ttk: fix LabeledScale and OptionMenu destroy() method (#3025) (#3030)

vstinner · web-flow · commit 33460fa7e0bd · 2017-08-09T10:48:11.000+02:00
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. (cherry picked from commit cd7e9c1)
diff --git 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):
@@ -1647,5 +1648,8 @@ 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
@@ -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.
