Change filterstring() and filterunicode(): If the
object is not a real str or unicode but an instance
of a subclass, construct the output via looping
over __getitem__. This guarantees that the result
is the same for function==None and function==lambda x:x
This doesn't happen for tuples, because filtertuple()
uses PyTuple_GetItem().
(This was discussed on SF bug #665835).
diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
index 047e93e..9af3233 100644
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -418,26 +418,40 @@
def test_filter_subclasses(self):
# test, that filter() never returns tuple, str or unicode subclasses
+ # and that the result always go's through __getitem__
+ # FIXME: For tuple currently it doesn't go through __getitem__
funcs = (None, lambda x: True)
class tuple2(tuple):
- pass
+ def __getitem__(self, index):
+ return 2*tuple.__getitem__(self, index)
class str2(str):
- pass
+ def __getitem__(self, index):
+ return 2*str.__getitem__(self, index)
inputs = {
- tuple2: [(), (1,2,3)],
- str2: ["", "123"]
+ tuple2: {(): (), (1, 2, 3): (1, 2, 3)}, # FIXME
+ str2: {"": "", "123": "112233"}
}
if have_unicode:
class unicode2(unicode):
- pass
- inputs[unicode2] = [unicode(), unicode("123")]
+ def __getitem__(self, index):
+ return 2*unicode.__getitem__(self, index)
+ inputs[unicode2] = {
+ unicode(): unicode(),
+ unicode("123"): unicode("112233")
+ }
- for func in funcs:
- for (cls, inps) in inputs.iteritems():
- for inp in inps:
- out = filter(func, cls(inp))
- self.assertEqual(inp, out)
- self.assert_(not isinstance(out, cls))
+ for (cls, inps) in inputs.iteritems():
+ for (inp, exp) in inps.iteritems():
+ # make sure the output goes through __getitem__
+ # even if func is None
+ self.assertEqual(
+ filter(funcs[0], cls(inp)),
+ filter(funcs[1], cls(inp))
+ )
+ for func in funcs:
+ outp = filter(func, cls(inp))
+ self.assertEqual(outp, exp)
+ self.assert_(not isinstance(outp, cls))
def test_float(self):
self.assertEqual(float(3.14), 3.14)