Version script to calculate software version from git tags and current date in format: <major>.<minor>.<patch>-<current-year-2-digits><current-day-of-year>.<commit-hash>[.dirty]

version.sh

#!/usr/bin/env bash
script_version="1.33"

set -e
set -u
set -o pipefail
# set -x

# ==================================================
# This script calculates and prints a software version
# based of git repo in current directory and current time.
#
# Version format:
# <major>.<minor>.<patch>-<current-year-2-digits><current-day-of-year>.<commit-hash>[.dirty]
#
# Examples:
# 19.12.45-19350.82f35c
# 20.2.0-20078.7d92ba
# 20.2.0-20084.7d92ba.dirty
#
# <major> and <minor> are taken from the biggest tag in HEAD ancestor tree
# with name in format:
# ref/tags/epoch/v<major>.<optionally-zero-prepended-minor>
#
# Examples of tag names:
# epoch/v19.11
# epoch/v20.02
#
# <patch> is a number of commits between the Major-Minor tag and HEAD.
#
# <comit-hash> is a HEAD commit hash truncated to 6 left chars.
#
# ".dirty" is added in case git working directory is not clean:
#   untracked files are present or tracked files are modified.
#
# ==================================================

# Settings

dir=.
commit=HEAD
commit_hash_length=6
tag_prefix="epoch/v"
debug_mode=0

# ==================================================
# Parse commmand line

if [[ "${1:-}" == "--help" ]]; then
  echo >&2 "Script version: $script_version"
  echo >&2 "Usage: ./version.sh [--debug] [<directory>]"
  exit 2
fi

if [[ "${1:-}" == "--debug" ]]; then
  debug_mode=1
  shift
fi

if [[ -n "${1:-}" ]]; then
  cd -- "$1"
fi

debug() {
  if [[ "$debug_mode" == "1" ]]; then echo "dbg> $*" >&2; fi
}

dbg_print_var() {
  variable_name="$1"
  debug "$variable_name: ${!variable_name}"
}

# ==================================================

dbg_print_var "script_version"

# Calculate string in format "<last-two-year-digits><day-of-year>"

current_day_string=$(date '+%y%j')

dbg_print_var "current_day_string"

# Find if directory contains changes or untacked files

dirty=""
if [[ $(git -C "$dir" status --short) != "" ]]; then
  dirty=".dirty"
fi

# Get sorted annotated tag list from specified commit descendent commit tree

tag_multiline_list=$(git -C "$dir" tag --list --sort="version:refname" --merged="$commit" --format="%(objecttype) %(refname:short)" -- "$tag_prefix*")

new_line="
"
debug "tag_multiline_list: ${tag_multiline_list//$new_line/; }"

# Get annotated tag name with biggest version
# in specified commit descendent commit tree

filtered_lines=$(echo "$tag_multiline_list" | grep "^tag " || true)
tag_name=$(echo "$filtered_lines" | sed "s/^tag //" | tail -n 1)

dbg_print_var "tag_name"

# ==================================================

major="0"
minor="0"
patch_level=""
commit_hash=""

if [[ "$tag_name" != "" ]]; then
  # Calculate commit offset from specified tag
  # and get truncated commit hash

  # Example of describe_line:
  # epoch/v22.11-12-g9382ab

  describe_line=$(git -C "$dir" describe --abbrev=$commit_hash_length --long --match="$tag_name" -- "$commit")

  dbg_print_var "describe_line"

  # Parse describe_line into parts
  # Example of str:
  # 22.01-12-g9382ab

  str=${describe_line#"$tag_prefix"}
  str_regex="^([0-9]+)\\.0*([1-9][0-9]*|0)-([0-9]+)-g([0-9a-f]{$commit_hash_length})$"

  dbg_print_var "str"
  dbg_print_var "str_regex"

  if [[ $str =~ $str_regex ]]; then
    major="${BASH_REMATCH[1]}"
    minor="${BASH_REMATCH[2]}"
    patch_level="${BASH_REMATCH[3]}"
    commit_hash="${BASH_REMATCH[4]}"

    dbg_print_var "major"
    dbg_print_var "minor"
    dbg_print_var "patch_level"
    dbg_print_var "commit_hash"
  fi
fi

if [[ "$patch_level" == "" ]]; then
  patch_level=$(git -C "$dir" rev-list --count "$commit")
  dbg_print_var "patch_level"
fi

if [[ "$commit_hash" == "" ]]; then
  commit_hash=$(git -C "$dir" rev-parse --short=$commit_hash_length "$commit")
  dbg_print_var "commit_hash"
fi

# ==================================================

# Final software version formatting

echo "$major.$minor.$patch_level-$current_day_string.$commit_hash$dirty"

# ==================================================