review(5): flag matrix-synapse stale-test status gap

machine-docs/BACKLOG-5.md

@@ -25,6 +25,32 @@ Single-writer: `## Build backlog` = Builder-only; `## Adversary findings` = Adve
 
 ## Adversary findings
 
+### [adversary] A5-4 — `matrix-synapse` stale-test/default path leaves no recipe commit status
+**Status:** OPEN — found 2026-06-01T14:16:00Z; see `REVIEW-5.md`.
+
+On the live V5 stale-test candidate `recipe-maintainers/matrix-synapse` PR `#1`, the PR comments show a
+terminal failed `!testme` result for build `#53` plus the default-mode explanatory stale-test comment,
+but the recipe PR head has **no** `cc-ci/testme` commit status at all. As a result, the helper cannot
+read the verdict back from the PR and poll-only returns `PENDING` even though the PR already shows the
+terminal outcome.
+
+**Cold repro:**
+1. Use `recipe-maintainers/matrix-synapse` PR `#1`, head
+   `21e5d84430bdc52f8fa8aa9a40fa5bda8adf06c0`.
+2. Confirm PR comments include:
+   - failure result comment for build `#53` (`#13872`), and
+   - explanatory stale-test comment (`#13877`).
+3. Run:
+   `POST=0 MAX_WAIT=20 INTERVAL=5 /srv/cc-ci/.claude/skills/recipe-upgrade/testme-on-pr.sh matrix-synapse 1`
+4. Observe:
+   - helper returns `VERDICT=PENDING` and `BUILD=?`;
+   - `GET /repos/recipe-maintainers/matrix-synapse/commits/21e5d84430bdc52f8fa8aa9a40fa5bda8adf06c0/status`
+     returns `{"state":"","total_count":0,"statuses":null}`.
+
+**Impact:** this breaks the Phase-5 requirement that the upgrade tooling read the verdict back from the
+PR on the live stale-test/default path. The comment surface says the run is terminal; the status surface
+still says nothing.
+
 ### [adversary] A5-3 — `POST=1 testme-on-pr.sh` can return a stale prior GREEN on re-runs
 **Status:** CLOSED — re-tested 2026-06-01T03:31:30Z; see `REVIEW-5.md` follow-up entry.
 

machine-docs/REVIEW-5.md

@@ -227,3 +227,43 @@ poll-only probe against the Builder's current V5/V6 sandbox candidate. I did **n
     showed `cc-ci/testme status=success` with target URL `/47`.
 
 **Verdict:** V2's poll-only path still holds on the live `n8n` sandbox PR. No new defect found.
+
+---
+
+## Cold-verify finding — 2026-06-01T14:16:00Z
+
+No `Gate: <Mn> CLAIMED` was pending in `STATUS-5.md`, so I used the idle slot for a fresh cold probe of
+the Builder's current V5 stale-test candidate plus the newly-fixed `lasuite-meet` enrollment. I did
+**not** read `JOURNAL-5.md` before forming this verdict.
+
+### Control probe: `lasuite-meet` enrollment fix still holds
+- Cold-shell invocation:
+  `POST=0 MAX_WAIT=20 INTERVAL=5 /srv/cc-ci/.claude/skills/recipe-upgrade/testme-on-pr.sh lasuite-meet 2`
+- The helper returned:
+  `VERDICT=GREEN`
+  `BUILD=https://drone.ci.commoninternet.net/recipe-maintainers/cc-ci/58`
+- PR comment count stayed unchanged across that call (`4 -> 4`), confirming `POST=0` still polls without
+  re-triggering.
+- `GET /repos/recipe-maintainers/lasuite-meet/commits/2d0c70779e7a87dfc240b69606c7bcff2472d720/status`
+  still shows `cc-ci/testme status=success` with target URL `/58`.
+
+### A5-4: stale-test/default path on `matrix-synapse` leaves no recipe commit status, so poll-only reports `PENDING`
+- Probe target: `recipe-maintainers/matrix-synapse` PR `#1`, head
+  `21e5d84430bdc52f8fa8aa9a40fa5bda8adf06c0`.
+- Cold-shell invocation:
+  `POST=0 MAX_WAIT=20 INTERVAL=5 /srv/cc-ci/.claude/skills/recipe-upgrade/testme-on-pr.sh matrix-synapse 1`
+- The helper returned:
+  `VERDICT=PENDING`
+  `BUILD=?`
+- Live PR comments at verify time show the run has already reached a terminal outcome on the PR:
+  - `#13872` (`2026-06-01T13:48:21Z`):
+    `cc-ci: run for matrix-synapse @ 21e5d844 ❌ failure -> .../53`
+  - `#13877` (`2026-06-01T14:03:04Z`): explanatory stale-test/default-mode comment telling the operator
+    to re-run `/recipe-upgrade matrix-synapse --with-tests`.
+- But the recipe head's combined status endpoint is empty:
+  `GET /repos/recipe-maintainers/matrix-synapse/commits/21e5d84430bdc52f8fa8aa9a40fa5bda8adf06c0/status`
+  returned `{"state":"","total_count":0,"statuses":null}`.
+
+**Verdict:** FAIL for this live V5/V2 intersection. The PR comment surface reflects the terminal
+stale-test result, but the commit-status surface is absent, so `testme-on-pr.sh` cannot read the verdict
+back from the PR and incorrectly reports `PENDING`. Filed as `BACKLOG-5.md` item **A5-4**.