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fmt: fix fmt /dev/zero panic#10602

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mattsu2020 wants to merge 5 commits intouutils:mainfrom
mattsu2020:fmt_devzero
Open

fmt: fix fmt /dev/zero panic#10602
mattsu2020 wants to merge 5 commits intouutils:mainfrom
mattsu2020:fmt_devzero

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@mattsu2020 mattsu2020 commented Jan 30, 2026

Summary

Prevent unbounded line buffering in fmt by introducing a capped, incremental line reader.
Split oversized paragraphs by byte/line thresholds to keep memory bounded on infinite input.

related
#10580

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github-actions Bot commented Jan 31, 2026

GNU testsuite comparison:

Skipping an intermittent issue tests/shuf/shuf-reservoir (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/sort/sort-stale-thread-mem (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/tail/inotify-dir-recreate (passes in this run but fails in the 'main' branch)
Congrats! The gnu test tests/basenc/bounded-memory is now passing!

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github-actions Bot commented Feb 3, 2026

GNU testsuite comparison:

Skipping an intermittent issue tests/tail/follow-name (passes in this run but fails in the 'main' branch)

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github-actions Bot commented Feb 14, 2026

GNU testsuite comparison:

GNU test failed: tests/pr/bounded-memory. tests/pr/bounded-memory is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/tail/symlink (fails in this run but passes in the 'main' branch)
Congrats! The gnu test tests/factor/t33 is no longer failing!
Congrats! The gnu test tests/factor/t34 is no longer failing!
Note: The gnu test tests/tail/pipe-f is now being skipped but was previously passing.

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codspeed-hq Bot commented Feb 14, 2026 •
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Merging this PR will not alter performance

✅ 299 untouched benchmarks
⏩ 46 skipped benchmarks1

Comparing mattsu2020:fmt_devzero (a6a7472) with main (e0f0318)

Open in CodSpeed

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. ↩

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github-actions Bot commented Feb 14, 2026

GNU testsuite comparison:

GNU test failed: tests/factor/t10. tests/factor/t10 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/factor/t33. tests/factor/t33 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/factor/t34. tests/factor/t34 is passing on 'main'. Maybe you have to rebase?
Skipping an intermittent issue tests/tty/tty-eof (passes in this run but fails in the 'main' branch)
Congrats! The gnu test tests/factor/t28 is no longer failing!
Congrats! The gnu test tests/cut/cut-huge-range is now passing!
Congrats! The gnu test tests/rm/many-dir-entries-vs-OOM is now passing!

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github-actions Bot commented Feb 18, 2026

GNU testsuite comparison:

GNU test failed: tests/timeout/timeout-group. tests/timeout/timeout-group is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/tail/symlink (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/pr/bounded-memory (passes in this run but fails in the 'main' branch)
Note: The gnu test tests/basenc/bounded-memory is now being skipped but was previously passing.

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github-actions Bot commented Feb 18, 2026

GNU testsuite comparison:

GNU test failed: tests/date/date-locale-hour. tests/date/date-locale-hour is passing on 'main'. Maybe you have to rebase?
Congrats! The gnu test tests/cut/bounded-memory is no longer failing!
Note: The gnu test tests/printf/printf-surprise is now being skipped but was previously passing.
Note: The gnu test tests/rm/many-dir-entries-vs-OOM is now being skipped but was previously passing.

@mattsu2020
refactor: simplify line length assertions in fmt tests
78e0898 
Replace verbose closure syntax with method reference for cleaner, more idiomatic test assertions.
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github-actions Bot commented Feb 28, 2026

GNU testsuite comparison:

Skipping an intermittent issue tests/date/date-locale-hour (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/tail/symlink (passes in this run but fails in the 'main' branch)
Congrats! The gnu test tests/timeout/timeout-group is no longer failing!
Note: The gnu test tests/seq/seq-epipe is now being skipped but was previously passing.
Congrats! The gnu test tests/tail/tail-n0f is now passing!

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github-actions Bot commented Mar 24, 2026

GNU testsuite comparison:

Skip an intermittent issue tests/cut/bounded-memory (fails in this run but passes in the 'main' branch)
Congrats! The gnu test tests/csplit/csplit-heap is now passing!

sylvestre
sylvestre requested changes Mar 24, 2026
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too much added complexity for a rare case
please simplify it

@mattsu2020 mattsu2020 marked this pull request as draft March 24, 2026 11:10
@mattsu2020
refactor: simplify line reading logic and remove paragraph limits
6549773 
- Removed MAX_PARAGRAPH_BYTES and MAX_PARAGRAPH_LINES constants
- Simplified read_line_limited() to read_limited_line() with cleaner logic
- Improved handling of pending bytes and line splitting
- Removed unused paragraph-related code and constants
- Enhanced memory management for large lines without newlines
@mattsu2020
refactor: extract line ending stripping logic into dedicated method
a6a7472 
Extracted the repeated logic for removing trailing LF or CRLF line endings into a dedicated `strip_line_ending` method to improve code maintainability and reduce duplication across the `read_limited_line` function.
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github-actions Bot commented Mar 24, 2026

GNU testsuite comparison:

Skip an intermittent issue tests/date/resolution (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)
Note: The gnu test tests/tail/tail-n0f is now being skipped but was previously passing.

@mattsu2020 mattsu2020 requested a review from sylvestre March 24, 2026 11:43
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mattsu2020 commented Mar 24, 2026

too much added complexity for a rare case please simplify it

I tried to keep it as simple as possible

@mattsu2020 mattsu2020 marked this pull request as ready for review March 24, 2026 11:43
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@sylvestre sylvestre Awaiting requested review from sylvestre

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