gh-pull.sh

#!/bin/bash

set -e

function clone {
    if [ ! -z "$3" ]; then
        cmd="git clone --depth=50 --branch=$3 git@github.com:$1.git $2"
    else
        cmd="git clone --depth=50 git@github.com:$1.git $2"
    fi;

    echo "-> $cmd"
    $cmd
}

function fetch {
    cmd="git fetch origin +$1:"
    echo "-> $cmd"
    $cmd
}

function checkout {
    cmd="git checkout -qf $1"
    echo "-> $cmd"
    $cmd
}

command -v git >/dev/null 2>&1 || { echo >&2 "I require git but it's not installed ;("; exit 1; }

usage="Usage `basename $0` [--help] [-o -h -f] repository target -- Clone and checkout repository

where:
    -o         output directory (default: "repository")
    -h         hash of commit
    -f         force
    --help     show this help text
    repository github repository
    target	   target branch or pull request
"

repo=""
target=$2
output=""
hash="HEAD"
force=false

if [ $# == 0 ] || [ $1 == "--help" ]; then
    echo "$usage"
    exit 0
fi

while getopts :r:t:o:f option
do
    case "${option}"
    in
        h) hash=${OPTARG};;
        o) output=${OPTARG};;
        f) force=true;;
        *) repo=${OPTARG};;
    esac
done

shift $(($OPTIND - 1))
repo=$1
target=$2

if [ -z "$output" ]; then
    output="$repo"
fi

if [ $force == true ] && [ -d $output ]; then
    find -P $output -mindepth 1 -maxdepth 1 -exec rm -rf {} \;
fi

if [[ $target == "pull/"* ]]; then
    hash="FETCH_HEAD"
fi

if [[ $target == "pull/"* ]]; then
    clone $repo $output
    (cd $output && fetch "refs/$target/merge")
else
    clone $repo $output $target
fi
(cd $output && checkout $hash && echo "$target" > fetch.target)