Fix pyplot.axes(ax) when ax is in other figure.

pavoljuhas · pavoljuhas · commit 37d7f1f8a25b · 2017-02-07T18:56:09.000-05:00
Avoid crash when `ax` belongs to some other than the current figure.
Make the `ax` owner the current figure instead.
diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
@@ -875,7 +875,8 @@ def axes(*args, **kwargs):
       color for the axis, default white.
 
     - ``axes(h)`` where *h* is an axes instance makes *h* the current
-      axis.  An :class:`~matplotlib.axes.Axes` instance is returned.
+      axis and the parent of *h* the current figure.
+      An :class:`~matplotlib.axes.Axes` instance is returned.
 
     =========   ==============   ==============================================
     kwarg       Accepts          Description
@@ -909,7 +910,8 @@ def axes(*args, **kwargs):
     arg = args[0]
 
     if isinstance(arg, Axes):
-        a = gcf().sca(arg)
+        sca(arg)
+        a = arg
     else:
         rect = arg
         a = gcf().add_axes(rect, **kwargs)
