pdx86-merge-immutable

#!/bin/sh

# Use this script to conveniently merge a remote immutable branch without adding
# a remote. It will fetch the remote branch to an anonymous local branch
# and merge it into the current branch. It will open EDITOR to allow for changes
# to the merge commit message (necessary if you do not provide JUSTIFICATION).
# On a successful merge, it will display the merge commit message.

usage() {
	echo "Usage: $(basename $0) GIT_URI BRANCH [JUSTIFICATION]"
	echo ""
	echo "  -h             display this help and exit"
	echo "  GIT_URI        git URI to fetch BRANCH from"
	echo "  BRANCH         branch to fetch and merge from GIT_URI"
	echo "  JUSTIFICATION  short phrase justifying the merge, e.g. 'avoid linux-next conflicts'"
}

if [ "$1" = "-h" ]; then
	usage
	exit 0
elif [ $# -lt 2 ] || [ $# -gt 3 ]; then
	usage
	exit 1
fi

URL=$1
BRANCH=$2
JUSTIFICATION="SHORT JUSTIFICATION"
if [ -n "$3" ]; then
	JUSTIFICATION="$3"
fi

# Prepare the git merge commit message
# If you did not provide JUSTIFICATION, you will need to provide it in EDITOR
SOB="Signed-off-by: $(git config user.name) <$(git config user.email)>"
MSG="$(printf "Merge branch '$2'\n\nMerge branch '$2' of\n$1\nto $JUSTIFICATION.\n\n$SOB")"

# Perform the commands in sequence, catching a failure at any point
git fetch -q $1 $2 && git merge -q -e -m "$MSG" FETCH_HEAD

if [ $? -ne 0 ]; then
	echo "Error: Failed to merge $1 $2"
	exit 1
fi

echo -e "\nMerged $1 $2:\n"
git log -1