cc-ci/BACKLOG-dstamp.md

# BACKLOG — phase `dstamp`

## Build backlog (Builder-owned)

- [x] Read phase plan + plan.md §6.1/§7/§9 + Adversary prep notes + stamp-relevant harness code.
- [x] Establish abra's chaos-version mechanism from abra source @06a57de (= pinned binary).
- [x] Rule out abra-version drift (constant store path since nixos system-4, 2026-06-01).
- [x] Minimal reproductions of the git/abra chaos-version path (cp-a; go-git base; mirror-faithful)
      — all stamp the CORRECT head 7ae7b0f7, NO drift in current host state.
- [x] Timeline: run 184 (06-05, solo) green @7ae7b0f; clustered 06-10/06-11 runs drift @ same ref.
- [x] Identify shared-stack collision vector (`app_domain` = hash(recipe|pr|ref); upgrade
      chaos_redeploy bypasses app-domain flock).
- [x] Isolated real runs (repro1–4) + direct UpdateStatus/PreviousSpec capture → root cause attributed.
- [x] Concurrency REFUTED (solo repro1/4 reproduce). Mechanism = swarm `failure_action:rollback`
      reverts the chaos-version label (direct evidence repro4: Spec=7ae7b0f7+U→PreviousSpec=eb96de9+U).
- [x] 06-05→06-10 change = rcust-phase heavier resident host load → start-first new task reliably OOMs → rollback every run (solo 06-05 run 184 didn't; my repro2 didn't either).
- [x] Blast-radius: only discourse affected (keycloak/n8n have the policy but upgrade PASS L4 across runs; drone/traefik infra). General harness guard covers all.
- [ ] Restore discourse to its true level in real CI via the drone `!testme` path (M2) — fix1 PASS (install,upgrade); need reliability reruns + full all-stages + !testme.
- [ ] Prove HC1 still has teeth (a deliberately wrong stamp still FAILs).
- [ ] Close the DEFERRED.md dstamp re-entry with pointers.

## Adversary findings
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**Root cause independently confirmed @2026-06-11T17:3x (JOURNAL not read, anti-anchoring preserved):**

Docker Swarm `failure_action: rollback` + `order: start-first` in discourse's `compose.yml` app
service (BOTH `eb96de94` base AND `7ae7b0f` PR-head). On the upgrade chaos redeploy, `start-first`
runs OLD + NEW tasks co-resident (~2× memory); the heavy Rails/precompile app fails swarm's 5s
update monitor under host memory pressure → rollback fires → app service spec reverts to
PreviousSpec (`chaos-version=eb96de94+U`). Because `start-first` kept the OLD task serving,
`wait_healthy` passed; `deployed_identity` read the rolled-back spec; HC1 misreported it as
"stamp mismatch" (the real failure was "new task failed the update monitor").

`services_converged` blind spot: `"rollback_completed"` not in blocking states → returned True.

Evidence: `docker service inspect disc-ae10f0_..._app` confirmed `UpdateConfig: {On failure:
rollback, Order: start-first, Monitoring Period: 5s}`. repro1 (isolated, no concurrency) ALSO
showed drift → pure-concurrency hypothesis REFUTED independently before reading Builder evidence.

abra exonerated: abra reads `git HEAD = 7ae7b0f` and stamps `7ae7b0f7+U` CORRECTLY. Three
bail-at-secrets repros + repro2 debug line confirm. The `+U` comes from `compose.ccci.yml` as
untracked file in per-run recipe dir (rcust-era overlay absent from run 184's pre-rcust path).

Fix 0cc31a5 assessed CORRECT: overlay sets `order: stop-first` (eliminates OOM 2×-memory
trigger); `lifecycle.assert_upgrade_converged` closes the wait_healthy blind spot by catching
`"rollback_completed"|"rollback_paused"|"paused"` and failing HONESTLY. HC1 unchanged.
Minor race window in `assert_upgrade_converged` (first poll could see "none" before Docker
starts the roll) is covered: with stop-first, a post-race rollback also fails `wait_healthy`.
No blocker. Formal verdict awaits Builder's `claim(dstamp)` commit.