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#!/bin/sh
#
# Usage: git semver-tags [-p|--pre]
#
# Lists semver tags in the repository in order from newest to oldest.
#
# Useful for e.g. programmatically finding the latest release tag:
# `git semver-tags | head -n 1`.
#
# Tag names must be valid according to the SemVer 1.0.0 specification
# (http://semver.org/spec/v1.0.0.html), with the following additional
# considerations:
#
# 1. The tag name may optionally start with a "v".
# 2. The minor and patch versions may be omitted in the tag name, in
# which case they will be treated as equivalent to "0".
#
# By default, tags with prerelease segments are not included in the
# list. To see all tags, including those with prerelease segments,
# pass the `-p` or `--pre` option.
#
# Copyright (c) 2012 Sam Stephenson <sstephenson@gmail.com>
# Released into the public domain 2012-12-21
set -e
preprocess_tags() {
sed -e "
# If the line isn't a semver tag name, delete it and
# continue processing.
/^v\{0,1\}[0-9]\{1,\}\(\.[0-9]\{1,\}\)\{0,1\}\(\.[0-9]\{1,\}\)\{0,1\}\(-[A-Za-z0-9-]\{1,\}\)\{0,1\}$/ !{
d
b
}
# Store the semver tag in the hold buffer.
h
# Strip off the leading 'v', if present, and replace all
# dots with spaces.
s/^v//
s/\./ /g
# If there is no prerelease segment, add one called '~'
# so it occurs last when sorted.
/-./ !{
s/-\{0,1\}$/-~/
}
# Two spaces in the string means that major, minor, and
# patch versions are specified. Skip to :end.
/ .* / {
b end
}
# One space in the string means there's no patch version.
# Set it to '0' and skip to :end.
/ / {
s/-.*$/ 0&/
b end
}
# No spaces in the string means there's only a major
# version. Set minor and patch to '0'.
s/-.*$/ 0 0&/
:end
# Replace the prerelease segment junction with a space.
s/-/ /
# Restore the semver tag name from the hold buffer.
G
# Remove the newline added by the hold buffer restoration
# so the semver tag name appears on the same line.
s/\n/ /
"
}
format_preprocessed_tags_for_sorting() {
awk '
# Record each line, keeping track of the maximum widths of
# the first three columns.
{
lines[NR] = $0
for (i = 1; i <= 3; i++) {
max[i] < length($i) && max[i] = length($i)
}
}
# Loop over each line and print it in a format suitable for
# ASCII sorting. First, print each of the first three columns
# zero-padded to its maximum width, followed immediately by
# the fourth column, then a space, and finally the fifth.
END {
for (i = 1; i <= NR; i++) {
split(lines[i], parts, FS)
printf("%0" max[1] "d%0" max[2] "d%0" max[3] "d%s %s\n",
parts[1], parts[2], parts[3], parts[4], parts[5])
}
}
'
}
filter_prerelease_tags() {
if [ -n "$prerelease" ]; then
cat
else
grep "~"
fi
}
usage() {
echo "usage: git semver-tags [-p|--pre]" >&2
exit 1
}
unset prerelease
for arg; do
case "$arg" in
-p | --pre )
prerelease="1"
;;
* )
usage
;;
esac
done
git tag -l |
preprocess_tags |
filter_prerelease_tags |
format_preprocessed_tags_for_sorting |
sort -r |
awk '{print $2}'
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