Make the pinned golangci-lint actually reach the host (closes #28)
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REPO_POLICIES.md now carries the canonical script/bootstrap snippet for Go
repos alongside the .golangci.yml bullet, where the pinned linter version
already lives.

The guard it replaces, `if missing golangci-lint; then go install ...; fi`,
tests PATH presence and never version, so on any already-provisioned machine
the pin is inert and a version bump is a no-op. The Dockerfile installs
unconditionally into a clean image, so CI and local then disagree about what
the linter is: a local `make check` green while `make docker` rejects the same
commit, and a container run surfacing findings the host run cannot see.

Comparing versions alone is not enough. `go install` writes to GOBIN (or
GOPATH/bin) while callers resolve through PATH, so a shadowing binary earlier
in PATH lets the install succeed and change nothing a caller ever sees, while
bootstrap prints success. The canonical form therefore compares the installed
version against the pin, re-resolves through PATH after installing and asserts
the pin, and treats any unparseable --version output as a mismatch so the
failure direction is a redundant install rather than a skipped one.

When the assert fails the diagnosis is derived from the resolved path rather
than asserted: a path outside the install directory is shadowing and the
operator is told to remove it or reorder PATH; a path inside it is not, and
saying so would send them after a fault that does not exist; no resolution at
all means the install directory is simply absent from PATH.

The snippet ends with a call site. Two function definitions and no invocation
are a silent no-op with exactly the shape this change exists to close, and the
adoption instructions say to paste the block verbatim.

The version helper ends in `|| true` so a --version that exits non-zero cannot
kill the script through `set -e` under `set -o pipefail` before the diagnostic
is printed, which the styleguide's bash form would otherwise do.

The policy text states each of those as a requirement rather than leaving them
implicit in the code, records why the commit-pinned `go install` ref satisfies
the hash-pinning rule (a commit hash is not a mutable tag, and the checksum
database verifies the fetch; no repo go.sum is consulted, since `go install
pkg@version` ignores the go.mod in the current directory or any parent), and
requires the pin to be a tagged release commit: an untagged pin yields a
pseudo-version that the parser truncates at the first `-`, so no value of
GOLANGCI_LINT_VERSION derived from what --version prints can ever match.

Verification requires two things the previous round lacked: a negative control
against a shadowing binary, and running the controls against the block as a
consuming repo would adopt it, pasted into a script/bootstrap-shaped file and
executed, rather than sourcing it and calling the function directly.

The node and yarn handling described earlier in the document is untouched.
This commit is contained in:
clawbot
2026-08-09 15:23:50 +00:00
parent 51c394552e
commit be59376522
2 changed files with 168 additions and 0 deletions

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@@ -21,6 +21,14 @@ fmt-check, and commit.
# Completed Steps
- 2026-08-09: Made the pinned golangci-lint actually propagate: REPO_POLICIES.md
now carries the canonical `script/bootstrap` snippet for Go repos, which
installs when the installed version does not match the pin (the old
`if missing` guard tested PATH presence only, so pins were inert on any
provisioned machine and CI silently disagreed with local) and then re-resolves
the binary through `PATH` and fails loudly, naming the shadowing path, when
the install did not take effect — the failure mode the naive
compare-then-install fix leaves behind while reporting success.
- 2026-08-09: Fixed the false green in the canonical CI gate: `script/cibuild`
and `script/docker` now pass a per-invocation `CHECK_EPOCH` nonce, and the
`Dockerfile` (plus the Go multistage template in REPO_POLICIES.md, in both its

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@@ -354,6 +354,166 @@ style conventions are in separate documents:
commit-pinned via
`go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@c0d3ddc9cf3faa61a4e378e879ece580256d76e5`.
- **`script/bootstrap` in Go repos must install the pinned golangci-lint
whenever the installed version does not match the pin — not merely when the
binary is absent — and must then verify the install took effect by
re-resolving the binary through `PATH`.** The presence test
`if missing golangci-lint; then go install "$GOLANGCI_LINT_REF"; fi` is wrong:
it tests `PATH` presence and never version, so on any already-provisioned
machine the pin is inert and a version bump is a no-op. Meanwhile the
Dockerfile installs unconditionally into a clean image, so CI and local
silently disagree about what the linter even is. Observed consequences: a
local `make check` green while `make docker` rejected the same commit with six
`goconst` findings, and a container linter surfacing thirteen findings the
host run missed. A stale host linter does not merely fail to prove the tree is
clean — it hides findings only the container can see. This is a deliberate
departure from the node handling described above, which uses whatever node is
installed: the linter version is the specific thing being held equal between
host and container, so for it, presence is not enough.
Comparing versions is necessary but **not sufficient**, because the obvious
fix also fails green. `go install` writes to `GOBIN` (or `GOPATH/bin`) while
callers resolve `golangci-lint` through `PATH`. If a different binary
shadows it earlier in `PATH`, the install genuinely succeeds and changes
nothing any caller will ever see: bootstrap prints success and the next
`make lint` still runs the stale linter. That is worse than no fix, because
it converts a known-stale toolchain into one everyone believes is pinned.
The canonical form, placed in `script/bootstrap` after Go itself is present:
```sh
# golangci-lint v2.12.2, 2026-05-06. The ref must resolve to a TAGGED
# release; see the note on untagged pins below.
GOLANGCI_LINT_VERSION="2.12.2"
GOLANGCI_LINT_REF="github.com/golangci/golangci-lint/v2/cmd/golangci-lint@c0d3ddc9cf3faa61a4e378e879ece580256d76e5"
# The version golangci-lint reports, resolved the way callers resolve it.
# Prints nothing when the binary is absent, exits non-zero, or prints
# something unparseable: all of those must read as "does not match".
# The trailing `|| true` is required, not tidiness. Under `set -o pipefail`
# a non-zero --version would otherwise propagate out of the pipeline and
# kill the script through `set -e` before the diagnostic below is printed.
golangci_lint_version() {
command -v golangci-lint >/dev/null 2>&1 || return 0
golangci-lint --version 2>/dev/null | head -n 1 |
sed -n 's/.*has version v\{0,1\}\([0-9][0-9.]*\).*/\1/p' || true
}
ensure_golangci_lint() {
if [ "$(golangci_lint_version)" = "$GOLANGCI_LINT_VERSION" ]; then
return 0
fi
echo "bootstrap: installing golangci-lint $GOLANGCI_LINT_VERSION"
go install "$GOLANGCI_LINT_REF"
# go install writes to GOBIN (or GOPATH/bin); callers resolve through
# PATH. Re-resolve through PATH and assert the install took effect.
# `hash -r` is load-bearing: without it a shell that already resolved
# a stale golangci-lint answers from its own lookup cache, and this
# check false-fails with the shadowing message below.
hash -r 2>/dev/null || true
gcl_got="$(golangci_lint_version)"
if [ "$gcl_got" = "$GOLANGCI_LINT_VERSION" ]; then
return 0
fi
gcl_bin="$(go env GOBIN)"
[ -n "$gcl_bin" ] || gcl_bin="$(go env GOPATH)/bin"
gcl_found="$(command -v golangci-lint 2>/dev/null || true)"
echo "bootstrap: installed golangci-lint $GOLANGCI_LINT_VERSION into" \
"$gcl_bin, but that is not what callers will get." >&2
case "$gcl_found" in
"")
echo "bootstrap: PATH resolves no golangci-lint at all." \
"Add $gcl_bin to PATH, then re-run bootstrap." >&2
;;
"$gcl_bin"/*)
echo "bootstrap: PATH resolves $gcl_found, inside that same" \
"directory, reporting version ${gcl_got:-unparseable}." \
"Nothing is shadowing it, so the install itself did not" \
"produce the pinned version: check that" \
"GOLANGCI_LINT_VERSION matches GOLANGCI_LINT_REF." >&2
;;
*)
echo "bootstrap: PATH resolves $gcl_found instead, reporting" \
"version ${gcl_got:-unparseable}. Remove that binary or" \
"put $gcl_bin earlier in PATH, then re-run bootstrap." >&2
;;
esac
exit 1
}
# The definitions above are inert on their own; the call site is part of
# the canonical form. In a script/bootstrap that follows the "define all
# functions, then call main" convention, this line belongs inside main()
# next to the other ensure_* steps.
ensure_golangci_lint
```
Four properties are load-bearing; each guards a failure mode that otherwise
fails green:
- **Compare the installed version against the pin**, never test presence.
This is what makes a version bump propagate to machines that already have
some golangci-lint.
- **After installing, re-resolve the binary the way callers resolve it** —
through `PATH`, not the path `go install` wrote to — and assert
`--version` reports the pin. When it does not, fail non-zero and name the
path `command -v` actually found, the version it reports, and the
directory the install wrote to. That is a condition a human has to fix by
hand, so bootstrap must not print success in it. Use `hash -r` first so
the shell does not answer from its own lookup cache. Diagnose the cause
from the resolved path rather than asserting one: only a path **outside**
the install directory is shadowing. When the resolved path is inside it,
nothing is shadowing and telling the operator to delete that binary or
reorder `PATH` sends them after a fault that does not exist.
- **A mis-parse must fall through to reinstall, never to a false match.**
Absent binary, non-zero exit, empty output, and unrecognised output all
yield an empty string, which compares unequal to the pin. The failure
direction is always a redundant install, never a skipped one.
- **Call it.** Two function definitions with no call site are a silent no-op
that reproduces the original defect exactly: exit 0, nothing installed, no
output, stale linter still resolved.
Keep it POSIX sh: no bashisms, no arrays, no `[[`, no `grep -P`.
**On the hash-pinning rule.** `@c0d3ddc9cf3faa61a4e378e879ece580256d76e5` is
a commit hash, not a server-mutable version tag, and the go command verifies
the fetched module against the checksum database — the mechanism the
hash-pinning rule at the top of this document already names as acceptable
for Go modules. Note that `go install pkg@version` runs in module-aware mode
ignoring the `go.mod` in the current directory or any parent, so no repo
`go.sum` is consulted for this install; the checksum database is what
verifies it. The linter is a bootstrap prerequisite rather than part of any
repo's module graph, which is why the canonical form installs it by
commit-pinned ref instead of declaring it in `go.mod`.
**The pin must be a tagged release commit.** `GOLANGCI_LINT_VERSION` is a
separate string because the ref is a hash and carries no readable version,
so the two must be updated together. It works out to a clean `2.12.2` only
because that commit is the `v2.12.2` tag commit: the go command resolves a
commit query to a semver tag on that commit when one exists, so the built
binary reports `2.12.2`. Pin to an **untagged** commit and the go command
falls back to a pseudo-version — the binary then reports something like
`2.12.3-0.20260506110758-c0d3ddc9cf3f`, and this comparison cannot express
it: the parser above stops at the first `-`, so the value to match would
have to be the truncated numeric prefix `2.12.3`, which is also the number
of a real future release. Setting `GOLANGCI_LINT_VERSION` to the full string
`--version` prints can never match, and bootstrap would then reinstall on
every run and exit 1 blaming a shadowing binary that does not exist. Keep
pins on tagged releases.
**Verifying a change to this logic requires a negative control run in an
environment where a shadowing binary exists earlier in `PATH` than the
install target.** Without that, the control passes against the naive
compare-then-install form as well and therefore proves nothing. Also check
the mis-parse direction by feeding it unparseable `--version` output and
confirming it reinstalls rather than reporting a match.
**Run those controls against the block as a consuming repo would adopt it**
— pasted into a `script/bootstrap`-shaped file that is then executed — not
by sourcing it and invoking the function yourself. Driving the function
directly tests something the artifact does not do, and it is exactly how a
missing call site passes every control while the adopted snippet does
nothing.
- When pinning images or packages by hash, add a comment above the reference
with the version and date (YYYY-MM-DD).