Fix #2156977: Use frozenset as the base for DBAPISet. Only tested for

Python 2.5.

MySQLdb/MySQLdb/__init__.py

@@ -31,24 +31,19 @@ from MySQLdb.constants import FIELD_TYPE
 from MySQLdb.times import Date, Time, Timestamp, \
     DateFromTicks, TimeFromTicks, TimestampFromTicks
 
-from sets import ImmutableSet
-class DBAPISet(ImmutableSet):
+try:
+    frozenset
+except NameError:
+    from sets import ImmutableSet as frozenset
+
+class DBAPISet(frozenset):
 
     """A special type of set for which A == x is true if A is a
     DBAPISet and x is a member of that set."""
 
-    def __ne__(self, other):
-        from sets import BaseSet
-        if isinstance(other, BaseSet):
-            return super(DBAPISet.self).__ne__(self, other)
-        else:
-            return other not in self
-
     def __eq__(self, other):
-        from sets import BaseSet
-        if isinstance(other, BaseSet):
-            return super(DBAPISet, self).__eq__(self, other)
-        else:
+        if isinstance(other, DBAPISet):
+            return not self.difference(other)
         return other in self
 
 
@@ -65,6 +60,18 @@ TIMESTAMP = DBAPISet([FIELD_TYPE.TIMESTAMP, FIELD_TYPE.DATETIME])
 DATETIME  = TIMESTAMP
 ROWID     = DBAPISet()
 
+def test_DBAPISet_set_equality():
+    assert STRING == STRING
+
+def test_DBAPISet_set_inequality():
+    assert STRING != NUMBER
+
+def test_DBAPISet_set_equality_membership():
+    assert FIELD_TYPE.VAR_STRING == STRING
+
+def test_DBAPISet_set_inequality_membership():
+    assert FIELD_TYPE.DATE != STRING
+
 def Binary(x):
     return str(x)