Tk Source Code: View Ticket

Ticket UUID:	35e67b8124de90cff3e7f54d4407ebb6b14e8513
Title:	tk sysnotify crashes after the interpreter which used it was deleted
Type:	Bug	Version:	9.0.5, trunk
Submitter:	serhiy.storchaka	Created on:	2026-09-18 16:14:34
Subsystem:	-- New Commands	Assigned To:	jan.nijtmans
Priority:	5 Medium	Severity:	Severe
Status:	Pending	Last Modified:	2026-10-08 17:18:38
Resolution:	Fixed	Closed By:	nobody
		Closed on:
Description:	On X11 with libnotify, `tk sysnotify` crashes (9.0.5) or hangs (trunk) when it is called in a new interpreter after the last interpreter which used it was deleted: `foreach name {i j} { interp create $name $name eval {package require Tk; tk sysnotify "Tk test" "test notification"} interp delete $name }` `(tclsh9.0): GLib-GObject-CRITICAL **: cannot register existing type 'NotifyNotification' ... Segmentation fault (core dumped)` `SysNotifyDeleteCmd()` in `unix/tkUnixSysNotify.c` unloads libnotify when the last interpreter is deleted. But libnotify registers GObject types, which cannot be unregistered, so loading it again fails: `notify_notification_new()` returns NULL and `notify_notification_show()` crashes. The fix on branch [sysnotify-no-unload] keeps libnotify loaded for the lifetime of the process; only `notify_uninit()` is called when the last interpreter is deleted. Found by Python's tkinter test suite: https://github.com/python/cpython/pull/157760
User Comments:	serhiy.storchaka added on 2026-10-08 17:18:38: The test was wrong, not the fix. The child interpreters loaded Tk with `package require Tk`, which only works if Tk is installed, and the test assumed that libnotify is loaded, which is not the case without libnotify; on Windows and macOS `tk sysnotify` does not use libnotify at all. Branch sysnotify-test-libnotify loads Tk in the child interpreters as in the main one, and runs the test only on X11 with libnotify loaded (constraint `libnotify` instead of `unix knownBug`). It passes with the fix on X11 and is skipped on Windows; without the fix the test hangs. Not tested on macOS. jan.nijtmans added on 2026-10-08 16:12:52: Merged to [daa6f8f5ec296052\|trunk] and core-9-0-branch Keeping 'Pending' because of the failing testcase jan.nijtmans added on 2026-10-08 16:10:32: I'm seeing the new testcase for this ticket failing on macOS and x11: ==== sysnotify-3 libnotify is not unloaded when the last interpreter which used it is deleted - bug 35e67b8124 FAILED ==== Contents of test case: exec [interpreter] <$script ---- Test generated error; Return code was: 1 ---- Return code should have been one of: 0 2 ---- errorInfo: ok can't delete "::tk::sysnotify::_sysnotify": command doesn't exist can't find package Tk while executing "exec [interpreter] <$script" ("uplevel" body line 2) invoked from within "uplevel 1 $script" ---- errorCode: NONE ==== sysnotify-3 FAILED For now, disabling this testcase