Fetch, prune, & delete merged local git branches

git-local-cleanup.sh

#!/bin/bash
set -x  # turn on debugging
set -e  # exit on fail

########################################################################
#
# Fetch, prune, & delete merged local git branches
#
########################################################################

date
pwd

root=$(git rev-parse --show-toplevel)
here=$(git rev-parse --abbrev-ref HEAD)
echo "current branch: $here"
trap "cd $root && git checkout $here && git pull" EXIT  # always return to original branch

DEFAULT_BRANCH=$(git symbolic-ref refs/remotes/origin/HEAD | sed 's@^refs/remotes/origin/@@')
echo "default branch: $DEFAULT_BRANCH"
git checkout $DEFAULT_BRANCH

echo "---"

echo "[fetch + prune remote references]"
git fetch -p

echo "---"

echo "[all branches]"
git branch -a

echo "---"

echo "[local branches]"
git branch -vv

echo "---"

echo "[delete merged local branches]"

# git for-each-ref refs/heads/ "--format=%(refname:short)" | while read branch; do
#     echo "$branch:"
#     mergeBase=$(git merge-base $DEFAULT_BRANCH $branch)
#     echo "   best common ancestor with $DEFAULT_BRANCH: $mergeBase"
#     if [[ $(git cherry $DEFAULT_BRANCH $(git commit-tree $(git rev-parse "$branch^{tree}") -p $mergeBase -m _)) == "-"* ]]; then
#         echo "   remote has been merged! deleting $branch"
#         git branch -D $branch
#     else
#         echo "   local branch has not been merged into $DEFAULT_BRANCH"
#     fi
# done

# https://stackoverflow.com/a/33548037/13156561
for branch in $(git for-each-ref --format '%(refname) %(upstream:track)' refs/heads | awk '$2 == "[gone]" {sub("refs/heads/", "", $1); print $1}'); do
    # echo $branch
    git branch -D $branch
done

echo "---"

echo "[local branches]"
git checkout $here || true  # branch may have been deleted
git branch -a

git pull