git-rbranch

#!/bin/bash
#

function usage() {
    echo "Usage: git rbranch [-c] [-e] [-p] [<remote>] <branch> [<from>]"
    echo
    echo "If you want to create a local branch that will later track a remote"
    echo "branch, but it does not yet exist, you can use this command instead"
    echo "of setting up configuration manually or deleting and re-creating"
    echo "your local branch later, after it's been pushed."
    echo
    echo "Args:"
    echo "    -c         - Only create the branch, don't check it out"
    echo "    -e         - Don't create an empty commit at the start of the branch (default"
    echo "                 is to create such a commit)"
    echo "    -p         - Only create the branch, don't check it out"
    echo "    <remote>   - A remote repository, defaults to 'origin'"
    echo "    <branch>   - The name of a remote branch"
    echo "    <from>     - Starting point for the new branch"
}

# Default values for options
checkout=yes
empty=yes
push=no

GETOPT=$(getopt -u -o hcep -- "$@")
if [[ $? != 0 ]]; then
    usage
    exit 1
fi
set -- $GETOPT

while [[ 0 != $# ]]; do
    case "$1" in
        -c)
            checkout=no
            ;;
        -e)
            empty=no
            ;;
        -p)
            push=yes
            ;;
        -h)
            usage
            exit 0
            ;;
        --)
            shift
            break
            ;;
        *)
            echo "Unrecognized option ($1)??" >&2
            usage
            exit 1
            ;;
    esac
    shift
done


if [[ $# -lt 1 || 3 -lt $# ]]; then
    usage
    exit 1
fi

remote=$1; shift;

# If remote is not recognized, assume origin
if [[ -z $(git config --get "remote.$remote.url") ]]; then
    branch=$remote
    remote="origin"
else
    branch=$1; shift;
fi

# If a remote is actually given as part of the branch, split them and use it
if [[ $(echo $branch | awk '$1 ~ /\// { print }') ]]; then
    remote="${branch%%/*}"
    branch="${branch##*/}"
fi

if [[ -z $(git config --get "remote.$remote.url") ]]; then
    echo "Unrecognized remote repository, $remote." >&2
    exit 1
fi

from=$1

# Now that we have our arguments, first check to see if the branch already exists
if [[ -n $(git for-each-ref "refs/heads/$branch") ]]; then
    echo "$branch already exists, not creating."

    if [[ -z $(git for-each-ref "refs/remotes/$remote/$branch") ]]; then
        echo "Warning: The tracking branch $remote/$branch does not (yet) exists" >&2
    fi
    # It does.  Is it already tracking?
    current_remote=$(git config --get "branch.$branch.remote")
    current_merge=$(git config --get "branch.$branch.merge")

    if [[ -z $current_merge ]]; then
        # Not tracking, set it up
        git config "branch.$branch.remote" "$remote"
        git config "branch.$branch.merge" "refs/heads/$branch"
        echo "$branch set up to track $remote/$branch"
    else
        if [ "$remote" = "$current_remote" -a "$current_merge" = "refs/heads/$branch" ]; then
            echo "$branch is already tracking $remote/$branch"
        else
            echo "$branch is tracking $current_remote/$current_remote_head instead!"
            exit 1
        fi
    fi
else
    # It doesn't, so let's create it
    echo "] git branch $branch" $from
    # Don't quote $from here because passing an empty string is an error
    git branch --no-track "$branch" $from || exit $?

    git config "branch.$branch.remote" "$remote"
    git config "branch.$branch.merge" "refs/heads/$branch"
    echo -n "Created branch $branch tracking $remote/$branch from "
    if [[ -n $from ]]; then
        where=$from
    else
        head=$(git symbolic-ref HEAD 2>/dev/null)
        head=${head##refs/heads/}
        if [[ -n $head ]]; then
            where=$head
        else
            where=HEAD
        fi
    fi
    echo $where

    commit_message="Created branch $branch from $where"
    created_branch=1
fi

if [[ yes = $checkout ]]; then
    echo "] git checkout $branch"
    git checkout "$branch"
fi

if [[ -n $created_branch && yes = $empty ]]; then
    git commit --allow-empty -m "$commit_message"
fi

if [[ -n $created_branch && yes = $push ]]; then
    git pushme
fi