Add fold to the datetime fieldtype to resolve datetime ambiguity

[Miauwkeru]

This is for disambiguation during dst time

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.23%. Comparing base (a30f10d) to head (4925eb1).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #217   +/-   ##
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  Coverage   84.23%   84.23%           
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  Files          35       35           
  Lines        3742     3742           
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  Hits         3152     3152           
  Misses        590      590           

Flag	Coverage Δ
unittests	84.23% <ø> (ø)

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[Miauwkeru]

Something I noticed when writing fox-it/dissect.target#1614
The fold argument isn't passed through

[Copilot]

Pull request overview

This PR addresses DST ambiguity by preserving the datetime.fold attribute when flow.record.fieldtypes.datetime is constructed from an existing datetime instance, and adds tests to validate correct behavior around DST transitions.

Changes:

• Preserve fold when converting from a datetime object inside the datetime fieldtype.
• Extend datetime fieldtype tests to cover fold=1 and an end-of-DST scenario using Europe/Amsterdam.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
flow/record/fieldtypes/__init__.py	Propagates arg.fold when wrapping an existing datetime into the fieldtype.
tests/fieldtypes/test_fieldtypes.py	Adds parametrized tests and an explicit DST fold example using ZoneInfo.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

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[yunzheng]

LGTM, added an additional test and skip tests if zoneinfo is not available.