Issue #19145: Fix handling of negative values for a "times" keyword argument to itertools.repeat()>

rhettinger · rhettinger · commit 97d3555029b0 · 2014-06-24T21:36:58.000-07:00
(Patch contributed by Vajrasky Kok.)
diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py
@@ -967,6 +967,12 @@ def test_repeat(self):
         self.assertEqual(take(2, copy.deepcopy(c)), list('a' * 2))
         self.pickletest(repeat(object='a', times=10))
 
+    def test_repeat_with_negative_times(self):
+        self.assertEqual(repr(repeat('a', -1)), "repeat('a', 0)")
+        self.assertEqual(repr(repeat('a', -2)), "repeat('a', 0)")
+        self.assertEqual(repr(repeat('a', times=-1)), "repeat('a', 0)")
+        self.assertEqual(repr(repeat('a', times=-2)), "repeat('a', 0)")
+
     def test_map(self):
         self.assertEqual(list(map(operator.pow, range(3), range(1,7))),
                          [0**1, 1**2, 2**3])
@@ -1741,8 +1747,15 @@ class LengthTransparency(unittest.TestCase):
 
     def test_repeat(self):
         self.assertEqual(operator.length_hint(repeat(None, 50)), 50)
+        self.assertEqual(operator.length_hint(repeat(None, 0)), 0)
         self.assertEqual(operator.length_hint(repeat(None), 12), 12)
 
+    def test_repeat_with_negative_times(self):
+        self.assertEqual(operator.length_hint(repeat(None, -1)), 0)
+        self.assertEqual(operator.length_hint(repeat(None, -2)), 0)
+        self.assertEqual(operator.length_hint(repeat(None, times=-1)), 0)
+        self.assertEqual(operator.length_hint(repeat(None, times=-2)), 0)
+
 class RegressionTests(unittest.TestCase):
 
     def test_sf_793826(self):
diff --git a/Misc/ACKS b/Misc/ACKS
@@ -1388,6 +1388,7 @@ Norman Vine
 Pauli Virtanen
 Frank Visser
 Johannes Vogel
+Vajrasky Kok
 Alex Volkov
 Martijn Vries
 Sjoerd de Vries
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -31,6 +31,10 @@ Library
 
 - Issue #21832:  Require named tuple inputs to be exact strings.
 
+- Issue #19145:  The times argument for itertools.repeat now handles
+  negative values the same way for keyword arguments as it does for
+  positional arguments.
+
 - Issue #21812: turtle.shapetransform did not tranform the turtle on the
   first call.  (Issue identified and fixed by Lita Cho.)
 
diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
@@ -4109,14 +4109,17 @@ repeat_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 {
     repeatobject *ro;
     PyObject *element;
-    Py_ssize_t cnt = -1;
+    Py_ssize_t cnt = -1, n_kwds = 0;
     static char *kwargs[] = {"object", "times", NULL};
 
     if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|n:repeat", kwargs,
                                      &element, &cnt))
         return NULL;
 
-    if (PyTuple_Size(args) == 2 && cnt < 0)
+    if (kwds != NULL)
+        n_kwds = PyDict_Size(kwds);
+    /* Does user supply times argument? */
+    if ((PyTuple_Size(args) + n_kwds == 2) && cnt < 0)
         cnt = 0;
 
     ro = (repeatobject *)type->tp_alloc(type, 0);
