check-readme

#!/bin/bash
# Check that the README links to all files of interest; a heuristic for keeping
# us honest about documenting the contents of this repo.
set -euo pipefail
shopt -s extglob

delim=$'\x1f' # ASCII unit separator

main() {
    compare | report
}

compare() {
    comm --output-delimiter="$delim" \
        <(files-of-interest | sort) \
        <(relative-links README.md | sort)
}

report() {
    local failed=0

    while IFS="$delim" read -r missing unknown found; do
        if [[ -n $missing ]]; then
            echo "missing link to: $missing" >&2
            : $((failed++))

        elif [[ -n $unknown ]]; then
            echo "link to unknown file: $unknown" >&2
            : $((failed++))

        elif [[ -n $found ]]; then
            echo "found: $found"
        fi
    done

    return "$failed"
}

files-of-interest() {
    git ls-files | grep -vxFf <(files-to-ignore)
}

files-to-ignore() {
    git ls-files \
        .gitignore \
        '**/.gitignore' \
        README.md \
        'images/*' \
        actions/setup-ssh/!(*.yaml|README.md) \
        actions/setup-debugger/!(*.yaml|README.md) \
        actions/shellcheck/!(*.yaml|README.md)
}

relative-links() {
    grep -oP '\[.+?\]\(.+?\)' "$@" | grep -oP '(?<=\()(?!(https?|mailto)://).+?(?=\))'
}

main "$@"