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Importing idlelib.run deletes tkinter dialog submodules from sys.modules #156896
Description
Bug report
idlelib/run.py scrubs tkinter at import time (bpo-25507, gh-59396):
for mod in ('simpledialog', 'messagebox', 'font', 'dialog', 'filedialog', 'commondialog', 'ttk'):
try:
delattr(tkinter, mod)
del sys.modules['tkinter.' + mod]
except (AttributeError, KeyError):
passtest_run.py does from idlelib import run, so running it evicts tkinter.commondialog from sys.modules. A later import re-executes commondialog, creating a second Dialog class.
The common-dialog tests cache the class at load (from tkinter.commondialog import Dialog) and patch it with swap_attr(Dialog, '_test_callback', ...). After the re-import that cached class is stale, so the patch misses the class the live dialog uses, and test_colorchooser.test_askcolor opens the real modal color chooser and hangs:
./python -m test -uall test_tkinter test_ttk test_idle
It only fails when test_run runs before the dialog test in the same process (not under -j).
Importing a module shouldn't mutate global sys.modules; idlelib.run should do the scrub only when launched as the subprocess main, not at import.
Linked PRs
- gh-156896: Stop scrubbing tkinker submodules upon idlelib.run import #156915
- [3.15] gh-156896: Stop scrubbing tkinter submodules upon idlelib.run import (GH-156915) #156958
- [3.14] gh-156896: Stop scrubbing tkinter submodules upon idlelib.run import (GH-156915) #156959
- [3.13] gh-156896: Stop scrubbing tkinter submodules upon idlelib.run import (GH-156915) #156960
Activity
terryjreedy commentedon Sep 3, 2026
I agree. The purpose is to prevent user code running from IDLE passing when it should fail due to missing tkinter submodule imports. I will add the needed clause to the existing
ifguard.terryjreedy commentedon Sep 4, 2026
Module run is not launched as subprocess main. It is imported with
__import__('idlelib.run'), avoiding binding it in main. (Function run.main is run by appending.run.main()to the import.) So I 'guarded' the scrubbing by wrapping it in a function called at the top of main.gh-156896: Stop scrubbing tkinker submodules upon idlelib.run import (#…
[3.14] gh-156896: Stop scrubbing tkinter submodules upon idlelib.run …
[3.13] gh-156896: Stop scrubbing tkinter submodules upon idlelib.run …
pythongh-156896: Stop scrubbing tkinker submodules upon idlelib.run i…
serhiy-storchaka commentedon Sep 15, 2026
Fixed in main by #156915 and backported to 3.13 (#156960) and 3.14 (#156959). The 3.15 backport #156958 is waiting for the release manager.
[3.15] gh-156896: Stop scrubbing tkinter submodules upon idlelib.run …