Refuse to build over an output directory that something else modified

[jviotti]

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

[augmentcode]

🤖 Augment PR Summary

Summary: This PR makes the indexer fail fast when its output directory has been modified externally, rather than continuing an incremental build with missing cached artifacts.

Changes:

• Documents “Output Directory” ownership/constraints in the CLI help text (and updates help-output tests accordingly).
• Adds ResolverMissingCachedArtifactError to represent a cache-hit whose on-disk artifact is missing.
• Replaces a debug-only assertion in Resolver::emplace with a runtime check that throws the new error when the cached artifact path no longer exists.
• Catches the new error in the CLI entrypoint and prints a clear recovery instruction (delete output dir and re-index).
• Adds a CLI regression test that simulates deleting a schema artifact between runs.
• Adds unit tests covering both the success path (artifact present) and the failure path (artifact missing) for Resolver::emplace.

Technical Notes: The new behavior enforces the assumption that the output directory is exclusively managed by the indexer to keep incremental builds consistent.

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[augmentcode]

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[github-actions]

Benchmark Index (community)

Details

Benchmark suite	Current: d5a4e87	Previous: 868f8a0	Ratio
Add one schema (0 existing)	248 ms	320 ms	0.78
Add one schema (100 existing)	27 ms	30 ms	0.90
Add one schema (1000 existing)	98 ms	86 ms	1.14
Add one schema (10000 existing)	911 ms	733 ms	1.24
Update one schema (1 existing)	18 ms	21 ms	0.86
Update one schema (101 existing)	26 ms	29 ms	0.90
Update one schema (1001 existing)	100 ms	86 ms	1.16
Update one schema (10001 existing)	919 ms	734 ms	1.25
Cached rebuild (1 existing)	6 ms	7 ms	0.86
Cached rebuild (101 existing)	9 ms	9 ms	1
Cached rebuild (1001 existing)	33 ms	29 ms	1.14
Cached rebuild (10001 existing)	291 ms	249 ms	1.17
Index 100 schemas	378 ms	645 ms	0.59
Index 1000 schemas	1401 ms	1471 ms	0.95
Index 10000 schemas	13430 ms	14057 ms	0.96
Index 10000 schemas (custom meta-schema)	15384 ms	16806 ms	0.92
Index 10000 schemas ($ref fan-out)	15704 ms	16686 ms	0.94

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

[github-actions]

Benchmark Index (enterprise)

Details

Benchmark suite	Current: d5a4e87	Previous: 868f8a0	Ratio
Add one schema (0 existing)	400 ms	263 ms	1.52
Add one schema (100 existing)	106 ms	262 ms	0.40
Add one schema (1000 existing)	163 ms	126 ms	1.29
Add one schema (10000 existing)	826 ms	941 ms	0.88
Update one schema (1 existing)	96 ms	110 ms	0.87
Update one schema (101 existing)	102 ms	75 ms	1.36
Update one schema (1001 existing)	165 ms	176 ms	0.94
Update one schema (10001 existing)	889 ms	730 ms	1.22
Cached rebuild (1 existing)	9 ms	5 ms	1.80
Cached rebuild (101 existing)	11 ms	6 ms	1.83
Cached rebuild (1001 existing)	37 ms	17 ms	2.18
Cached rebuild (10001 existing)	315 ms	154 ms	2.05
Index 100 schemas	697 ms	1138 ms	0.61
Index 1000 schemas	1547 ms	1571 ms	0.98
Index 10000 schemas	13615 ms	10542 ms	1.29
Index 10000 schemas (custom meta-schema)	16764 ms	14967 ms	1.12
Index 10000 schemas ($ref fan-out)	16674 ms	15585 ms	1.07

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