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authorBrandt Bucher <brandtbucher@gmail.com>2020-02-01 03:08:34 -0800
committerGitHub <noreply@github.com>2020-02-01 11:08:34 +0000
commitabb9a448dee3e18c69080231fbeba980bf048211 (patch)
treee95970aaf1c048045b8faedc114810263c36c541 /Python/bltinmodule.c
parent4d96b4635aeff1b8ad41d41422ce808ce0b971c8 (diff)
downloadcpython-git-abb9a448dee3e18c69080231fbeba980bf048211.tar.gz
Update sum comment. (#18240)
Diffstat (limited to 'Python/bltinmodule.c')
-rw-r--r--Python/bltinmodule.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index 4f833c1f46..5818eb9e38 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -2440,7 +2440,11 @@ builtin_sum_impl(PyObject *module, PyObject *iterable, PyObject *start)
empty = []
sum([[x] for x in range(10)], empty)
- would change the value of empty. */
+ would change the value of empty. In fact, using
+ in-place addition rather that binary addition for
+ any of the steps introduces subtle behavior changes:
+
+ https://bugs.python.org/issue18305 */
temp = PyNumber_Add(result, item);
Py_DECREF(result);
Py_DECREF(item);