BUG : fixes FontProperties memory leak

tacaswell · tacaswell · commit a3b18a2df0d4 · 2014-07-17T22:31:36.000-04:00
According to the data model (https://docs.python.org/2/reference/datamodel.html#object.__hash__) objects that define __hash__ need to define __eq__ or __cmp__. By default, all user defined classes have a __cmp__ which evaluates to False for all other objects. Previously we do not define either __cmp__ or __eq__ on FontProperties, This results in never finding the property cached in the dict, hence the growth in the number of FontProperties (and I assume the stuff in them). By adding __eq__ and __ne__ we complete the data model and adding FontProperties to dictionaries should work as expected. This was not a problem before, but in matplotlib#3077 the caching key was changed from hash(prop) -> prop. Closes matplotlib#3264
diff --git a/lib/matplotlib/font_manager.py b/lib/matplotlib/font_manager.py
@@ -707,6 +707,12 @@ def __hash__(self):
              self.get_file())
         return hash(l)
 
+    def __eq__(self, other):
+        return hash(self) == hash(other)
+
+    def __ne__(self, other):
+        return hash(self) != hash(other)
+
     def __str__(self):
         return self.get_fontconfig_pattern()
 
