date: fix handling of case-change flags in locale format specifiers by CrazyRoka · Pull Request #9897 · uutils/coreutils

CrazyRoka · 2025-12-28T23:23:20Z

Previously, applying flags like '^' (uppercase) or '#' (swap case) to locale-dependent specifiers (like %c, %x, %X) failed to affect the output. This occurred because the implementation passed these specifiers directly to the underlying formatter, which treats %c as a single unit without inheriting flags for its expanded components.

For example, LC_ALL=C TZ=UTC cargo run --bin coreutils date -d 2024-01-01 +%^c produced "2024 M01 1, Mon 00:00:00", whereas GNU date produces "MON JAN 1 00:00:00 2024".

This change pre-processes the format string to expand %c, %x, and %X using nl_langinfo.

This aligns behavior with GNU coreutils and we are now passing subfmt-up1 edge case in tests/date/date.pl

github-actions · 2025-12-29T02:15:10Z

GNU testsuite comparison:

Skipping an intermittent issue tests/timeout/timeout (passes in this run but fails in the 'main' branch)

sylvestre · 2025-12-29T10:35:45Z

lot of jobs are failing

github-actions · 2025-12-29T23:20:02Z

GNU testsuite comparison:

Note: The gnu test tests/id/smack was skipped on 'main' but is now failing.
Note: The gnu test tests/mkdir/smack-no-root was skipped on 'main' but is now failing.
Note: The gnu test tests/mkdir/smack-root was skipped on 'main' but is now failing.

tests/by-util/test_date.rs

src/uu/date/src/locale.rs

github-actions · 2025-12-31T21:02:09Z

GNU testsuite comparison:

GNU test failed: tests/tty/tty-eof. tests/tty/tty-eof is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/tail/overlay-headers (fails in this run but passes in the 'main' branch)

ChrisDryden · 2026-01-17T18:18:39Z

Didn't realize there was already a PR for this when I was investigating the date gnu tests failures here: #10242

I ended up making a PR to Jiff to add support for these modifiers: BurntSushi/jiff#488

These are pre-made configs actually so theres nothing stopping us from making our own custom Config that has support for all of the modifiers and this way

sylvestre · 2026-01-18T08:54:26Z

@CrazyRoka sorry, could you please rebase it ?
it looks good now

- Add documentation for distribute_flag helper. - Add unit tests for flag distribution and locale expansion. - Add integration test for locale expansion with uppercase flag.

codspeed-hq · 2026-01-18T11:56:30Z

Merging this PR will degrade performance by 3.91%

❌ 1 regressed benchmark
✅ 281 untouched benchmarks
⏩ 38 skipped benchmarks¹

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	`BASE`	`HEAD`	Efficiency
❌	Memory	`cp_large_file[16]`	115.2 KB	119.9 KB	-3.91%

_{Comparing CrazyRoka:date-implement-locale-specific (f3ab2c5) with main (d72d6f7)}

38 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. ↩

github-actions · 2026-01-18T12:01:09Z

GNU testsuite comparison:

Skipping an intermittent issue tests/tty/tty-eof (passes in this run but fails in the 'main' branch)

sylvestre · 2026-01-18T11:27:11Z

src/uu/date/src/locale.rs

    "%a %b %e %X %Z %Y"
 }

+#[cfg(not(any(


seems to be unix - no ?

I am following the pattern used elsewhere in the file. Do you suggest using #[cfg(unix)] instead?

sylvestre · 2026-01-18T11:27:36Z

src/uu/date/src/locale.rs

+    target_os = "openbsd",
+    target_os = "dragonfly"
+)))]
+pub fn expand_locale_format(format: &str) -> std::borrow::Cow<'_, str> {


why this function btw?

This is for Windows (and other non-Unix platforms). nl_langinfo is a Unix-specific libc function. On Windows we fall back to doing nothing (no expansion).

ChrisDryden · 2026-02-15T17:43:08Z

It appears all of these locale formatters were implemented using jiff-icu and the modifiers were implemented in the following PR: #10940

CrazyRoka force-pushed the date-implement-locale-specific branch from 230c85d to 3654036 Compare December 28, 2025 23:31

CrazyRoka force-pushed the date-implement-locale-specific branch 2 times, most recently from bf1c296 to f494fa5 Compare December 29, 2025 11:27

sylvestre reviewed Dec 30, 2025

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sylvestre reviewed Dec 30, 2025

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sylvestre reviewed Dec 30, 2025

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CrazyRoka force-pushed the date-implement-locale-specific branch from 65b15f3 to 49f0f26 Compare December 31, 2025 20:41

CrazyRoka force-pushed the date-implement-locale-specific branch from 49f0f26 to 0e2030a Compare January 4, 2026 10:41

ChrisDryden mentioned this pull request Jan 17, 2026

date - %x format specifier ignores locale settings #10284

Open

CrazyRoka added 2 commits January 18, 2026 11:19

date: fix handling of case-change flags in locale format specifiers

db165e9

date: address review comments (docs and tests)

f3ab2c5

- Add documentation for distribute_flag helper. - Add unit tests for flag distribution and locale expansion. - Add integration test for locale expansion with uppercase flag.

CrazyRoka force-pushed the date-implement-locale-specific branch from 0e2030a to f3ab2c5 Compare January 18, 2026 11:20

sylvestre reviewed Jan 18, 2026

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ChrisDryden closed this Feb 15, 2026

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codspeed-hq bot commented Jan 18, 2026

Merging this PR will degrade performance by 3.91%

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