Use UTC times consistently

[nathanjmcdougall]

Regarding this comment:

pins-python/pins/versions.py

Lines 77 to 78 in d215a8c

	# TODO: the datetime from pins is not timezone aware, but it looks like
	# R pins parses as UTC, then unsets the UTC part?

As far as I can tell, R pins will write the created datetime as a UTC time:

https://github.com/rstudio/pins-r/blob/de47c3141d97020e9f4a6a2e93d5823bc649105b/R/meta.R#L50

And the functions it uses to parse datetimes also specify UTC (although the two parse_ functions indeed strip it out).
https://github.com/rstudio/pins-r/blob/de47c3141d97020e9f4a6a2e93d5823bc649105b/R/meta.R#L55-L68

I haven't looked into this too deeply though.

As far as I can tell, Python pins will just use the local datetime, e.g.

pins-python/pins/versions.py

Line 104 in d215a8c

created = datetime.now()

I suggest that this behaviour is changed (this is arguably a breaking change, arguably a bugfix) to use UTC consistently everywhere. To that end, the DTZ rules in ruff could be helpful to enable.

In any case, I think it would be worth documenting this behaviour in more detail.

[jeffkeller-einc]

This tripped me up for longer than I care to admit today. My workaround was to set the environment variable TZ=utc so that Python pins detected the local timezone as UTC.