1]) ~~~~~~~~^^^^^^^^^^^^^^^^ File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 3838, in plot return gca().plot( ~~~^^ File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 2785, in gca return gcf().gca() ~~~^^ File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 1108, in gcf return figure() File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 1042, in figure manager = new_figure_manager( num, figsize=figsize, dpi=dpi, facecolor=facecolor, edgecolor=edgecolor, frameon=frameon, FigureClass=FigureClass, **kwargs) File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 551, in new_figure_manager _warn_if_gui_out_of_main_thread() ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^ File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 528, in _warn_if_gui_out_of_main_thread canvas_class = cast(type[FigureCanvasBase], _get_backend_mod().FigureCanvas) ~~~~~~~~~~~~~~~~^^ File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 369, in _get_backend_mod switch_backend(rcParams._get("backend")) ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 411, in switch_backend switch_backend(candidate) ~~~~~~~~~~~~~~^^^^^^^^^^^ File "/usr/lib/python3.13/site-packages/matplotlib/pyplot.py", line 425, in switch_backend module = backend_registry.load_backend_module(newbackend) File "/usr/lib/python3.13/site-packages/matplotlib/backends/registry.py", line 317, in load_backend_module return importlib.import_module(module_name) ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^ File "/usr/lib/python3.13/importlib/__init__.py", line 88, in import_module return _bootstrap._gcd_import(name[level:], package, level) ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "<frozen importlib._bootstrap>", line 1387, in _gcd_import File "<frozen importlib._bootstrap>", line 1360, in _find_and_load File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 935, in _load_unlocked File "<frozen importlib._bootstrap_external>", line 1026, in exec_module File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed File "/usr/lib/python3.13/site-packages/matplotlib/backends/backend_gtk4agg.py", line 4, in <module> from . import backend_agg, backend_gtk4 File "/usr/lib/python3.13/site-packages/matplotlib/backends/backend_gtk4.py", line 19, in <module> gi.require_version("Gtk", "4.0") ^^^^^^^^^^^^^^^^^^ AttributeError: module 'gi' has no attribute 'require_version' ``` Fixes matplotlib#30654.

heinrich5991 · 2025-10-20T15:18:09Z

Squashed the commits.

heinrich5991 · 2025-10-20T15:53:22Z

Could someone retry the failed pipeline? I'm not sure if it's related to this PR, I'd guess "no".

tacaswell

Still approve of simplified version.

tacaswell · 2025-10-20T15:58:24Z

Thanks! This still needs a second reviewer to merge it.

QuLogic · 2025-10-21T07:56:11Z

Thanks @heinrich5991! Congratulations on your first PR to Matplotlib 🎉 We hope to hear from you again.

lumberbot-app · 2025-10-21T07:56:15Z

Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

Checkout backport branch and update it.

git checkout v3.10.x
git pull

Cherry pick the first parent branch of the this PR on top of the older branch:

git cherry-pick -x -m1 ea40d72fb0b5da047ffb02e9d6322531334354ae

You will likely have some merge/cherry-pick conflict here, fix them and commit:

git commit -am "Backport PR #30657: Fix `AttributeError: module 'gi' has no attribute 'require_version'`"

Push to a named branch:

git push YOURFORK v3.10.x:auto-backport-of-pr-30657-on-v3.10.x

Create a PR against branch v3.10.x, I would have named this PR:

"Backport PR #30657 on branch v3.10.x (Fix AttributeError: module 'gi' has no attribute 'require_version')"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the Still Needs Manual Backport label once the PR gets merged.

If these instructions are inaccurate, feel free to suggest an improvement.

… attribute 'require_version'`

…3.10.x Backport PR #30657 on branch v3.10.x (Fix AttributeError: module 'gi' has no attribute 'require_version')

github-actions bot added the GUI: gtk label Oct 17, 2025

heinrich5991 mentioned this pull request Oct 17, 2025

[Bug]: error plotting: AttributeError: module 'gi' has no attribute 'require_version' #30654

Closed

heinrich5991 mentioned this pull request Oct 17, 2025

[MNT]: First contributor workflow fails for first contributors #30658

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tacaswell reviewed Oct 17, 2025

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tacaswell approved these changes Oct 17, 2025

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tacaswell added this to the v3.10.8 milestone Oct 17, 2025

heinrich5991 force-pushed the pr_attributeerror_gi_require_version branch from 7c07889 to 3ecf087 Compare October 20, 2025 15:17

tacaswell approved these changes Oct 20, 2025

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QuLogic approved these changes Oct 21, 2025

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QuLogic merged commit ea40d72 into matplotlib:main Oct 21, 2025
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lumberbot-app bot added the Still Needs Manual Backport label Oct 21, 2025

QuLogic added a commit to QuLogic/matplotlib that referenced this pull request Oct 23, 2025

Backport PR matplotlib#30657: Fix `AttributeError: module 'gi' has no…

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… attribute 'require_version'`

QuLogic removed the Still Needs Manual Backport label Oct 23, 2025

timhoffm added a commit that referenced this pull request Oct 23, 2025

Merge pull request #30675 from QuLogic/auto-backport-of-pr-30657-on-v…

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…3.10.x Backport PR #30657 on branch v3.10.x (Fix AttributeError: module 'gi' has no attribute 'require_version')

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Fix `AttributeError: module 'gi' has no attribute 'require_version'` #30657

Fix `AttributeError: module 'gi' has no attribute 'require_version'` #30657

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