python · serhiy-storchaka · Mar 20, 2017 · Mar 17, 2017 · Mar 17, 2017
diff --git a/Lib/test/test_range.py b/Lib/test/test_range.py
@@ -98,20 +98,24 @@ def test_large_operands(self):
        x = range(10**20+10, 10**20, 3)
        self.assertEqual(len(x), 0)
        self.assertEqual(len(list(x)), 0)
+        self.assertFalse(x)

        x = range(10**20, 10**20+10, -3)
        self.assertEqual(len(x), 0)
        self.assertEqual(len(list(x)), 0)
+        self.assertFalse(x)

        x = range(10**20+10, 10**20, -3)
        self.assertEqual(len(x), 4)
        self.assertEqual(len(list(x)), 4)
+        self.assertTrue(x)

        # Now test range() with longs
-        self.assertEqual(list(range(-2**100)), [])
-        self.assertEqual(list(range(0, -2**100)), [])
-        self.assertEqual(list(range(0, 2**100, -1)), [])
-        self.assertEqual(list(range(0, 2**100, -1)), [])
+        for x in [range(-2**100),
+                  range(0, -2**100),
+                  range(0, 2**100, -1)]:
+            self.assertEqual(list(x), [])
+            self.assertFalse(x)

        a = int(10 * sys.maxsize)
        b = int(100 * sys.maxsize)
@@ -152,13 +156,15 @@ def _range_len(x):
                step = x[1] - x[0]
                length = 1 + ((x[-1] - x[0]) // step)
            return length
+
        a = -sys.maxsize
        b = sys.maxsize
        expected_len = b - a
        x = range(a, b)
        self.assertIn(a, x)
        self.assertNotIn(b, x)
        self.assertRaises(OverflowError, len, x)
+        self.assertTrue(x)
        self.assertEqual(_range_len(x), expected_len)
        self.assertEqual(x[0], a)
        idx = sys.maxsize+1
@@ -176,6 +182,7 @@ def _range_len(x):
        self.assertIn(a, x)
        self.assertNotIn(b, x)
        self.assertRaises(OverflowError, len, x)
+        self.assertTrue(x)
        self.assertEqual(_range_len(x), expected_len)
        self.assertEqual(x[0], a)
        idx = sys.maxsize+1
@@ -194,6 +201,7 @@ def _range_len(x):
        self.assertIn(a, x)
        self.assertNotIn(b, x)
        self.assertRaises(OverflowError, len, x)
+        self.assertTrue(x)
        self.assertEqual(_range_len(x), expected_len)
        self.assertEqual(x[0], a)
        idx = sys.maxsize+1
@@ -212,6 +220,7 @@ def _range_len(x):
        self.assertIn(a, x)
        self.assertNotIn(b, x)
        self.assertRaises(OverflowError, len, x)
+        self.assertTrue(x)
        self.assertEqual(_range_len(x), expected_len)
        self.assertEqual(x[0], a)
        idx = sys.maxsize+1

diff --git a/Misc/NEWS b/Misc/NEWS
@@ -35,6 +35,9 @@ Core and Builtins
 - bpo-28893: Set correct __cause__ for errors about invalid awaitables
  returned from __aiter__ and __anext__.

+- bpo-28876: ``bool(range)`` works even if ``len(range)``
+  raises :exc:`OverflowError`.
+
 - bpo-29683: Fixes to memory allocation in _PyCode_SetExtra.  Patch by
  Brian Coleman.


diff --git a/Objects/rangeobject.c b/Objects/rangeobject.c
@@ -668,6 +668,16 @@ static PyMappingMethods range_as_mapping = {
        (objobjargproc)0,            /* mp_ass_subscript */
 };

+static int
+range_bool(rangeobject* self)
+{
+    return PyObject_IsTrue(self->length);
+}
+
+static PyNumberMethods range_as_number = {
+    .nb_bool = (inquiry)range_bool,
+};
+
 static PyObject * range_iter(PyObject *seq);
 static PyObject * range_reverse(PyObject *seq);

@@ -707,7 +717,7 @@ PyTypeObject PyRange_Type = {
        0,                      /* tp_setattr */
        0,                      /* tp_reserved */
        (reprfunc)range_repr,   /* tp_repr */
-        0,                      /* tp_as_number */
+        &range_as_number,       /* tp_as_number */
        &range_as_sequence,     /* tp_as_sequence */
        &range_as_mapping,      /* tp_as_mapping */
        (hashfunc)range_hash,   /* tp_hash */