[Python-checkins] ttk: fix LabeledScale and OptionMenu destroy() method (#3025)

[Victor Stinner]

https://github.com/python/cpython/commit/cd7e9c1b67d3d07ee03e0a79af2791c19031cecb
commit: cd7e9c1b67d3d07ee03e0a79af2791c19031cecb
branch: master
author: Victor Stinner <victor.stinner at gmail.com>
committer: GitHub <noreply at github.com>
date: 2017-08-08T19:41:21+02:00
summary:

ttk: fix LabeledScale and OptionMenu destroy() method (#3025)

bpo-31135: Call the parent destroy() method even if the used
attribute doesn't exist.

The LabeledScale.destroy() method now also explicitly clears label
and scale attributes to help the garbage collector to destroy all
widgets.

files:
A Misc/NEWS.d/next/Library/2017-08-08-14-44-37.bpo-31135.HH94xR.rst
M Lib/tkinter/ttk.py

diff --git a/Lib/tkinter/ttk.py b/Lib/tkinter/ttk.py
index 3ecc004f0e0..e1a965e8dff 100644
--- a/Lib/tkinter/ttk.py
+++ b/Lib/tkinter/ttk.py
@@ -1543,11 +1543,12 @@ def destroy(self):
         try:
             self._variable.trace_vdelete('w', self.__tracecb)
         except AttributeError:
-            # widget has been destroyed already
             pass
         else:
             del self._variable
-            Frame.destroy(self)
+        super().destroy()
+        self.label = None
+        self.scale = None
 
 
     def _adjust(self, *args):
@@ -1644,5 +1645,8 @@ def set_menu(self, default=None, *values):
 
     def destroy(self):
         """Destroy this widget and its associated variable."""
-        del self._variable
-        Menubutton.destroy(self)
+        try:
+            del self._variable
+        except AttributeError:
+            pass
+        super().destroy()
diff --git a/Misc/NEWS.d/next/Library/2017-08-08-14-44-37.bpo-31135.HH94xR.rst b/Misc/NEWS.d/next/Library/2017-08-08-14-44-37.bpo-31135.HH94xR.rst
new file mode 100644
index 00000000000..60068fb648f
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2017-08-08-14-44-37.bpo-31135.HH94xR.rst
@@ -0,0 +1,4 @@
+ttk: fix the destroy() method of LabeledScale and OptionMenu classes.
+Call the parent destroy() method even if the used attribute doesn't
+exist. The LabeledScale.destroy() method now also explicitly clears label and
+scale attributes to help the garbage collector to destroy all widgets.