Drop built-in atomicity support in favour of OverlayFS

[jviotti]

Signed-off-by: Juan Cruz Viotti jv@jviotti.com

[cubic-dev-ai]

No issues found across 13 files

[augmentcode]

🤖 Augment PR Summary

Summary: This PR removes One’s built-in “atomic commit” mechanism for index output generation, shifting responsibility for atomicity to the execution environment (e.g., OverlayFS).

Changes:

• Drops the staging directory + sentinel strategy and the final atomic directory swap in src/index/index.cc.
• Writes build artifacts directly into the final output path via sourcemeta::one::Output.
• Removes commit-related CLI log lines (no more “Hardlinking:” / “Committing:” messages).
• Moves the <fstream> dependency to src/index/output.h (where std::ofstream is used).
• Updates CLI golden-output tests to match the new logging behavior.
• Removes CLI tests that specifically validated staging/atomic-failure/stale-staging behaviors.

Technical Notes: After this change, a failed indexing run can leave the output directory partially updated unless an external atomicity layer (like OverlayFS) is used.

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[augmentcode]

Review completed. 2 suggestions posted.

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[augmentcode]

Now that Output targets final_output_path directly, any failure after this point can leave the real output directory partially updated/created (where previously the atomic swap avoided touching it). If non-OverlayFS runs are still supported, it may be worth documenting/warning about this behavioral change to avoid surprising data loss.

Severity: medium

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[augmentcode]

PROFILE_END(profiling, "Commit") now appears to measure an empty stage (the commit/swap logic was removed), which can make --time output misleading. Consider removing or renaming this profiling label so timings reflect real work.

Severity: low

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[github-actions]

Benchmark Index (community)

Details

Benchmark suite	Current: 6144844	Previous: 2cbd5ce	Ratio
Add one schema (0 existing)	41 ms	44 ms	0.93
Add one schema (100 existing)	452 ms	1000 ms	0.45
Add one schema (1000 existing)	4566 ms	9431 ms	0.48

This comment was automatically generated by workflow using github-action-benchmark.

[github-actions]

Benchmark Index (enterprise)

Details

Benchmark suite	Current: 6144844	Previous: 2cbd5ce	Ratio
Add one schema (0 existing)	45 ms	53 ms	0.85
Add one schema (100 existing)	484 ms	1110 ms	0.44
Add one schema (1000 existing)	4576 ms	10658 ms	0.43

This comment was automatically generated by workflow using github-action-benchmark.