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gh-138791: fix crash when visiting a non-consumed timer handler #138789

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gh-138791: fix crash when visiting a non-consumed timer handler #138789

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714274c
fix crash when visiting a non-consumed timer handler
picnixz Sep 11, 2025
3873fd5
add regression test
picnixz Sep 11, 2025
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12 changes: 11 additions & 1 deletion Modules/_tkinter.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2764,7 +2764,14 @@ static int
Tktt_Clear(PyObject *op)
{
TkttObject *self = TkttObject_CAST(op);
Py_CLEAR(self->func);
if (self->token != NULL) {
Tcl_DeleteTimerHandler(self->token);
self->token = NULL;
}
if (self->func != NULL) {
Py_CLEAR(self->func);
Py_DECREF(op); /* See Tktt_New() */
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Again, I'm probably missing something -- why do we have that extra reference in the first place?

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To prevent the result of createtimerhandler() from being collected before the timer fires.

}
return 0;
}

Expand All @@ -2783,6 +2790,9 @@ Tktt_Traverse(PyObject *op, visitproc visit, void *arg)
{
TkttObject *self = TkttObject_CAST(op);
Py_VISIT(Py_TYPE(op));
if (self->token != NULL) {
Py_VISIT(op); /* See Tktt_New() */
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I might be missing something, but won't this just lead to infinite recursion?

}
Py_VISIT(self->func);
return 0;
}
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