#!/bin/sh
# script/lint: run the linter. golangci-lint is never installed on a
# host: this builds Dockerfile.lint, which copies the repo into the
# digest-pinned golangci-lint image and lints as a build step, so a
# successful build is a clean lint. A cold cache needs the network to
# pull the image and for `go mod download`; once warm this runs offline
# until go.mod or go.sum changes.
#
# Without a fresh CHECK_EPOCH docker serves the gate layers from cache
# on an unchanged tree and this exits 0 having run no linter. The PID is
# in the value because two lint runs land inside the same second easily.
#
# The image is never used, so --output=type=cacheonly writes none;
# without it every run leaves an untagged image behind.
set -eu

ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"

main() {
    cd "$ROOT"
    docker build \
        --build-arg CHECK_EPOCH="$(date +%s)-$$" \
        --output=type=cacheonly \
        -f Dockerfile.lint \
        .
}

main "$@"