shellchecker

#!/usr/bin/env bash


# Shebang wrapper runs script if 'shellcheck' returns no errors
# Copyright (C) 2020 S0AndS0
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published
# by the Free Software Foundation, version 3 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.


__usage__() {
    local _message="${1}"
    cat <<'EOF'
Shebang wrapper runs script if 'shellcheck' returns no errors


Options for `shellcheck` may be defined prior to shell name...

    #!/usr/local/sbin/shellchecker --format=gcc bash


Options for named shell may be defined after shell name...

    #!/usr/local/sbin/shellchecker bash --restricted


Example script...

    #!/usr/local/sbin/shellchecker --format=gcc bash --restricted

    _argument_list=("${@}")
    for i in "${!_argument_list[@]}"; do
        printf '_argument_list[%i] -> %s\n' "${i}" "${_argument_list[${i}]}"
    done
EOF

    if ((${#_message})); then
        printf >&2 '\n\nError: %s\n' "${_message}"
        exit 1
    fi
}


_argument_list=("$@")
read -ra _checker_shell_list <<<"${_argument_list[0]}"
for i in "${!_checker_shell_list[@]}"; do
    _element="${_checker_shell_list[${i}]}"
    [[ "${_element}" =~ ^(bash|dash|ksh|sh)$ ]] && {
        _shell_name="${_element}"
        _slice_index_checker="${i}"
        _slice_index_shell="$((i + 1))"
        break
    }
done

((${#_shell_name})) || {
    __usage__ 'Shell name undefined!'
}

_checker_opts=("${_checker_shell_list[@]::${_slice_index_checker}}")
_shell_opts=("${_checker_shell_list[@]:${_slice_index_shell}}")


for i in "${!_argument_list[@]}"; do
    [[ "${i}" == 0 ]] && {
        continue
    }

    _element="${_argument_list[${i}]}"
    [[ -x "${_element}" ]] && {
        _script_path="${_element}"
        _script_opts=("${_argument_list[@]:$((i + 1))}")
        break
    }
done


((${#_checker_opts[@]})) || ((${#_shell_opts[@]})) && {
    ## Ensure shell is configured for shellcheck
    grep -q "\<${_shell_name}\>" <<<"${_checker_opts[@]}" || {
        _checker_opts+=( -s "${_shell_name}" )
    }

    ## Ensure that shebang errors are excluded
    grep -q "\<2096\>" <<<"${_checker_opts[@]}" || {
        for i in "${!_checker_opts[@]}"; do
            _element="${_checker_opts[${i}]}"
            if [[ "${_element}" == '-e' ]]; then
                _next_element="${_checker_opts[$((i + 1))]}"
                _checker_opts[${i} + 1]="${_next_element},2096"
                _exclude_matched=1
                break
            elif [[ "${_element}" =~ --exclude* ]]; then
                _checker_opts[${i}]="${_element},2096"
                _exclude_matched=1
                break
            fi
        done

        ((_exclude_matched)) || {
            _checker_opts+=( -e 2096 )
        }
    }
}


((${#_script_path})) || {
    __usage__ 'Script path undefined!'
}

[[ -x "${_script_path}" ]] || {
    __usage__ "Script path not executable -> '${_script_path}'"
}


((SHELLCHECKER_VERBOSE)) && {
    printf >&2 '# shellchecker -> shellcheck "%s" "%s"\n' "${_checker_opts[*]}" "${_script_path}"
}
shellcheck "${_checker_opts[@]}" "${_script_path:?'No script found'}" && {
    ((SHELLCHECKER_VERBOSE)) && {
        printf >&2 '# shellchecker -> %s "%s" "%s"\\\n' "${_shell_name}" "${_shell_opts[*]}" "${_script_path}"
        printf >&2 '#                 %s\\\n' "${_script_opts[@]}"
    }
    ${_shell_name} "${_shell_opts[@]}" "${_script_path}" "${_script_opts[@]}"
}