Find squash-commited branches that can be deleted

README.md

Git Branch Audit

1. It retrieves the name of the default branch from the remote repository using the git ls-remote command.
2. It checks out the default branch locally.
3. It lists all local branches using the git for-each-ref command.
4. For each local branch, it finds the merge base between the default branch and the current branch using the git merge-base command.
5. It creates a temporary commit tree for the current branch using the git commit-tree command.
6. It checks if the temporary commit is a descendant of the default branch using the git cherry command.
7. If the temporary commit is not a descendant (i.e., the branch has been merged into the default branch), it prints a message indicating that the branch can be deleted.

Essentially it fakes a squash merge for each branch and then checks of the default branch is a decendent from this. It will also print the branches that were merged in the "normal" way, i.e. git merge.

git-audit.sh

#!/usr/bin/env bash
set -e

# Function to display the help text
display_help() {
  echo "Usage: git-audit [OPTIONS]"
  echo "Check for merged branches in a Git repository and print messages indicating whether each branch is merged and can be deleted."
  echo ""
  echo "Options:"
  echo "  -q      Quiet mode. Only print the branch names without additional messages."
  echo "  -h      Display this help message."
  echo ""
  echo "Example:"
  echo "  git-audit -q | xargs -n 1 git branch -D"
}

quiet=false
while getopts "qh" opt; do
  case $opt in
    q)
      # Set the quiet flag to true if the -q option is provided
      quiet=true
      ;;
    h)
      # Display the help text and exit if -h or --help option is provided
      display_help
      exit 0
      ;;
    \?)
      # Print an error message and exit if an invalid option is provided
      echo "Invalid option: -$OPTARG" >&2
      exit 1
      ;;
  esac
done

# Shift the processed options, so the remaining arguments are accessible
shift $((OPTIND - 1))

# Get the default branch of the repository
default_branch=$(git ls-remote --symref origin HEAD | sed -nE 's|^ref: refs/heads/(\S+)\s+HEAD|\1|p')

# Function to print the branch message
print_branch_message() {
  local branch=$1

  # Check if the script is running in quiet mode
  if [ "$quiet" = true ]; then
    echo "$branch"
  else
    echo "$branch is merged into '$default_branch' and can be deleted"
  fi
}

# Switch to the default branch and iterate over all local branches
git checkout -q "$default_branch" && git for-each-ref refs/heads/ "--format=%(refname:short)" | while read branch; do
  # Find the merge base between the default branch and the current branch
  mergeBase=$(git merge-base $default_branch $branch)

  # Check if the branch is merged by comparing the result of git cherry with a hyphen
  if [[ $(git cherry $default_branch $(git commit-tree $(git rev-parse "$branch^{tree}") -p $mergeBase -m _)) == "-"* ]]; then
    print_branch_message "$branch"
  fi
done

# Get a list of merged branches and filter out the default branch
git branch --merged | grep -v "$default_branch" | while read merged; do
  print_branch_message "$branch"
done