gh-60203: Revert changes in cycle.__setstate__ (#99982)

In case if only True/False be supported as boolean arguments in future,
we should continue to support 1/0 here.

Lib/test/test_itertools.py

@@ -675,6 +675,7 @@ class TestBasicOps(unittest.TestCase):
         self.assertRaises(TypeError, cycle, 5)
         self.assertEqual(list(islice(cycle(gen3()),10)), [0,1,2,0,1,2,0,1,2,0])
 
+    def test_cycle_copy_pickle(self):
         # check copy, deepcopy, pickle
         c = cycle('abc')
         self.assertEqual(next(c), 'a')
@@ -710,6 +711,37 @@ class TestBasicOps(unittest.TestCase):
             d = pickle.loads(p)                  # rebuild the cycle object
             self.assertEqual(take(20, d), list('cdeabcdeabcdeabcdeab'))
 
+    def test_cycle_unpickle_compat(self):
+        testcases = [
+            b'citertools\ncycle\n(c__builtin__\niter\n((lI1\naI2\naI3\natRI1\nbtR((lI1\naI0\ntb.',
+            b'citertools\ncycle\n(c__builtin__\niter\n(](K\x01K\x02K\x03etRK\x01btR(]K\x01aK\x00tb.',
+            b'\x80\x02citertools\ncycle\nc__builtin__\niter\n](K\x01K\x02K\x03e\x85RK\x01b\x85R]K\x01aK\x00\x86b.',
+            b'\x80\x03citertools\ncycle\ncbuiltins\niter\n](K\x01K\x02K\x03e\x85RK\x01b\x85R]K\x01aK\x00\x86b.',
+            b'\x80\x04\x95=\x00\x00\x00\x00\x00\x00\x00\x8c\titertools\x8c\x05cycle\x93\x8c\x08builtins\x8c\x04iter\x93](K\x01K\x02K\x03e\x85RK\x01b\x85R]K\x01aK\x00\x86b.',
+
+            b'citertools\ncycle\n(c__builtin__\niter\n((lp0\nI1\naI2\naI3\natRI1\nbtR(g0\nI1\ntb.',
+            b'citertools\ncycle\n(c__builtin__\niter\n(]q\x00(K\x01K\x02K\x03etRK\x01btR(h\x00K\x01tb.',
+            b'\x80\x02citertools\ncycle\nc__builtin__\niter\n]q\x00(K\x01K\x02K\x03e\x85RK\x01b\x85Rh\x00K\x01\x86b.',
+            b'\x80\x03citertools\ncycle\ncbuiltins\niter\n]q\x00(K\x01K\x02K\x03e\x85RK\x01b\x85Rh\x00K\x01\x86b.',
+            b'\x80\x04\x95<\x00\x00\x00\x00\x00\x00\x00\x8c\titertools\x8c\x05cycle\x93\x8c\x08builtins\x8c\x04iter\x93]\x94(K\x01K\x02K\x03e\x85RK\x01b\x85Rh\x00K\x01\x86b.',
+
+            b'citertools\ncycle\n(c__builtin__\niter\n((lI1\naI2\naI3\natRI1\nbtR((lI1\naI00\ntb.',
+            b'citertools\ncycle\n(c__builtin__\niter\n(](K\x01K\x02K\x03etRK\x01btR(]K\x01aI00\ntb.',
+            b'\x80\x02citertools\ncycle\nc__builtin__\niter\n](K\x01K\x02K\x03e\x85RK\x01b\x85R]K\x01a\x89\x86b.',
+            b'\x80\x03citertools\ncycle\ncbuiltins\niter\n](K\x01K\x02K\x03e\x85RK\x01b\x85R]K\x01a\x89\x86b.',
+            b'\x80\x04\x95<\x00\x00\x00\x00\x00\x00\x00\x8c\titertools\x8c\x05cycle\x93\x8c\x08builtins\x8c\x04iter\x93](K\x01K\x02K\x03e\x85RK\x01b\x85R]K\x01a\x89\x86b.',
+
+            b'citertools\ncycle\n(c__builtin__\niter\n((lp0\nI1\naI2\naI3\natRI1\nbtR(g0\nI01\ntb.',
+            b'citertools\ncycle\n(c__builtin__\niter\n(]q\x00(K\x01K\x02K\x03etRK\x01btR(h\x00I01\ntb.',
+            b'\x80\x02citertools\ncycle\nc__builtin__\niter\n]q\x00(K\x01K\x02K\x03e\x85RK\x01b\x85Rh\x00\x88\x86b.',
+            b'\x80\x03citertools\ncycle\ncbuiltins\niter\n]q\x00(K\x01K\x02K\x03e\x85RK\x01b\x85Rh\x00\x88\x86b.',
+            b'\x80\x04\x95;\x00\x00\x00\x00\x00\x00\x00\x8c\titertools\x8c\x05cycle\x93\x8c\x08builtins\x8c\x04iter\x93]\x94(K\x01K\x02K\x03e\x85RK\x01b\x85Rh\x00\x88\x86b.',
+        ]
+        assert len(testcases) == 20
+        for t in testcases:
+            it = pickle.loads(t)
+            self.assertEqual(take(10, it), [2, 3, 1, 2, 3, 1, 2, 3, 1, 2])
+
     def test_cycle_setstate(self):
         # Verify both modes for restoring state
 
@@ -739,6 +771,10 @@ class TestBasicOps(unittest.TestCase):
             c.__setstate__((tuple('defg'), 0))
         take(20, c)
 
+        # The second argument in the setstate tuple must be an int
+        with self.assertRaises(TypeError):
+            cycle('defg').__setstate__((list('abcdefg'), 'x'))
+
         self.assertRaises(TypeError, cycle('').__setstate__, ())
         self.assertRaises(TypeError, cycle('').__setstate__, ([],))
 

Modules/itertoolsmodule.c

@@ -1368,12 +1368,13 @@ cycle_setstate(cycleobject *lz, PyObject *state)
         PyErr_SetString(PyExc_TypeError, "state is not a tuple");
         return NULL;
     }
-    if (!PyArg_ParseTuple(state, "O!p", &PyList_Type, &saved, &firstpass)) {
+    // The second item can be 1/0 in old pickles and True/False in new pickles
+    if (!PyArg_ParseTuple(state, "O!i", &PyList_Type, &saved, &firstpass)) {
         return NULL;
     }
     Py_INCREF(saved);
     Py_XSETREF(lz->saved, saved);
-    lz->firstpass = firstpass;
+    lz->firstpass = firstpass != 0;
     lz->index = 0;
     Py_RETURN_NONE;
 }