docs(tasks): review-001 response-decode fidelity (FWD-07/08/10/12) complete

tasks/adapters/review-001-response-decode-fidelity.md

@@ -1,7 +1,7 @@
 ---
 id: review-001-forward-response-fidelity
 name: Upstream response decode — vendored JSON, size caps, loud auth errors, error bodies (FWD-07, FWD-08, FWD-10, FWD-12)
-status: pending
+status: completed
 depends_on: []
 scope: moderate
 risk: medium
@@ -44,14 +44,14 @@ Review 001 findings on `src/adapters/forward.rs`'s response-decode paths
 
 ## Acceptance Criteria
 
-- [ ] `application/vnd.api+json` (and `application/problem+json`) decode as JSON, not byte arrays (test)
-- [ ] Response size cap enforced on JSON/text/binary read paths (test)
-- [ ] Non-SSE content-type on a Sub op produces a loud error, not an empty stream (test)
-- [ ] Invalid credential values fail loudly at call time (test), no credential material logged
-- [ ] Upstream 4xx/5xx bodies surface bounded in the error envelope (test)
-- [ ] Duplicate `value_to_*` helpers collapsed; `text/` buffering branch removed or safe; reload atomic
-- [ ] `forward.rs` COV-01 uncovered regions (binary branch, auth arms, non-2xx mapping, content-type branches) substantially covered
-- [ ] `cargo test` and `cargo clippy --all-targets -- -D warnings` pass
+- [x] `application/vnd.api+json` (and `application/problem+json`) decode as JSON, not byte arrays (test)
+- [x] Response size cap enforced on JSON/text/binary read paths (test)
+- [x] Non-SSE content-type on a Sub op produces a loud error, not an empty stream (test)
+- [x] Invalid credential values fail loudly at call time (test), no credential material logged
+- [x] Upstream 4xx/5xx bodies surface bounded in the error envelope (test)
+- [x] Duplicate `value_to_*` helpers collapsed; `text/` buffering branch removed or safe; reload atomic
+- [x] `forward.rs` COV-01 uncovered regions (binary branch, auth arms, non-2xx mapping, content-type branches) substantially covered
+- [x] `cargo test` and `cargo clippy --all-targets -- -D warnings` pass
 
 ## References
 
@@ -63,6 +63,57 @@ Review 001 findings on `src/adapters/forward.rs`'s response-decode paths
 > review-001-forward-url-safety (request side) and
 > review-001-sse-parser — sequence those first or coordinate.
 
+FWD-07: JSON dispatch is now mime-essence based
+(`is_json_content_type`: type `application`, subtype `json` or `+json`
+suffix; hand-rolled — `mime` is in the lock file only as a transitive
+dep of reqwest, not a direct dependency, so no new crate). Read paths
+(JSON/text/binary) are byte-capped by `read_body_capped` at
+`RESPONSE_BODY_CAP` = 16 MiB; over-cap surfaces `HTTP_413`.
+`forward_stream` checks the `Content-Type` essence (`text/event-stream`)
+and a non-SSE 2xx yields one `INVALID_RESPONSE_TYPE` error envelope
+instead of an empty stream. FWD-08: every silently-dropped header —
+default headers (`build_request`), and the Bearer/ApiKey/Basic
+credential arms — now returns a loud `CallError::internal` ("refusing
+to send the request unauthenticated"); error text names the header or
+namespace but never echoes credential material (tested). FWD-10:
+non-2xx in both `forward` and `forward_stream` goes through
+`error_envelope`: `HTTP_<status>` mapping unchanged (ADR-023) plus a
+bounded echo of the upstream body — read once, capped at
+`ERROR_BODY_ECHO_CAP` = 4 KiB, control characters stripped (newline/tab
+kept), `[truncated]` marker when the read hit `STATUS_BODY_DRAIN`
+(64 KiB) without EOF, in which case the connection is dropped rather
+than drained further (bounded connection-reuse trade). FWD-12:
+`value_to_path_segment`/`value_to_query` collapsed onto one
+`scalar_value_to_string` extractor (the raw scalar is shared; path
+rendering applies `PATH_VALUE_ENCODE_SET`, query emission stays raw for
+`query_pairs_mut` — they were byte-identical pre-FWD-01 but the roles
+diverged, so a single raw-then-encode function was wrong for the query
+arm and the pre-existing `+`-encoding test proved it); `forward` lost
+its `op_type` parameter (the Sub branch only toggled ACCEPT and the
+`text/` buffering branch is gone — Sub ops route through
+`forward_stream`); request-body serialization failure is a loud
+`CallError::internal` instead of a silent `null` body (both handlers);
+`SharedHttpClient` now holds client+config in one
+`ArcSwap<SharedHttpInner>` so `reload` swaps both in a single atomic
+store (minimal touch to `src/client/http_client.rs`, public API
+`client()`/`config()` unchanged). COV-01 regions covered: vendor/`+json`
+content-type branches, binary branch, all three auth arms (loud error
+paths + the pre-existing success tests), non-2xx mapping with error-body
+echo (2/404/429/500, truncated and exact), cap trips on all three read
+paths, non-SSE Sub stream, SSE happy path through `forward_stream`.
+
 ## Summary
 
-> Filled on completion.
+FWD-07/08/10/12 remediated in `src/adapters/forward.rs` (+
+one-spot `SharedHttpClient::reload` atomicity fix in
+`src/client/http_client.rs`): vendor-JSON mime-essence decode, 16 MiB
+`RESPONSE_BODY_CAP` on all buffered reads (`HTTP_413` on breach),
+loud `INVALID_RESPONSE_TYPE` on non-SSE Sub-op streams, loud call-time
+errors for invalid credential/default-header values (no secret echo),
+bounded 4 KiB error-body echo on non-2xx with a 64 KiB
+`STATUS_BODY_DRAIN` read cap, duplicate scalar helpers collapsed,
+`forward`'s dead `op_type` Sub branch removed, serialization failure
+made loud, and the hot-reload swap made atomic (joint client+config
+holder). 23 tests in `forward.rs::tests` (was 9) covering the previously
+uncovered binary/auth/non-2xx/content-type regions (COV-01); full
+suite 265 passing. Commits 9bb8487 (core) and 7ac2dc5 (tests).