git-branch-content-merged

#!/bin/bash

set -euo pipefail

# Define color codes
RED="\033[0;31m"
GREEN="\033[0;32m"
YELLOW="\033[0;33m"
RESET="\033[0m"

current_branch=$(git symbolic-ref --short HEAD 2>/dev/null || echo '')
default_branch=$(git symbolic-ref refs/remotes/origin/HEAD | sed 's@^refs/remotes/@@')

# Check the last modification time of FETCH_HEAD
current_time=$(date +%s)  # current time in seconds since 1970-01-01 00:00:00 UTC
git_fetch_head_path=$(git rev-parse --show-toplevel)/.git/FETCH_HEAD
last_fetch_time=$(stat -c %Y "$git_fetch_head_path")  # last modification time of FETCH_HEAD in seconds since 1970-01-01 00:00:00 UTC

# If more than 1 hour (3600 seconds) has passed since the last fetch, then fetch again
if (( current_time - last_fetch_time > 3600 )); then
    git fetch origin
    echo ""
fi

max_branch_name_length=$(git for-each-ref refs/heads/ "--format=%(refname:short)" | awk '{ if (length > max) max = length } END { print max }')

# based on https://stackoverflow.com/a/56026209

git for-each-ref refs/heads/ "--format=%(refname:short)" | while read branch; do
    padded_branch=$(printf "%-${max_branch_name_length}s" "$branch")

    prefix="  "
    [ "$branch" == "$current_branch" ] && prefix="* "

    if git merge-base --is-ancestor $branch $default_branch; then
        echo -e "${prefix}[${GREEN}V${RESET}] ${YELLOW}${padded_branch}${RESET}  is fully contained within $default_branch and can be safely deleted"
    else
        mergeBase=$(git merge-base $default_branch $branch)
        commitTree=$(git rev-parse "$branch^{tree}")
        cherryCommit=$(git commit-tree $commitTree -p $mergeBase -m _)

        ahead_count=$(git rev-list --count $default_branch..$branch)
        behind_count=$(git rev-list --count $branch..$default_branch)

        # Construct the ahead/behind message
        ahead_msg=""
        [ $ahead_count -gt 0 ] && ahead_msg="ahead $ahead_count"
        
        behind_msg=""
        [ $behind_count -gt 0 ] && behind_msg="behind $behind_count"

        join_char=", "
        [[ -z "$ahead_msg" || -z "$behind_msg" ]] && join_char=""

        if [[ $(git cherry $default_branch $cherryCommit) == "-"* ]]; then
            echo -e "${prefix}[${GREEN}V${RESET}] ${YELLOW}${padded_branch}${RESET}  is squash/rebase merged into $default_branch and can be safely deleted [$ahead_msg$join_char$behind_msg]"
        else
            echo -e "${prefix}[${RED}x${RESET}] ${YELLOW}${padded_branch}${RESET}  is ${RED}NOT${RESET} merged into $default_branch [$ahead_msg$join_char$behind_msg]"
        fi
    fi
done