Two independent reviewers (one cross-family) converged on the same defect, and it was the
important one: the preflight WARNED and exited 0 on every answer that was not 200 or 404,
so a missing `curl`, a moved registry or a DNS change would have left it green forever —
"the check could not run" presenting as "the pin is fine", in a script whose own header
disclaimed exactly that. Unknown answers are now retried (3x, 5s) and then FAIL, with
wording kept distinct from the deleted case because the two send an operator to different
places.
Also from the reviews:
* An absent secret does not arrive as an unset variable. `${{ secrets.X }}:${{ secrets.Y }}`
interpolates to ":", a perfectly non-empty and perfectly useless credential, and the
tests covered only the unset shape. Both halves are now required, and the parametrised
test drives the production shape.
* HTTP 200 is not a manifest. A proxy or a login page answers 200 too, so the body is
fetched and matched for `schemaVersion` (a shell `case`, so no jq dependency and no
pipeline that can inject).
* The curl stub ignored `-u` and answered 200 regardless, so deleting the real `-u` would
have left the suite green while the live registry rejected every request. It now 401s an
unauthenticated read, as the registry does.
* The mutation's declared diagnostic changed with the script: now that unknown fails too,
the exit code no longer separates "deleted" from "could not check", so the proof turns on
the message and `expect` says so.
* docs/ci-cd.md: `scan` is no longer the only `docker-build.yml` job on the small lane, so
the tag-push exclusivity claim and the lane membership were both false. Fixed.
* "Immutable" was overstated: `ci-image.yml` tags `rev-parse --short HEAD`, so a dispatch or
a weekly no-cache run at the same HEAD republishes that tag from a rebuilt image. Stated,
along with what the rebuild recovery does NOT restore (mutable bases and apt, so equivalent
rather than bit-identical).
* The recovery recipe left you in a worktree checked out at the pin commit — where the
verify script does not exist, and where the workflow carries the pre-bump pin. It now
keeps `$repo`, returns, and removes the worktree. It also needed BuildKit's `http = true`
caveat: the container driver does not inherit the daemon's insecure-registries.
* The root cause carries its evidentiary limit and its reproduction commands, and says what
to conclude if a pin vanishes after server-management#842 lands (refuted, not re-applied).
* The `ci.required-job-step-execution-markers` carve-out named one container-free job; there
are two now, and the membership is what rots.
* The decision record's `''` YAML escapes leaked into rendered prose; "status, no comment ->
ask" is qualified (a prior positive verdict for the SAME head still satisfies condition
(c)); "exits 1" is "exits non-zero" (usage exits 2, jq its own status, signals 128+n).
refs #772
refs #792
Decisions-Edit: yes
timothy
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