#!/bin/sh
# script/lint: run the linter. golangci-lint is never installed locally: it
# runs via docker only, one way, everywhere — script/lint builds
# Dockerfile.lint, which COPYs the repo into the pinned golangci-lint image
# and lints as a build step. This works even when the docker daemon is remote
# and bind mounts are impossible, and it removes the host linter's shared
# cache, which has attributed other checkouts' findings to this one.
#
# --no-cache-filter=lint forces the lint stage to re-execute on every run; a
# cached lint stage exits 0 in under a second having linted nothing. The deps
# stage keeps its cache, so module downloads are not repeated.
# --progress=plain keeps the linter's own output visible on success, so a
# passing run shows the issue count rather than nothing.
# --output=type=cacheonly leaves no image behind to clean up.
#
# docker silently ignores --no-cache-filter for a stage name that does not
# match, so a rename or a typo would restore the cached false green with no
# warning and a fast exit 0. The flag is therefore not trusted: the build
# output is teed to a log and a run is only a pass if golangci-lint's own
# summary line ("N issues." / "N issues:") is in it. No summary, no lint,
# whatever the exit code says.
set -eu

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

main() {
    cd "$ROOT"

    log="$(mktemp -t webhooker-lint.XXXXXXXX)"
    rcfile="$(mktemp -t webhooker-lint-rc.XXXXXXXX)"
    trap 'rm -f "$log" "$rcfile"' EXIT INT TERM

    # The pipeline's status is tee's, and POSIX sh has no pipefail, so the
    # build's status travels via a file. Output still streams live.
    {
        docker build \
            -f Dockerfile.lint \
            --no-cache-filter=lint \
            --progress=plain \
            --output=type=cacheonly \
            . 2>&1 && echo 0 >"$rcfile" || echo $? >"$rcfile"
    } | tee "$log" >&2

    rc="$(cat "$rcfile")"
    [ "$rc" -eq 0 ] || exit "$rc"

    if ! grep -qE '[0-9]+ issues[.:]' "$log"; then
        echo "script/lint: golangci-lint printed no summary line; the linter" >&2
        echo "  did not run. Check that the stage named in --no-cache-filter" >&2
        echo "  still matches a stage in Dockerfile.lint." >&2
        exit 1
    fi
}

main "$@"