Merge GitHub PR locally with signed merge commit

merge_pr.sh

#!/usr/bin/env sh

# You need the GitHub cli for this script (gh)
# Launch it from the branch you want to be merged in
# Example:
# $ git status
# On branch master
# ...
# $ merge_pr name_of_the_branch_to_merge

if [ -z "$1" ]; then
    echo "No argument supplied"
    [[ "$0" = "$BASH_SOURCE" ]] && exit 1 || return 1
fi

set -e

base_message=$(gh pr view $1 --json author,body,number,title \
    -q '. | "Merge #\(.number) \"\(.title)\" from \(.author.name)\n\n\(.body)"')

git merge --no-ff --signoff -m "$base_message" -e $1