datetime.timestamp() fails before 1970-01-02T01:00:00.000000

[dtyeos]

Python 3.8.10
datetime 4.4
Windows 10

datetime(1970,1,1,0,0,0).timestamp()  # OSError: [Errno 22] Invalid argument
datetime(1970,1,1,23,59,59,999999).timestamp()  # OSError: [Errno 22] Invalid argument
datetime(1970,1,2,0,59,59,999999).timestamp()  # OSError: [Errno 22] Invalid argument

Minimal datetime where timestamp() is fine:

datetime(1970,1,2,1,0,0).timestamp()  # 86400.0

[dtyeos]

Probable duplicate of gh-81708¹

Footnotes

1. @erlend-aasland: edited the BPO link to a GitHub Issues link, for the convenience of the reader ↩

[dtyeos]

datetime(1970,1,1,0,0,0, tzinfo=None).timestamp()  # OSError: [Errno 22] Invalid argument
datetime(1970,1,1,0,0,0, tzinfo=timezone.utc).timestamp()  # 0.0

[dignissimus]

Cannot reproduce this on Arch with python 3.10.5 with the system clock set to UTC+1. Perhaps this only affects Windows. Are you able to reproduce this using python 3.10?

sam@samtop ~ % python                                                  
Python 3.10.5 (main, Jun  6 2022, 18:49:26) [GCC 12.1.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from datetime import datetime, timezone
>>> datetime(1970,1,1,0,0,0, tzinfo=None).timestamp()
-3600.0
>>> datetime(1970,1,1,0,0,0, tzinfo=timezone.utc).timestamp()
0.0
>>> import time
>>> time.tzname
('GMT', 'BST')
>>> 

[dtyeos]

C:\>py -3.10
Python 3.10.5 (tags/v3.10.5:f377153, Jun  6 2022, 16:14:13) [MSC v.1929 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from datetime import datetime, timezone
>>> datetime(1970,1,1,0,0,0, tzinfo=None).timestamp()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: [Errno 22] Invalid argument
>>> datetime(1970,1,1,0,0,0, tzinfo=timezone.utc).timestamp()
0.0
>>> import time
>>> time.tzname
('Romance Standard Time', 'Romance Daylight Time')
>>>

This should come from the fact that without any timezone specified, the lib relies on the Windows function which does not support times before the Epoch. The strange thing is that the whole day after the Epoch is unusable, which cannot be explained only by time zone.

[benpryke]

While running property-based tests with Hypothesis, I discovered that datetime.timestamp() also fails with the same error on Windows 10 x64 for datetimes after datetime.datetime(3001, 1, 19, 7, 59, 59, 999999).

Specifically:

> datetime.datetime(3001, 1, 19, 7, 59, 59, 999999).timestamp()
32536800000.0
> datetime.datetime(3001, 1, 19, 8, 0, 0, 0).timestamp()
OSError: [Errno 22] Invalid argument

I suspect this is related to the max value of the argument to time.ctime on Windows 10 x64 as discussed in this Stack Overflow thread.