utc to local timezone handling wrong

[LunarLanding]

Describe the bug
When importing from Google Takeout while using the sidecar information, the local timezone is applied cumulatively twice, resulting in wrong timestamps being set in Photos.

To Reproduce
Steps to reproduce the behavior:

1. What' the full command line you used with osxphotos?
   osxphotos import ./Takeout/p1 --relative-to . --walk --album "{filepath.parent}" --skip-dups --dup-albums --sidecar --verbose --keyword "{person}" --report takeout_import.csv --resume --append --split-folder "/"

No errors on the command line.

Expected behavior
UTC to local timezone transformation applied once on the sidecar timestamp.

Print-outs

Reading :

osxphotos/osxphotos/metadata_reader.py

Lines 247 to 259 in f1b2481

	if timestamp:
	try:
	date = datetime.datetime.fromtimestamp(int(timestamp))
	except ValueError:
	date = None
	if date:
	# Takeout JSON stores date as timestamp in UTC
	# regardless of timezone of photo
	# convert to naive datetime in local timezone
	# as that's what Photos uses
	date = datetime_remove_tz(
	datetime_utc_to_local(datetime_naive_to_utc(date))
	)

This is what happens now:

dt=datetime.datetime.fromtimestamp(1599158718)
print(dt,dt.tzinfo)
if dt.tzinfo is not None and dt.tzinfo.utcoffset(dt) is not None:
    raise ValueError
print(dt,dt.tzinfo)
dt=dt.replace(tzinfo=datetime.timezone.utc)
print(dt,dt.tzinfo)
dt=dt.astimezone(tz=None)
print(dt,dt.tzinfo)

2020-09-03 19:45:18 None
2020-09-03 19:45:18 None
2020-09-03 19:45:18+00:00 UTC
2020-09-03 20:45:18+01:00 WEST

This is what should be happening:

dt=datetime.datetime.fromtimestamp(1599158718,datetime.timezone.utc)
print(dt,dt.tzinfo)
dt=dt.astimezone(tz=None)
print(dt,dt.tzinfo)

2020-09-03 18:45:18+00:00 UTC
2020-09-03 19:45:18+01:00 WEST

Desktop (please complete the following information):

• OS: Sonoma 14.2.1
• osxphotos version : 0.67.0

Additional context
I might be missing some other case where setting it to UTC would fail but I'll link a pull request for now.

[RhetTbull]

These two times are the same.

When it is 2020-09-03 20:45:18+01:00 WEST

The time in UTC would be 2020-09-03 19:45:18+00:00 UTC

As UTC is one hour earlier.

What am I missing?

[LunarLanding]

datetime_remove_tz will then by doing .replace(tzinfo=None) keep only the left-side of the information, thus Photos gets in one case the wrong one 2020-09-03 20:45:18, and in another the correct one 2020-09-03 19:45:18.

The input to datetime_utc_to_local should be independent of the local timezone, but it is not.

[RhetTbull]

Google converts local timezone to UTC in the Takeout sidecar. This local timezone of where the photo was taken is lost. If imported into Photos without conversion Photos will assume the timezone is local timezone. But the time in UTC is not correct for local timezone (unless local is UTC), thus the conversion. I've tested this on a test case for which I know the correct local time and it appears to be working. Entirely possible I've messed up something but I don't understand the situation at the moment. The desired outcome is that the UTC time is translated to the equivalent time in the local timezone. I'm traveling and don't have my Mac with me so can't test at the moment.

[RhetTbull]

Ok, I think I see the issue. The initial conversion from timestamp converts a naive time into naive timestamp in local timezone. This may be occurring elsewhere (Eg parse date) so need to ensure that code path is also correct.