date: re-zone trailing TZ abbreviation input to local timezone

[0xSoftBoi]

Summary

try_parse_with_abbreviation in src/uu/date/src/date.rs returned a Zoned in the input abbreviation timezone (e.g. -05 for EST). The generic parse_datetime fallback already re-zones to now.time_zone() for display, so identical inputs took two divergent paths and only one matched GNU date.

GNU treats a trailing TZ abbreviation as describing the input timezone; the output is always re-zoned into the local zone (or UTC under -u). Under TZ=UTC:

$ /usr/bin/date -d "2024-01-01 EST"Mon Jan 1 05:00:00 UTC 2024
# uutils before this PR
$ TZ=UTC target/debug/date -d "2024-01-01 EST"Mon Jan 1 00:00:00 -05 2024
# uutils after this PR
$ TZ=UTC target/debug/date -d "2024-01-01 EST"Mon Jan 1 05:00:00 UTC 2024

What changed

The abbreviation-aware path now does the same with_time_zone(now.time_zone().clone()) re-zoning the generic fallback already does. -u still produces UTC output because now is zoned to UTC in that case (date.rs:362), and the final output stage still applies with_time_zone(TimeZone::UTC) when settings.utc is set, so the existing -u + abbreviation tests (test_date_utc_with_d_flag, test_date_tz_abbreviation_fixed_offset_outside_season) are unchanged.

Testing

tests/by-util/test_date.rs already contained an #[ignore]d regression test for this issue; this PR un-ignores it. Full uu_date test suite is green locally:

test result: ok. 130 passed; 0 failed; 8 ignored; 0 measured; ...

Fixesuutils/parse_datetime#281.

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/date/date-locale-hour (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/cut/bounded-memory (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/tail/retry (passes in this run but fails in the 'main' branch)
Skip an intermittent issue tests/pr/bounded-memory (was skipped on 'main', now failing)

[codspeed-hq]

Merging this PR will improve performance by 13.71%

⚠️Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 2 improved benchmarks
✅ 315 untouched benchmarks
⏩ 46 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	ls_recursive_balanced_tree[(6, 4, 15)]	50.9 ms	48.9 ms	+4.01%
⚡	Memory	cp_recursive_deep_tree[(120, 4)]	699.2 KB	562.5 KB	+24.31%

Tip

Curious why this is faster? Comment @codspeedbot explain why this is faster on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing 0xSoftBoi:fix/281-trailing-tz-abbrev-rezones (3783654) with main (d09f351)}

Footnotes

1. 46 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[sylvestre]

nice, thanks