Fix infinite recursion in units with ndarray subclasses.

dopplershift · dopplershift · commit cee4ba990c7e · 2013-11-13T20:57:05.000-06:00
This was partially addressed for masked arrays in #2290. However, this does not work for all ndarray sub-classes, like the quantities package. The fix here is to make sure ravel is actually succeeding in changing the shape of the object. If it doesn't just return what we've got.
diff --git a/lib/matplotlib/units.py b/lib/matplotlib/units.py
@@ -149,7 +149,13 @@ def get_converter(self, x):
                     return converter
             except AttributeError:
                 # not a masked_array
-                converter = self.get_converter(xravel[0])
+                # Make sure we don't recurse forever -- it's possible for
+                # ndarray subclasses to continue to return subclasses and
+                # not ever return a non-subclass for a single element.
+                next_item = xravel[0]
+                if (not isinstance(next_item, np.ndarray) or
+                    next_item.shape != x.shape):
+                    converter = self.get_converter(next_item)
                 return converter
 
         if converter is None and iterable(x):
