M1/PR16: review blocker set — typed-spine leaks and silent route rewriting (F01 F02 F03 F04 F06 F12) #17

Source: multi-agent review of PR #16 (range 3e3e058871...52a5e3b1fd), adversarially verified 2026-08-13. This issue is the canonical record; the scratchpad review artifacts are ephemeral. Fix red-test-first; closed by the PR that lands the fixes.

Checklist

• F01 — Invalid charset escapes the typed exception spine · CONFIRMED · sev 4/5 · shipped-runtime. Pipeline.ReadBodyAsync (src/OpenCode.Sdk/Internal/Pipeline.cs:148-152) catches only HttpRequestException or IOException or ObjectDisposedException; HttpContent.ReadAsStringAsync throws InvalidOperationException (inner ArgumentException) on Content-Type: application/json; charset=not-an-encoding — verified on modern runtimes and net472. Escapes OpenCodeException spine on every operation; NoThrow cannot intercept (body read at :92 precedes the ErrorBehavior decision at :95-98). Fix: add InvalidOperationException to the filtered catch, wrap as OpenCodeTransportException, keep OperationCanceledException untouched. Test: invalid-charset content asserting OpenCodeTransportException with IOE inner.
• F02 — Unexpected 2xx enters the API-error channel · CONFIRMED · medium · both M1 operations. Written contract: "Unexpected or malformed 2xx responses are protocol failures" (docs/superpowers/plans/2026-08-13-m1-arc-b-callable-client.md:41). Generated adapters (HealthResponseAdapter.cs:37, same in SessionMessageResponseAdapter, emitted by ResponseAdapterEmitter.cs:86-119) route 201/204/299 to the error envelope instead of OpenCodeTransportException. Fix in ResponseAdapterEmitter: declared 200 = success; other 2xx arm throws OpenCodeTransportException; non-2xx stays on the API-error channel. Regenerate; test both behaviors under default and NoThrow.
• F03 — Empty union marker leaks ArgumentException, loses raw body · CONFIRMED · high · all seven unions, both adapter paths. {"_tag":""} misses the known-tag map, hits ArgumentException.ThrowIfNullOrEmpty(tag) in UnknownOpenCodeError (Models/UnknownOpenCodeError.cs:19); ReadTolerantError catches only JsonException (ResponseAdapter.cs:93-96) → BCL exception escapes even under NoThrow, RawBody dropped. Same for a 200 payload with "type":"". Contradicts ADR-0009 tolerance. Fix: generated converters classify empty/whitespace markers as malformed → JsonException; adapter catches then yield null error + raw body (non-2xx) or OpenCodeTransportException (malformed success). Keep public ctor guards. Tests across representative unions, both paths.
• F03-fold / R4 — centralize unknown-carrier construction: ResponseAdapter.Downgrade (ResponseAdapter.cs:99-103) and generated OpenCodeErrorJsonConverter (:53) build the carrier independently — fold a shared runtime factory into the F03 fix to kill carrier-shape drift (UNVERIFIED-FINDER R4; do it because the F03 fix touches both sites anyway).
• F04 — Dot-segment ids silently rewrite the request path · CONFIRMED · medium · every generated path parameter. Uri.EscapeDataString leaves ./.. unescaped (OpenCodeRoutes.cs:35-39); new Uri(base + route) (Pipeline.cs:87) removes dot segments. Verified: session id .. → /api/session/../message/m1 collapses to /api/message/m1; message id .. → /api/session/s/. Fix: generator-owned route-segment guard rejects exact . and .. (decide whitespace-only too) before URI construction. Tests inspect actual outgoing RequestUri for both parameter positions. Do not fight System.Uri canonicalization without cross-TFM proof.
• F06 — Undefined ErrorBehavior silently acquires NoThrow semantics · CONFIRMED · low · public options. Pipeline.cs:96-98 tests is ErrorBehavior.Default; (ErrorBehavior)2 suppresses the throw. Fix: exhaustive branch — Default throws on error, NoThrow returns, anything else ArgumentOutOfRangeException. Undefined-value test.
• F12 — Send-path ObjectDisposedException can escape under a disposal race · PLAUSIBLE · low. SendCoreAsync (Pipeline.cs:125-137) catches only HttpRequestException while ReadBodyAsync wraps ODE. Fix: add ODE to the send-path filtered catch (keep OperationCanceledException passing through; pre-send disposed guard stays outside the catch). Deterministic handler-level ODE test.

Notes

• Public API names untouched — no baseline churn expected; if a fix forces a baseline change, stop and return to the maintainer.
• Full verifier text lived in .scratchpad/ultra-review/VERIFICATION-REPORT.md (ephemeral); the mechanisms above are the preserved record.