https://github.com/python/cpython/commit/c8047891c75bda51fc773bc289f3cdf50d224b3d commit: c8047891c75bda51fc773bc289f3cdf50d224b3d branch: 3.14 author: Miss Islington (bot) <[email protected]> committer: serhiy-storchaka <[email protected]> date: 2026-07-05T11:14:52Z summary:
[3.14] gh-123193: Document tkinter Variable lifetime (GH-152625) (GH-153099) A Tk variable wrapper unsets its Tcl variable when garbage collected, so a reference must be kept while a widget uses it. Otherwise Tk recreates the Tcl variable but never unsets it again, leaking it. (cherry picked from commit 820b6ca22d72482e2e68dd738cc370535c83655e) Co-authored-by: Serhiy Storchaka <[email protected]> Co-authored-by: Claude Opus 4.8 <[email protected]> files: M Doc/library/tkinter.rst diff --git a/Doc/library/tkinter.rst b/Doc/library/tkinter.rst index d23005ebd8af05..0b66296641e211 100644 --- a/Doc/library/tkinter.rst +++ b/Doc/library/tkinter.rst @@ -658,6 +658,9 @@ method on it, and to change its value you call the :meth:`!set` method. If you follow this protocol, the widget will always track the value of the variable, with no further intervention on your part. +Keep a reference to the variable for as long as a widget uses it, for example +by storing it as an attribute (see :class:`Variable`). + For example:: import tkinter as tk @@ -5658,6 +5661,14 @@ Variable classes :class:`StringVar`, :class:`IntVar`, :class:`DoubleVar` or :class:`BooleanVar` -- rather than :class:`!Variable` directly. + .. note:: + + When a :class:`!Variable` is garbage collected, its Tcl variable is unset. + Keep a reference to it for as long as a widget is linked to it, for example + by storing it as an attribute rather than in a local variable. + Otherwise Tk recreates the Tcl variable to keep the widget working, but it + is never unset again, leaking one Tcl variable per dropped wrapper. + .. versionchanged:: 3.10 Two variables now compare equal (``==``) only when they have the same name, are of the same class, and belong to the same Tcl interpreter. _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
