The following code causes an assertion error in timedelta constructor.

from datetime import timedelta

class BadInt(int):
    def __mul__(self, other):
        return Prod()

class Prod:
    def __radd__(self, other):
        return Sum()

class Sum:
    def __divmod__(self, other):
        return (0, -1)

timedelta(hours=BadInt(1))


Result:

python: /home/serhiy/py/cpython/Modules/_datetimemodule.c:1573: microseconds_to_delta_ex: Assertion `0 <= temp && temp < 1000000' failed.
Aborted (core dumped)

I got a different result in latest commit: eeb5ffd54e5

➜  cpython git:(master) ✗ ./python test.py
Traceback (most recent call last):
  File "test.py", line 15, in <module>
    timedelta(hours=BadInt(1))
SystemError: <class 'datetime.timedelta'> returned NULL without setting an error

Do I miss some configure, I'm using ./configure --with-debug

On Win10, installed 3.5.4, 3.6.3, 3.7.1a1 all raise SystemError.
3.6 and 3.7 repository debug builds raise AssertionError and Windows crash box.  After the patch, a silent crash.

Unpatched Python should crash in debug build and can raise SystemError in release build.

I can't reproduce a crash on Windows after the patch.

New changeset 4ffd4653a7ec9c97775472276cf5e159e2366bb2 by Serhiy Storchaka in branch 'master':
bpo-31752: Fix possible crash in timedelta constructor called with custom integers. (#3947)
https://github.com/python/cpython/commit/4ffd4653a7ec9c97775472276cf5e159e2366bb2

New changeset 6e45d7b90accbbdfef353c41ab0a78a3e4742803 by Serhiy Storchaka (Miss Islington (bot)) in branch '3.6':
bpo-31752: Fix possible crash in timedelta constructor called with custom integers. (GH-3947) (#4086)
https://github.com/python/cpython/commit/6e45d7b90accbbdfef353c41ab0a78a3e4742803

New changeset 5ef883b096895a84123760859f0f34ad37bf2277 by Serhiy Storchaka in branch '2.7':
[2.7] bpo-31752: Fix possible crash in timedelta constructor called with custom integers. (GH-3947) (#4088)
https://github.com/python/cpython/commit/5ef883b096895a84123760859f0f34ad37bf2277

This patch includes assertions that are easily triggered from user code: https://bugs.python.org/issue35021

New changeset 3ec0f495163da3b7a15deb2805cec48aed432f58 by Serhiy Storchaka in branch 'master':
bpo-35021: Fix assertion failures in _datetimemodule.c. (GH-10039)
https://github.com/python/cpython/commit/3ec0f495163da3b7a15deb2805cec48aed432f58

New changeset d57ab8ac182d15558118523ad1b11b029e105c46 by Miss Islington (bot) in branch '3.7':
bpo-35021: Fix assertion failures in _datetimemodule.c. (GH-10039)
https://github.com/python/cpython/commit/d57ab8ac182d15558118523ad1b11b029e105c46

New changeset 7a0d964afb41bde846771c81ba746238339cdd8c by Miss Islington (bot) in branch '3.6':
bpo-35021: Fix assertion failures in _datetimemodule.c. (GH-10039)
https://github.com/python/cpython/commit/7a0d964afb41bde846771c81ba746238339cdd8c

New changeset 40fdf471931f029ea07e6190f0fe116e0735661b by Serhiy Storchaka in branch '2.7':
[2.7] bpo-35021: Fix assertion failures in _datetimemodule.c. (GH-10039) (GH-10617)
https://github.com/python/cpython/commit/40fdf471931f029ea07e6190f0fe116e0735661b