[ChihweiLHBird]

cksum --raw writes the digest without a newline, so it stays in the writer's buffer until the writer is dropped, and a drop cannot report an error. On a full disk, cksum --raw f > out leaves an empty file and exits 0. GNU exits 1 with write error: No space left on device.

This flushes before the early return, so the error goes through the normal write-error path and sets the exit code. The new test sends raw output to /dev/full and expects exit 1 with that message.

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[codspeed]

Merging this PR will improve performance by 28.55%

1 warning, 1 note

⚠️ 120 benchmarks are dominated by system calls

System calls cannot be simulated consistently and are left out of the measure. The reported value understates the real cost. Switch to the Walltime instrument to measure them.

Learn more about system calls

See affected benchmarks

ℹ️ 1 benchmark has no flamegraph

The flamegraph wasn't generated: most of the time was spent in runtime internals, which would leave nothing useful to analyze.

See affected benchmarks

⚡ 2 improved benchmarks
✅ 399 untouched benchmarks
⏩ 70 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	CPU Simulation	complex_relative_date	386.2 µs	277.7 µs	+39.05%
⚡	CPU Simulation	true_consecutive_calls	350.2 ns	294.7 ns	+18.85%

Tip

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

---

_{Comparing ChihweiLHBird:zhiwei/cksum-raw-flush (3d5d4e6) with main (4939cd4)²}

Footnotes

1. 70 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. ↩

2. No successful run was found on main (2f8b194) during the generation of this report, so 4939cd4 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[xtqqczze]

@ChihweiLHBird Is there an existing issue that covers this work?

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[ChihweiLHBird]

@ChihweiLHBird Is there an existing issue that covers this work?

I didn't find any

[xtqqczze]

Fuzzing failures tracked by #15567.

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[sylvestre]

Thanks for your PR