git-rpm-version-gen

#! /usr/bin/env bash

# Copyright (C) 2018 Quickhatch
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

# This script is derived from git-version-gen from Gnulib:
# https://git.savannah.gnu.org/cgit/gnulib.git/tree/build-aux/git-version-gen
# It may be run two ways:
# - from a git repository in which the "git describe" command below produces
#   useful output (thus requiring at least one signed tag)
# - from a non-git-repo directory containing a .tarball-rpm-version file, which
#   presumes this script is invoked like
#   "./git-rpm-version-gen .tarball-rpm-version".

# In order to use snapshot release RPM version/release strings in your project,
# you will need a generated version/release string file:
#
# .tarball-rpm-version - present only in a distribution tarball, and not in a
#   checked-out repository.  Created with contents that were learned at the last
#   time autoconf was run, and used by git-rpm-version-gen.  Must not be present
#   in either $(srcdir) or $(builddir) for git-rpm-version-gen to give accurate
#   answers during normal development with a checked out tree, but must be
#   present in a tarball when there is no version control system.  Therefore, it
#   cannot be used in any dependencies.  GNUmakefile has hooks to force a
#   reconfigure at distribution time to get the value correct, without penalizing
#   normal development with extra reconfigures.
#
# .tarball-rpm-version is never generated in a VC'd directory, so it need not
# be listed in .gitignore.
#
# Use the following line in your configure.ac, so that $(QH_RPM_VERSION) and
# $(QH_RPM_RELEASE), or alternate variables of your choice, will automatically
# be up-to-date each time configure is run.
#
# QH_RPM_VERSION_RELEASE(
#         m4_esyscmd_s([build-aux/git-rpm-version-gen .tarball-rpm-version]))
#
# You will also want to distribute git-rpm-version-gen, so that it is
# available when autoreconf runs. If you use Automake, you can do this with
# AC_REQUIRE_AUX_FILE([git-rpm-version-gen]) or by adding the file to
# EXTRA_DIST IN Makefile.am.
#
# Then use the following lines in your Makefile.am, so that
# .tarball-rpm-version will exist in distribution tarballs.
#
# dist-hook:
#	echo $(QH_RPM_VERSION) $(QH_RPM_RELEASE) > $(distdir)/.tarball-rpm-version

function usage()
{
	cat <<- EOF

	Usage: $me [OPTION]... .tarball-rpm-version

	Print RPM Version and Release tags. The format of .tarball-rpm-version
	is a single line containing the version and release strings separated
	by whitespace. For example:

	1.2.3 4.20180226gitdeadbee

	If this file is not present, or contains corrupt data, the script will
	attempt to use git to determine version and release strings which follow
	Fedora guidelines (https://fedoraproject.org/wiki/Packaging:Versioning).
	If that fails, the fallback version and release strings will be used.
	The result will be emitted to standard output.

	Options:

	  -p, --prefix PREFIX			prefix of git release tags (default: $PREFIX)
	  -v, --version-fallback FALLBACK	fallback version tag (default: $VERSION_FALLBACK)
	  -r, --release-fallback FALLBACK	fallback release tag (default: $RELEASE_FALLBACK)
	  -h, --help				display this help and exit
	EOF
} # usage

# borrowed from gnulib
# msgf_ FORMAT-STRING ARG1...
function msgf_ ()
{
  local msgf_format_="$1"
  shift
  local nl='
'
  case $* in
    *$nl*) me_=$(printf "$me"|tr "$nl|" '??')
       printf "$msgf_format_" "$@" | sed "s|^|$me_: |" ;;
    *) printf "$me: $msgf_format_" "$@" ;;
  esac
} # msgf_

# borrowed from gnulib
# msg_ WORD1...
function msg_ ()
{
  # If IFS does not start with ' ', set it and emit the message in a subshell.
  case $IFS in
    ' '*) msgf_ '%s\n' "$*";;
    *)    (IFS=' '; msg_ "$@");;
  esac
} # msg_

# borrowed from gnulib
# warn_ WORD1...
function warn_ ()
{
  msg_ "$@" 1>&2
} # warn_

# borrowed from gnulib
# die WORD1...
function die()
{
  warn_ "$@"
  exit 1
} # die

me=$(basename $0)
nl='
'
PREFIX=v
prefix=$PREFIX
RELEASE_FALLBACK=1
release_fallback=$RELEASE_FALLBACK
VERSION_FALLBACK=0
version_fallback=$VERSION_FALLBACK
vr=

short_opts='hp:r:v:'
long_opts='help,prefix:,release-fallback:,version-fallback:'

if ! options=$(getopt --options $short_opts --longoptions $long_opts --name $me -- "$@"); then
  die "Option parsing failed"
fi
eval set -- "$options"

while true; do
  case "$1" in
    -h|--help) usage; exit ;;
    -p|--prefix) prefix="$2"; shift 2 ;;
    -r|--release-fallback) release_fallback="$2"; shift 2 ;;
    -v|--version-fallback) version_fallback="$2"; shift 2 ;;
    --) shift; break ;;
    *) die 'Option parsing failed' ;;
  esac
done

vr_file=$1

test "x$vr_file" != x || die 'version file argument is required'

# first try the version/release file
if [[ -f $vr_file ]]; then
  vr=$(<$vr_file) || vr=
  # there should be two strings
  test "$(wc -w <$vr_file)" = 2 || vr=
  # reject multi-line output
  case $vr in
    *$nl*) vr= ;;
  esac
  # version and release should start with a number
  for w in $vr; do
    case $w in
      [0-9]*) ;;
      *) vr= ;;
    esac
  done
  test "x$vr" = x \
    && warn_ "WARNING: $vr_file contains invalid or corrupt data"
fi

# if the file above produced a version use that, otherwise try git, and if
# that fails use the fallback version/release
if test "x$vr" != x; then
  : # use $vr
elif test "$(git log --max-count=1 --pretty=format:x . 2>&1)" = x \
    && gv=$(git describe --match="$prefix*" HEAD 2>/dev/null) \
    && case $gv in
         $prefix[0-9]*) ;;
         *) (exit 1) ;;
       esac; then

  # version tag
  version=$(sed -re "s/^$prefix([0-9][0-9.]*).*$/\1/" <<<$gv)

  # release tag
  if git describe --exact-match --match="$prefix*" HEAD &>/dev/null; then

    # this version is a release; git describe data won't have a commit count to
    # use for package release number, so we use fallback release tag instead.
    pkgrel="$release_fallback"

  else # snapshot release

    # get package release number from git describe data
    pkgrel=$(sed -re "s/^.*-([0-9]{1,})-g.*$/\1/" <<<$gv)

    # snapinfo component
    commit=$(git log --max-count=1 --format=%h HEAD)
    date=$(git log --max-count=1 --format=%cd --date=format:%Y%m%d HEAD)
    snapinfo=".${date}git${commit}"

  fi

  # use the extraver component of the release tag to indicate that the
  # repository state is "dirty"
  git update-index -q --refresh &>/dev/null
  dirty=$(git diff-index --name-only HEAD)
  test "x$dirty" != x && extraver='.dirty'

  release=${pkgrel}${extraver}${snapinfo}

  vr="$version $release"
else
  vr="$version_fallback $release_fallback"
fi

printf '%s\n' "$vr"