---
id: review-002-fwd15-stream-timeout
name: Subscriptions must not inherit the 30s total request timeout (FWD-15) + stream byte cap (FWD-14)
status: completed
depends_on: []
scope: moderate
risk: medium
impact: component
level: implementation
tags: [client, review-002, adapters]
---

## Description

Review 002 FWD-15 [major] + FWD-14. Two streaming-path defects, same
code region (`src/adapters/forward.rs:824-934`):

1. **FWD-15**: `forward_stream` sends through the shared client whose
   `DEFAULT_REQUEST_TIMEOUT` is 30 s — verified against reqwest 0.13.4
   that the total-timeout sleep rides into the response body stream.
   A healthy subscription dies at 30 s with `SSE stream error:
   operation timed out` — even keep-alive-emitting sources (the
   gateway deliberately runs subscriptions unbounded per ADR-021;
   dispatch.rs:28). The outbound half of the same subscription is
   mortally capped.
2. **FWD-14**: the streaming branch has no size accounting — the 1 MiB
   cap bounds a single SSE *line*, not the stream. A hostile upstream
   emits well-formed 1-MiB-line events forever: 30 s of those is
   ~GB/s into envelope allocation (mitigated only by the timeout —
   which FWD-15's fix then removes, so **both must land together or
   the fix makes FWD-14 worse**).

## Acceptance Criteria

- [ ] FWD-15: `HandlerKind::Stream` forwards send with
      `request_timeout: None` while keeping connect + read timeouts
      (implementer's choice: per-request extension override verified
      against reqwest 0.13, or a second derived client built from the
      same config minus the total timeout) — a >30 s healthy
      subscription survives
- [ ] FWD-15 wire test: responder trickling `: keepalive` comments past
      30 s (scaled: use a configurable short client timeout in the
      test) → stream still delivering events after the old deadline
- [ ] FWD-14: a total byte cap on the streaming path (accumulate
      across `feed`; per-subscription total, default documented) and
      the line-cap check moved to *before* `extend_from_slice` so the
      overshoot cannot exceed cap + one chunk
- [ ] FWD-14 test: a stream exceeding the total cap terminates with a
      single terminal error envelope (the stream-ends semantics)
- [ ] Cap value + no-timeout decision documented in the module doc and
      http-server.md (ADR-049/021 note: unbounded *time* by design for
      subscriptions, bounded *bytes* per subscription)
- [ ] `cargo test`, `cargo clippy --all-targets -- -D warnings`,
      `cargo fmt --check` pass

## References

- docs/reviews/002-post-remediation-review.md (Part D', FWD-14, FWD-15; Unit 2 rationale)
- src/adapters/forward.rs:824-934 (send + streaming branch), :969-1082 (SSE parser), http_client.rs:69-95/:149-150/:164-178 (timeout config + read-timeout doc claim)
- docs/architecture/decisions/049-streaming-handler-for-subscriptions.md
- tasks/client/review-001-client-timeout-retry.md (the timeout defaults this revises)

## Notes

Order matters **within** this task: land FWD-15 with FWD-14 in the same
commit-series — removing the total timeout without the byte cap opens
an unbounded-memory window. The read-timeout (10/30 s stall guard)
stays: it bounds upstream *staleness*; the doc at http_client.rs:149-150
already correctly describes read-timeout as the stall guard (the total
timeout's "stalled upstream" claim there is the thing being fixed).
Coordinate with review-002-cli01-retry-after-budget (same file) and
review-002-client-policy-wire-tests (which should follow this to test
the new behavior) — sequence those.

## Summary

Derived timeout-less stream client (reqwest 0.13 cannot clear a client total timeout per-request, verified against source) + 1GiB total-bytes cap with pre-extend buffer check; over-cap streams end with one HTTP_413 terminal envelope. Wire tests for both arms.