[Dev] datetime.datetime.utcnow() deprecated and replacement breaks strptime

[DanielYang59]

datetime.datetime.utcnow() deprecated

See discussion in #3705 (comment), datetime.datetime.utcnow() is marked as deprecated and might be removed after Python 3.12.

The same issue has been reported to monty as well: materialsvirtuallab/monty#275.

But the new replacement returns slightly different output (an additional timezone info +00:00 at the end), which breaks strptime:

import datetime

start_time_old = datetime.datetime.utcnow()  # 2024-03-25 08:46:23.748342 

start_time_new = datetime.datetime.now(datetime.UTC)  # 2024-03-25 08:46:23.748472+00:00

print(start_time_old, start_time_new)  


dt_old = datetime.datetime.strptime(
    str(start_time_old), "%Y-%m-%d %H:%M:%S.%f"
)
print(dt_old)


dt_new = datetime.datetime.strptime(
    str(start_time_new), "%Y-%m-%d %H:%M:%S.%f"
)
print(dt_new)

Raises:

Traceback (most recent call last):
  File "/Users/yang/developer/test/test.py", line 16, in <module>
    dt = datetime.datetime.strptime(
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/[email protected]/3.12.2_1/Frameworks/Python.framework/Versions/3.12/lib/python3.12/_strptime.py", line 554, in _strptime_datetime
    tt, fraction, gmtoff_fraction = _strptime(data_string, format)
                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/[email protected]/3.12.2_1/Frameworks/Python.framework/Versions/3.12/lib/python3.12/_strptime.py", line 336, in _strptime
    raise ValueError("unconverted data remains: %s" %
ValueError: unconverted data remains: +00:00

[DanielYang59]

It seems I cannot re-open this for some reason. This was closed by the accidentally included to fix keyword but was not fixed.

7fac0b4 need to fix #3791

[DanielYang59]

Thanks for the fix @janosh, the Windows tests failing in CI is due to a matplotlib issue 628f737, but that PR #3887 would need some extra time to be reviewed. Perhaps you could fix that directly on master?

Meanwhile it looks like one unit test for util.provenance is broken, probably because the new API is not a drop-in replacement (with additional timezone info at the end):

import datetime


print(datetime.datetime.utcnow())  >>> 2024-08-04 12:55:17.167352
print(datetime.datetime.now(tz=datetime.timezone.utc))   >>> 2024-08-04 12:55:17.167478+00:00

[janosh]

thanks, good call!