fix(mutate): modify --add-tag drops the WHOLE FILE when a tag needs quoting (REQ-287, P0 data loss)

[avrabe]

P0 silent data loss found by a mutation-path stress test (your report: modifying artifacts "very often" fails).

The bug

rivet-core/src/yaml_edit.rs re-emitted the tag flow list via current_tags.join(", ") without quoting individual tags — unlike the hardened setters (title/status/field, #687) and the add path. Any tag with a YAML flow indicator (: , ,, […) breaks.

Worst case — corruption from a benign operation: an artifact with a legitimately-quoted tag "release: v1.0", hit by an unrelated --add-tag simpletag, gets the quotes stripped → [alpha, release: v1.0, …] → the flow list becomes a map → the whole file fails to parse → every artifact in it vanishes — while modify exits 0 reporting "modified".

Reproduced: 2 artifacts → benign --add-tag → 0 loadable.

The fix

Quote each tag via yaml_quote_inline_scalar before joining (one-line change mirroring the already-hardened add path). Also closes a silent-split variant (--add-tag "a,b" stored two tags).

Verification

• Reproduced the data loss, confirmed the fix restores 2/2 artifacts and keeps "release: v1.0" quoted.
• New rivet-cli regression test (verifies REQ-287); all 38 yaml_edit unit tests still pass.
• validate PASS, docs check 0 violations, clippy --all-targets -D warnings 0, fmt clean.

Context

Same tag-mutation fragility class as #625, on the quoting axis. The broader mutation-path audit found only this live defect — set-field/link/unlink/sql UPDATE/add all preserved rich content faithfully (the surgical yaml_edit.rs editor was already hardened elsewhere). Part of v0.32.

Fixes: REQ-287

🤖 Generated with Claude Code

[github-actions]

📐 Rivet artifact delta

Change	Count
Added	1
Removed	0
Modified	0
Downstream impacted (depth ≤ 5)	0

Graph

graph LR
  REQ_287["REQ-287"]:::added
  classDef added fill:#d4edda,stroke:#28a745,color:#155724
  classDef removed fill:#f8d7da,stroke:#dc3545,color:#721c24
  classDef modified fill:#fff3cd,stroke:#ffc107,color:#856404
  classDef overflow fill:#e2e3e5,stroke:#6c757d,color:#495057,stroke-dasharray: 3 3

Loading

Added

• REQ-287

📎 Full HTML dashboard attached as workflow artifact rivet-delta-pr-765 — download from the workflow run.

_{Posted by rivet-delta workflow. The graph shows only changed artifacts; open the HTML dashboard (above) for full context.}

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'Rivet Criterion Benchmarks'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.20.

Benchmark suite	Current: f643607	Previous: e1a539f	Ratio
store_insert/100	87080 ns/iter (± 1131)	67561 ns/iter (± 2504)	1.29
store_lookup/100	2139 ns/iter (± 7)	1441 ns/iter (± 56)	1.48
store_lookup/1000	26780 ns/iter (± 740)	16101 ns/iter (± 513)	1.66
store_lookup/10000	388257 ns/iter (± 1955)	260752 ns/iter (± 5937)	1.49
store_by_type/100	96 ns/iter (± 0)	68 ns/iter (± 1)	1.41
store_by_type/1000	96 ns/iter (± 0)	66 ns/iter (± 1)	1.45
store_by_type/10000	96 ns/iter (± 0)	69 ns/iter (± 3)	1.39
schema_load_and_merge	1523862 ns/iter (± 25304)	1193878 ns/iter (± 46244)	1.28
validate/100	480866 ns/iter (± 2271)	378790 ns/iter (± 17921)	1.27
validate/1000	15076684 ns/iter (± 113051)	12070154 ns/iter (± 340350)	1.25
validate/10000	1247387288 ns/iter (± 11110283)	831299935 ns/iter (± 15730153)	1.50
traceability_matrix/100	4466 ns/iter (± 27)	3149 ns/iter (± 112)	1.42
traceability_matrix/1000	64051 ns/iter (± 204)	33943 ns/iter (± 1312)	1.89
diff/100	61516 ns/iter (± 401)	48775 ns/iter (± 1179)	1.26
diff/1000	699381 ns/iter (± 3519)	501545 ns/iter (± 12268)	1.39
diff/10000	7712715 ns/iter (± 338666)	6139888 ns/iter (± 159935)	1.26
query/100	1179 ns/iter (± 3)	780 ns/iter (± 17)	1.51
query/1000	15237 ns/iter (± 94)	9884 ns/iter (± 463)	1.54
query/10000	332404 ns/iter (± 1501)	258837 ns/iter (± 4830)	1.28
document_parse/10	24101 ns/iter (± 182)	18495 ns/iter (± 554)	1.30
document_parse/100	168472 ns/iter (± 1793)	128852 ns/iter (± 4536)	1.31
document_parse/1000	1581448 ns/iter (± 11809)	1182878 ns/iter (± 32105)	1.34

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

[codecov]

Codecov Report

❌ Patch coverage is 0% with 6 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
rivet-core/src/yaml_edit.rs	0.00%	6 Missing ⚠️

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