cc-ci/BACKLOG-dstamp.md

BACKLOG — phase dstamp

Build backlog (Builder-owned)

• Read phase plan + plan.md §6.1/§7/§9 + Adversary prep notes + stamp-relevant harness code.
• Establish abra's chaos-version mechanism from abra source @06a57de (= pinned binary).
• Rule out abra-version drift (constant store path since nixos system-4, 2026-06-01).
• 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.
• Timeline: run 184 (06-05, solo) green @7ae7b0f; clustered 06-10/06-11 runs drift @ same ref.
• Identify shared-stack collision vector (app_domain = hash(recipe|pr|ref); upgrade chaos_redeploy bypasses app-domain flock).
• Isolated real runs (repro1–4) + direct UpdateStatus/PreviousSpec capture → root cause attributed.
• 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).
• 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).
• 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

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.