[ruaridhw]

Pickling pendulum DateTimes doesn't preserve before vs after DST effects. See #908

Pull Request Check List

• Added tests for changed code.
• Updated documentation for changed code.

[ashb]

Please add some unit tests to prevent regressions

[codspeed]

CodSpeed Performance Report

Merging #909 will not alter performance

_{Comparing ruaridhw:patch-1 (63a658f) with master (2adcc02)}

Summary

✅ 1 untouched benchmarks

[Duo-ee]

Heads-up: I opened #1073 as a fix for #908 that also carries the regression tests this PR was asked for.

One thing worth knowing about restoring through self.create: it re-resolves the wall time in the timezone instead of rebuilding the instance, so it also changes things beyond the fold. On master, with your patch applied locally, I measured:

• a zoneinfo.ZoneInfo tzinfo comes back as FixedTimezone/Timezone
• a wall time that does not exist (2024-03-10 02:30 in America/Chicago, only reachable through the constructor) is moved to 01:30, so its timestamp changes by an hour

#1073 keeps create() out of the path and rebuilds via cls(*state, fold=fold).

Not asking you to do anything with this PR; if you would rather land the fix here, the tests in #1073 apply as they are.