prepare-commit-msg.hook

#!/bin/bash

old_commit_msg="$(cat ${1})"
echo -n "" > "${1}"

# Check for new PKGBUILDs
for path in $(git diff --name-only --cached --diff-filter=A); do
    if [[ "${path}" =~ .*/PKGBUILD$ ]]; then
        (
            source "${path}"
            : ${pkgbase:=${pkgname}}
            echo -e "Initial upload: ${pkgbase} ${epoch:+${epoch}:}${pkgver}-${pkgrel}\n" >> "${1}"
        )
    fi
done

# Check for updated PKGBUILDs
for path in $(git diff --name-only --cached --diff-filter=M); do
    if [[ "${path}" =~ .*/PKGBUILD$ ]]; then
        (
            source "${path}"
            : ${pkgbase:=${pkgname}}
            echo -e "upgpkg: ${pkgbase} ${epoch:+${epoch}:}${pkgver}-${pkgrel}\n" >> "${1}"

            # If the pkgrel is "1" and there is no VCS pkgver function (or there is one, but the git revision is "0"), assume a new version.
            [[ $pkgver =~ .+\.r([0-9]+)\..+ ]]
            [[ "${pkgrel}" = "1" && ( $(type -t pkgver) != "function" || ${BASH_REMATCH[1]} = 0 ) ]] && echo -e "upstream release\n" >> "${1}"
        )
    fi
done

# Check for deleted PKGBUILDs
for path in $(git diff --name-only --cached --diff-filter=D); do
    if [[ "${path}" =~ .*/PKGBUILD$ ]]; then
        echo -e "Deleted package: ${path%/PKGBUILD}\n" >> "${1}"
    fi
done

echo "${old_commit_msg}" >> "${1}"