bpo-27145: small_ints[x] could be returned in long_add and long_sub (GH-15716)
diff --git a/Lib/test/test_long.py b/Lib/test/test_long.py
index 53101b3..7ce37e8 100644
--- a/Lib/test/test_long.py
+++ b/Lib/test/test_long.py
@@ -956,6 +956,14 @@
self.assertEqual(huge >> (sys.maxsize + 1), (1 << 499) + 5)
self.assertEqual(huge >> (sys.maxsize + 1000), 0)
+ @support.cpython_only
+ def test_small_ints_in_huge_calculation(self):
+ a = 2 ** 100
+ b = -a + 1
+ c = a + 1
+ self.assertIs(a + b, 1)
+ self.assertIs(c - a, 1)
+
def test_small_ints(self):
for i in range(-5, 257):
self.assertIs(i, i + 0)
diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-09-06-16-40-12.bpo-27145.njuCXU.rst b/Misc/NEWS.d/next/Core and Builtins/2019-09-06-16-40-12.bpo-27145.njuCXU.rst
new file mode 100644
index 0000000..229753a
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2019-09-06-16-40-12.bpo-27145.njuCXU.rst
@@ -0,0 +1 @@
+int + int and int - int operators can now return small integer singletons. Patch by hongweipeng.
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 294308e..f056797 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3206,7 +3206,7 @@
if (sign < 0) {
Py_SIZE(z) = -Py_SIZE(z);
}
- return long_normalize(z);
+ return maybe_small_long(long_normalize(z));
}
static PyObject *
@@ -3254,13 +3254,15 @@
return PyLong_FromLong(MEDIUM_VALUE(a) - MEDIUM_VALUE(b));
}
if (Py_SIZE(a) < 0) {
- if (Py_SIZE(b) < 0)
- z = x_sub(a, b);
- else
+ if (Py_SIZE(b) < 0) {
+ z = x_sub(b, a);
+ }
+ else {
z = x_add(a, b);
- if (z != NULL) {
- assert(Py_SIZE(z) == 0 || Py_REFCNT(z) == 1);
- Py_SIZE(z) = -(Py_SIZE(z));
+ if (z != NULL) {
+ assert(Py_SIZE(z) == 0 || Py_REFCNT(z) == 1);
+ Py_SIZE(z) = -(Py_SIZE(z));
+ }
}
}
else {