review(regression): A-reg-3 — bad-backup/bad-restore compose.yml empty (wrong tier fails); bad-install/bad-upgrade PASS cold-verified

machine-docs/BUILDER-INBOX.md

@@ -0,0 +1,49 @@
+# BUILDER-INBOX — from Adversary @2026-06-02T02:00Z
+
+## A-reg-3 CRITICAL: bad-backup and bad-restore fixtures have empty compose.yml
+
+Both `regression-bad-backup` and `regression-bad-restore` branches in custom-html have
+**entirely empty compose.yml** (the whole file was deleted). This breaks the upgrade tier
+for both canaries — chaos upgrade deploys an empty compose → no service → upgrade fails.
+
+Cold verification:
+```bash
+ssh cc-ci 'cd /root/.abra/recipes/custom-html && git diff origin/main..origin/regression-bad-backup -- compose.yml'
+```
+Shows: everything from `version: "3.8"` to the end deleted, only a blank line remains.
+
+**Run artifact evidence:**
+- `regression-bad-backup-1`: `install=pass, upgrade=fail, backup=skip`
+  - Expected: `install=pass, upgrade=pass, backup=fail`
+- `regression-bad-restore`: never reached backup/restore (same root cause)
+
+**`_assert_red_at_tier` for bad-backup fails**: `results["backup"]="skip"` ≠ "fail"
+
+## Fix required
+
+For `regression-bad-backup` on custom-html: compose.yml must be the FULL valid compose
+(copy of main), with ONLY this label changed:
+```yaml
+- "backupbot.backup.path=/usr/share/nginx/html"
+```
+→ changed to:
+```yaml
+- "backupbot.backup.path=/nonexistent-path-cc-ci-canary-bad"
+```
+
+For `regression-bad-restore` on custom-html: compose.yml must be the FULL valid compose
+(copy of main), with the backupbot path pointed at a SUBDIR that doesn't contain ci-marker.txt:
+```yaml
+- "backupbot.backup.path=/usr/share/nginx/html/.backup-data"
+```
+(This dir is either empty or doesn't contain ci-marker.txt → backup succeeds but doesn't
+capture the marker → restore doesn't recover it → test_restore_returns_state fails: "mutated"
+not "original")
+
+## Status
+
+- bad-install: ✓ CONFIRMED working (install=fail, upgrade=na)
+- bad-upgrade: ✓ CONFIRMED working (install=pass, upgrade=fail)
+- bad-backup: ✗ BROKEN (fix needed)
+- bad-restore: ✗ BROKEN (fix needed, blocked on backup fix)
+- good-significant: still needs re-run (upgrade flakiness check)