printf: fix panic on width >65535 for numeric conversions

[Talha-Dmr]

Fixes #13850

printf panicked with 'Formatting argument out of range' for numeric widths above 65535. Rust's formatter limits width to u16::MAX. Use manual padding in write_output instead of format! dynamic width, similar to zero_pad_to for large precisions.

Test: printf '%65536d' 5 now outputs 65536 bytes (was panic), printf tests pass.

[Copilot]

Pull request overview

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Fixes printf panics when formatting numeric conversions with widths larger than u16::MAX by avoiding Rust’s dynamic-width formatter limitation and adding regression coverage for large numeric widths.

Changes:

• Add regression tests ensuring %65536d / %65536x no longer panic and produce correctly padded output.
• Replace write! dynamic-width formatting in numeric output with manual padding logic for large widths.

Reviewed changes

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

File	Description
tests/by-util/test_printf.rs	Adds regression tests for numeric widths above u16::MAX to prevent panics.
src/uucore/src/lib/features/format/num_format.rs	Implements manual padding/zero-padding in write_output to support large widths without formatter panics.

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[Copilot]

Pull request overview

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

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

[sylvestre]

please close the issues that have been addressed

[Talha-Dmr]

Thanks @sylvestre — resolved the addressed Copilot threads (chunked padding, DRY/unused var cleanup, checked_add + target width check, generic pad_byte handling, and InvalidInput kind). The remaining &mut writer threads were kept as is — write_output(mut writer: impl Write) is owned, so &mut writer is a single &mut W layer — but happy to change the outer signature to &mut W if you prefer.

[Copilot]

Pull request overview

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

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/cp/cp-a-selinux. tests/cp/cp-a-selinux is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/cut/bounded-memory (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/tail/tail-n0f (fails in this run but passes in the 'main' branch)
Congrats! The gnu test tests/tail/flush-initial is no longer failing!

[codspeed-hq]

Merging this PR will degrade performance by 10.16%

⚠️ 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

❌ 3 regressed benchmarks
✅ 358 untouched benchmarks
⏩ 50 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	split_lines	9.2 ms	10.6 ms	-13.16%
❌	Simulation	split_numeric_suffix	9.7 ms	11.1 ms	-12.55%
❌	Simulation	split_bytes	644.5 µs	675.1 µs	-4.53%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing Talha-Dmr:fix/printf-large-width-num-format (38a5d7b) with main (0d8310c)}

Footnotes

1. 50 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. ↩

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

[cakebaker]

Duplicate of #13857