bump_release_version_and_tag

#!/bin/sh
#
# Simple script to update the release version and tag according to that value.
# - release version now stored in RELEASE_VERSION e.g. 1.4.571
# - the tag usually is of the form v1.4.571.
#
# If there's a difference between current code and there are no pending changes
# then:
# - the current version will be increased by one
# - the RELEASE_VERSION updated accordingly
# - a new tag will be created
# - the tag will be pushed to origin (may need fixing)

diff=$(git diff)
rc=$?
if [ $rc != 0 ]; then
	echo "git diff failed. Doing nothing"
	exit 0
fi
if [ -n "$diff" ]; then
	echo "Some pending changes need committing. Doing nothing"
	exit 0
fi
old_version=$(cat RELEASE_VERSION)
old_tag=v$old_version
diff=$(git diff $old_tag)
rc=$?
if [ $rc = 128 ]; then
	echo "git diff $old_tag failed. Revision unknown. Doing nothing"
	exit 0
fi
if [ $rc != 0 ]; then
	echo "git diff $old_tag failed. Doing nothing"
	exit 0
fi
if [ -z "$diff" ]; then
	echo "No differences against $old_version. Doing nothing"
	exit 0
fi

echo "We need to bump the version"
echo "OLD: version: $old_version, tag: $old_tag"
# now generate a new version.
last_digit=$(echo "$old_version" | sed -e 's/.*\.//')
new_digit=$(($last_digit + 1))
new_version=$(echo "$old_version" | sed -e "s/\.[0-9]*$/.$new_digit/")
new_tag=v$new_version
echo "NEW: version: $new_version, tag: $new_tag"
echo "Modifying RELEASE_VERSION..."
echo "$new_version" > RELEASE_VERSION
echo "Committing change to RELEASE_VERSION..."
git add RELEASE_VERSION
git commit -m"bump RELEASE_VERSION from $old_version to $new_version"
echo "Adding new tag: $new_tag"
git tag $new_tag
echo "Pushing changes and new tag..."
git push
git push origin $new_tag