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)
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index 0b43905..19af6f7 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -1934,40 +1934,43 @@
int outlen = len;
if (func == Py_None) {
- /* No character is ever false -- share input string
- * (if it's not a subclass) */
- if (PyString_CheckExact(strobj))
+ /* If it's a real string we can return the original,
+ * as no character is ever false and __getitem__
+ * does return this character. If it's a subclass
+ * we must go through the __getitem__ loop */
+ if (PyString_CheckExact(strobj)) {
Py_INCREF(strobj);
- else
- strobj = PyString_FromStringAndSize(
- PyString_AS_STRING(strobj),
- len
- );
- return strobj;
+ return strobj;
+ }
}
if ((result = PyString_FromStringAndSize(NULL, len)) == NULL)
return NULL;
for (i = j = 0; i < len; ++i) {
- PyObject *item, *arg, *good;
+ PyObject *item;
int ok;
item = (*strobj->ob_type->tp_as_sequence->sq_item)(strobj, i);
if (item == NULL)
goto Fail_1;
- arg = Py_BuildValue("(O)", item);
- if (arg == NULL) {
- Py_DECREF(item);
- goto Fail_1;
+ if (func==Py_None) {
+ ok = 1;
+ } else {
+ PyObject *arg, *good;
+ arg = Py_BuildValue("(O)", item);
+ if (arg == NULL) {
+ Py_DECREF(item);
+ goto Fail_1;
+ }
+ good = PyEval_CallObject(func, arg);
+ Py_DECREF(arg);
+ if (good == NULL) {
+ Py_DECREF(item);
+ goto Fail_1;
+ }
+ ok = PyObject_IsTrue(good);
+ Py_DECREF(good);
}
- good = PyEval_CallObject(func, arg);
- Py_DECREF(arg);
- if (good == NULL) {
- Py_DECREF(item);
- goto Fail_1;
- }
- ok = PyObject_IsTrue(good);
- Py_DECREF(good);
if (ok) {
int reslen;
if (!PyString_Check(item)) {
@@ -2026,16 +2029,14 @@
int outlen = len;
if (func == Py_None) {
- /* No character is ever false -- share input string
- * (it if's not a subclass) */
- if (PyUnicode_CheckExact(strobj))
+ /* If it's a real string we can return the original,
+ * as no character is ever false and __getitem__
+ * does return this character. If it's a subclass
+ * we must go through the __getitem__ loop */
+ if (PyUnicode_CheckExact(strobj)) {
Py_INCREF(strobj);
- else
- strobj = PyUnicode_FromUnicode(
- PyUnicode_AS_UNICODE(strobj),
- len
- );
- return strobj;
+ return strobj;
+ }
}
if ((result = PyUnicode_FromUnicode(NULL, len)) == NULL)
return NULL;
@@ -2047,19 +2048,23 @@
item = (*strobj->ob_type->tp_as_sequence->sq_item)(strobj, i);
if (item == NULL)
goto Fail_1;
- arg = Py_BuildValue("(O)", item);
- if (arg == NULL) {
- Py_DECREF(item);
- goto Fail_1;
+ if (func == Py_None) {
+ ok = 1;
+ } else {
+ arg = Py_BuildValue("(O)", item);
+ if (arg == NULL) {
+ Py_DECREF(item);
+ goto Fail_1;
+ }
+ good = PyEval_CallObject(func, arg);
+ Py_DECREF(arg);
+ if (good == NULL) {
+ Py_DECREF(item);
+ goto Fail_1;
+ }
+ ok = PyObject_IsTrue(good);
+ Py_DECREF(good);
}
- good = PyEval_CallObject(func, arg);
- Py_DECREF(arg);
- if (good == NULL) {
- Py_DECREF(item);
- goto Fail_1;
- }
- ok = PyObject_IsTrue(good);
- Py_DECREF(good);
if (ok) {
int reslen;
if (!PyUnicode_Check(item)) {