Bug 780329 - Part 4: Define CompilerWarning.__cmp__; r=jhammel DONTBUILD (NPOTB)

python/mozbuild/mozbuild/compilation/warnings.py

@@ -71,6 +71,18 @@ class CompilerWarning(dict):
         """Define so this can exist inside a set, etc."""
         return hash(tuple(sorted(self.items())))
 
+    def __cmp__(self, other):
+        if not isinstance(other, CompilerWarning):
+            return -1
+
+        for key in ('filename', 'line', 'column'):
+            x = cmp(self[key], other[key])
+
+            if x != 0:
+                return x
+
+        return 0
+
 
 class WarningsDatabase(object):
     """Holds a collection of warnings.