Handle FigureManager destroy internaly without pyplot.

lib/matplotlib/_pylab_helpers.py

@@ -124,7 +124,7 @@ def destroy(cls, num):
                 cls._activeQue.append(f)
 
         del cls.figs[num]
-        manager.destroy()
+        manager.destroy()  # Unneeded with MEP27 remove later
         gc.collect(1)
 
     @classmethod

lib/matplotlib/backend_bases.py

@@ -2530,7 +2530,7 @@ def key_press_handler(event, canvas, toolbar=None):
         if isinstance(canvas.manager, FigureManagerBase):  # Using old figman.
             Gcf.destroy_fig(canvas.figure)
         else:
-            canvas.manager._destroy('window_destroy_event')
+            canvas.manager.destroy('window_destroy_event')
 
     if toolbar is not None:
         # home or reset mnemonic  (default key 'h', 'home' and 'r')

lib/matplotlib/backend_managers.py

@@ -78,7 +78,7 @@ def __init__(self, figure, num):
         self._backend = get_backend()
         self._mainloop = self._backend.MainLoop()
         self.window = self._backend.Window('Figure %d' % num)
-        self.window.mpl_connect('window_destroy_event', self._destroy)
+        self.window.mpl_connect('window_destroy_event', self.destroy)
 
         self.canvas = self._backend.FigureCanvas(figure, manager=self)
 
@@ -122,23 +122,29 @@ def key_press(self, event):
         """
         key_press_handler(event, self.canvas, self.canvas.toolbar)
 
-    def _destroy(self, event=None):
-        # Callback from the when the window wants to destroy itself
-        s = 'window_destroy_event'
-        event = FigureManagerEvent(s, self)
-        self._callbacks.process(s, event)
-
     def destroy(self, *args):
-        """Called to destroy this FigureManager, gets called by Gcf through
-        event magic.
+        """Called to destroy this FigureManager.
         """
+
+        # Make sure we run this routine only once for the FigureManager
+        # This ensures the nasty __del__ fix below works.
+        if getattr(self, '_destroying', False):
+            return
+
+        self._destroying = True
         self.canvas.destroy()
         if self.toolbar:
             self.toolbar.destroy()
         self.window.destroy()
 
+        # Fix as for some reason we have extra references to this#
+        # i.e. ``del self._mainloop`` doesn't work
         self._mainloop.__del__()
 
+        s = 'window_destroy_event'
+        event = FigureManagerEvent(s, self)
+        self._callbacks.process(s, event)
+
     def show(self):
         """Shows the figure"""
         self.window.show()

lib/matplotlib/backend_tools.py

@@ -322,7 +322,7 @@ def trigger(self, sender, event, data=None):
         except:
             pass
         else:
-            manager._destroy('window_destroy_event')
+            manager.destroy('window_destroy_event')
 
 
 class ToolEnableAllNavigation(ToolBase):