MNT: tweak MovieWriter.saving to be more cautious

tacaswell · tacaswell · commit 437386b35bce · 2016-12-10T21:55:15.000-05:00
- always try to call `finish` even if an exception is raised.
 - return `self` so that

    with writer.saving(...) as mv:
        mv.grab_frame()

   works as expected.
diff --git a/lib/matplotlib/animation.py b/lib/matplotlib/animation.py
@@ -236,8 +236,10 @@ def saving(self, *args, **kw):
         '''
         # This particular sequence is what contextlib.contextmanager wants
         self.setup(*args, **kw)
-        yield
-        self.finish()
+        try:
+            yield self
+        finally:
+            self.finish()
 
     def _run(self):
         # Uses subprocess to call the program for assembling frames into a
