script/cibuild was a plain `docker build .`, and the Dockerfile does
`COPY . .` followed by `RUN make check`. Docker invalidates a COPY layer
only when the copied content changes, so on an unchanged tree the check
layer was served from cache, the suite never ran, and the build still
exited 0. Measured here: run 1 took 18.5s and ran the suite; run 2 on a
byte-identical tree took 0.286s with `RUN make check` CACHED.
script/cibuild and script/docker now assign a per-invocation nonce on its
own line and pass it as --build-arg CHECK_EPOCH. The Dockerfile declares
ARG CHECK_EPOCH, guards it with `[ -n "$CHECK_EPOCH" ] || exit 1`, and
expands it into the check command. Post-fix, two consecutive runs both
execute make check (17.4s / 8.1s) with `RUN script/bootstrap` still
CACHED, so dependency layers are untouched and the build ceiling is not
at risk.
The guard is what makes a bare `docker build .` — the command
REPO_POLICIES named verbatim — fail closed rather than reuse the empty
and therefore stable cache key; verified failing in 0.455s. Holding the
epoch constant restores the false green (run 2 fully CACHED), which pins
the varying value as the operative mechanism rather than a coincidence.
Because the guard references $CHECK_EPOCH it is itself value-keyed:
BuildKit renders the epoch into that layer's description and re-runs the
layer when the value changes. Each stage therefore has two independent
invalidation points, the guard and the expansion, and the guard always
precedes the check RUN. Both are kept and the prose now records this;
the expansion remains defence in depth and is what puts the epoch in the
build log.
The false guarantee was org-canonical text in more than one document, so
it is corrected everywhere it appeared rather than only where the issue
first found it. REPO_POLICIES.md carried it in two places, and its Go
multistage template had check steps in two stages; ARG is stage-scoped,
so both stages get the treatment or the fleet inherits the half-fixed
shape. CODE_STYLEGUIDE_GO.md restated the guarantee for the bare command
this change makes fail closed. NEW_REPO_CHECKLIST.md specified the
pre-fix script/cibuild verbatim, so every new repo would have been born
with the false green, and EXISTING_REPO_CHECKLIST.md ended on a
`docker build` acceptance item that the guard makes unsatisfiable by
design — an agent working that checklist would have been led to delete
the guard to tick the last box. Both checklists' Dockerfile criteria were
also satisfiable by a Dockerfile whose check layers are still frozen, and
now require the ARG and guard in every check-running stage.
REPO_POLICIES.md's own Dockerfile criterion carried that same incomplete
form; it is tightened by cross-reference to the CHECK_EPOCH rule rather
than by duplicating the canonical block. The Go template's Key points
gain a caveat that the cache-bust turns the `COPY --from=lint` no-op into
a content-cache hit, so a repo using a file-dependency trick for stage
ordering must re-prove that ordering on a warm cache after adopting it.
That was re-proved in another repo in the org which uses the trick with a
marker file, where the ordering held; the caveat states explicitly that
it was not verified here, this repo being single-stage with no lint stage
to order against.
Split quickstart into separate repo-policy and code-style passes, clone
prompts repo once instead of per-command, and make each prompt
self-contained so agents don't need memory of prior runs.
- Move title and last_modified to YAML front matter (all policy docs)
- Make all document sections H1, subsections H2
- Update version rule to reference front matter format
- Fix "our" → "your" typo in Go styleguide
- Fix Python styleguide numbering (2. → 1.)
- Fix README: "flat collection" → accurate description, remove stale TODO
- Remove Makefile items from code styleguides (repo stuff, not code),
add note linking to Repository Policies
- Change zerolog → slog in Go styleguide
- Fix JS styleguide npm reference: both work, but use make targets
- Drop .json from healthcheck path, add JSON content-type requirement
- Add Author/License to Go HTTP Server Conventions
- Convert hyperlinks to backtick URLs in checklists for consistency
- Add version/front matter to both checklists
Add .gitignore, LICENSE (MIT), Makefile, Dockerfile, .dockerignore,
and pin prettier via yarn lockfile for integrity-checked markdown
formatting. Update REPO_POLICIES.md self-reference to point to this
repo. Format markdown files with prettier.
