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This page is meant to document Python issues of general interest to Kodi addon developers.
datetime.strptime
There is an old Python bug[1] which only impacts embedded Python applications, such as the Kodi Python environment. The issue is that datetime.strptime[2] is only initialized once per process, and not every time the embedded environment is reinitialized. This causes datetime.strptime to return None (and perhaps other strange behavior).
Resolution options
One option is for you to replace every reference to datetime.strptime to use a patch, the code of which is shown below on this page. This involves less voodoo, but there is always the possibility that some library code uses strptime and that will cause the potential for incorrect results or a full Kodi crash, e.g. the YouTube-dl add-on (script.module.youtube.dl) was crashing Kodi for a while.
The other option is to monkey-patch datetime.strptime so that any user of the Python runtime will use it. It is more voodoo-like, but situations like this are why Python natively supports monkey patching, after all. The typically excellent Python documentation manages to be both thorough and concise simultaneously with regards to datetime.strptime and is well worth reviewing before deciding which angle of attack best suits your use case.[3]; it discusses some of the differences between datetime.strptime and time.strptime.[4]
Patch
This patch simply replaces datetime.strptime with time.strptime as they are nearly identical in function. The original Kodi-specific implementation and its commit history are available on GitHub as part of script.module.kutils.[5] Essentially, the patch is:
@staticmethod
def monkey_patch_strptime():
# Check if problem exists (don't want to stomp on patch applied earlier)
try:
datetime.datetime.strptime('0', '%H')
except TypeError:
# Globally replace Python's datetime.datetime.strptime with
# the version here.
datetime.datetime = StripTimePatch.strptime
@staticmethod
def strptime(date_string: str, date_format: str) -> datetime.datetime:
result: datetime.datetime
result = datetime.datetime(*(time.strptime(date_string, date_format)[0:6]))
return result
References
- ↑ Weinberg, Denny (June 27, 2016). Issue #71587: Datetime NoneType after calling Py_Finalize and Py_Initialize. Python Issue Tracker on GitHub.
- ↑ Python 3 Documentation (August 28, 2022). The Python Standard Library » Data Types » datetime — Basic date and time types ― classmethod datetime.strptime(date_string, format) ― from the source code found in Lib/datetime.py.
- ↑ Python 3 Documentation (August 28, 2022). datetime — Basic date and time types » strftime() and strptime() Behavior.
- ↑ Python 3 Documentation (August 28, 2022). strftime() and strptime() Behavior » Technical Detail.
- ↑ lib/kutils/strptime_patch.py (January 11, 2022) in
script.module.kutils, "A helper module for Kodi development" on GitHub.