yama: add soundness/polarity lens + 2 blocking criteria (review follow-up to #56)

[jagguji]

What

Follow-up to #56 (merged before this feedback could be folded in). Applies the three review suggestions to yama.config.yaml so the AI reviewer is pointed at the one blind spot it currently has — an unsound type that compiles.

Why

The config (correctly) steers Yama away from re-running the mechanical CI gates, and blocks Obj.magic/@unwrap/%identity. But the highest-value bugs in our review history were none of those — they compiled green on every gate and needed a human:

• Bind Record|Array<{…value:any}> unions exactly — base-ui 195/0/0, last review component (#50) #55 — an any field on a getter return became an output-only 'a (routes(): RouterRoute<'a>[]) that unifies with anything. bench was 8/8.
• base-ui review remainders: Ref unions, container from* views, LocalesArgument — review 28 → 9 (#39) #40 — a fake => string return hidden inside a shared @unboxed, rendered unflagged.
• Exact views for collisionBoundary/anchor/finalFocus — base-ui review 13 → 1 (#39) #49 — a union variant silently dropped on a constructor-ident collision.

As configured, the reviewer would likely miss these too. This PR closes that.

Changes (config-only — does not touch the generator)

1. workflowInstructions — a "compilation is NOT soundness" lens (CI proves compiles + matches baseline, not soundness; a fake behind a shared typeRef doesn't bubble to the report) + a PRODUCE/RECEIVE polarity rule ('a is sound only in a consumer-supplied input).
2. focusAreas (mapping correctness) — an all-cases-or-flag line: every union/overload variant must be reachable, or the whole prop is flagged — never silently dropped.
3. blockingCriteria (4 → 6) — (a) an output-only 'a that doesn't round-trip; (b) a fake emitted UNFLAGGED inside a shared *Types.res entry.

Verified: all five additions present, blocking criteria count 4 → 6, indentation mirrors the existing entries. (No YAML linter available locally; structure matches the surrounding blocks exactly.)

[github-actions]

Benchmark: ✅ PASS

Package	Compile	Diff vs baseline	usable	review	broken	Verdict
@juspay/blend-design-system@0.0.36	✅	identical	94	0	0	✅ PASS
react-day-picker@10.0.1	✅	identical	27	0	0	✅ PASS
react-tooltip@6.0.7	✅	identical	1	0	0	✅ PASS
react-markdown@10.1.0	✅	identical	0	2	0	✅ PASS
@smastrom/react-rating@1.5.0	✅	identical	1	0	0	✅ PASS
clsx@2.1.1	✅	identical	0	0	0	✅ PASS
hono@4.12.25	✅	identical	0	0	0	✅ PASS
@base-ui-components/react@1.0.0-rc.0	✅	identical	195	0	0	✅ PASS

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@juspay/rescript-bindgen@58

commit: ef903fd

[jagguji]

Thanks for the thorough review — and for running the YAML parse I couldn't (good to have psych confirm the backticks/colons/apostrophes in the quoted strings are clean).

Applied your one actionable note: tightened the hidden-fake criterion to curb false positives. It now requires the reviewer to VERIFY against the original .d.ts that the TS type was genuinely richer (union/object/callback) and got narrowed to string before blocking — and says explicitly that a field legitimately typed string in TypeScript is not a violation. That should stop it BLOCKing on every honest string field.

On your other two notes — both intentional, leaving as-is:

• The polarity idea appearing in 3 places is deliberate reinforcement for an LLM prompt (not accidental redundancy).
• Agreed there's no mechanical gate that proves the reviewer will catch these — it's guidance, and the only real signal is whether the next soundness regression gets caught in review. The PR is honest about that.

Pushed as ef903fd.

[Tara-ag]

Review Summary

File reviewed: yama.config.yaml (1 file, +27 lines)

New issues raised: 0

Assessment

This PR successfully adds critical soundness guidance to the Yama review configuration based on lessons from issues #55, #40, and #49. The changes are:

1. CRITICAL LENS — Compilation is NOT soundness; CI gates prove compilation + baseline match, not type safety
2. POLARITY — 'a is only sound in consumer-supplied INPUT positions (round-trips); OUTPUT-only 'a unifies with anything
3. All-cases-or-flag — Every union/overload variant must be reachable; never silently drop cases
4. Two new blocking criteria — Output-only 'a and unflagged fakes in shared types now block merges

Verification:

• ✅ YAML structure valid with consistent 2-space/4-space indentation
• ✅ Blocking criteria count: 4 → 6 (matches PR description)
• ✅ All three historical issues (#55, #40, #49) addressed in guidance
• ✅ Config-only change — no generator code modified

Decision: Approve. The tightened criteria will help catch unsound types that compile successfully, addressing the highest-value blind spot in automated review.