hg-fast-export 20120618-1 / usr / bin / git-hg

#!/usr/bin/env bash

if which python2 >&/dev/null; then
    PYTHON=python2
    export PYTHON
fi

set -e

# Try to use GNU Coreutils readlink --canonicalize if available,
# falling back to less robust shell script only if not found.
if which greadlink >&/dev/null; then
    canon="greadlink --canonicalize"
elif readlink --canonicalize / >&/dev/null; then
    canon="readlink --canonicalize"
else
    canon=canonicalize
fi

function canonicalize {
    path="$1"
    
    while [ -L "$path" ]; do
	dir=$(dirname "$path")
	path=$(ls -l "$path" | sed -e 's/.* -> //')
	cd "$dir"
    done
    
    dir=$(dirname "$path")
    file=$(basename "$path")
    if [ ! -d "$dir" ]; then
	echo "canonize: $dir: No such directory" >&2
	exit 1
    fi
    cdir=$(cd "$dir" && pwd -P)
    printf "%s/%s\n" "$cdir" "$file"
}

function git-current-branch {
    git branch | egrep '^[*]' | sed 's/^\* \(.\)/\1/'
}

function check-hg-fast-export {
    # Search for hg-fast-export $PATH, use if available, if not fall back
    # to looking around for it in sibling directory of bin directory of
    # the current exeuctable, possibly tracing back along symbolic link.
    if type hg-fast-export > /dev/null 2>&1 ; then
	HG_FAST_EXPORT=hg-fast-export
    else
	GITHG_HOME=$($canon $(dirname $($canon $0))/..)
	HG_FAST_EXPORT=$GITHG_HOME/fast-export/hg-fast-export.sh
	if type $HG_FAST_EXPORT > /dev/null 2>&1 ; then
	    echo looking good > /dev/null
	else
	    echo "error: executable not found, $HG_FAST_EXPORT"
	    echo 'Possible fixes: run "git submodule update --init" in git-hg repo, or'
	    echo 'install hg-fast-export executable in directory on $PATH.'
	    exit 1
	fi
    fi
}

function git-hg-clone {
    check-hg-fast-export
    
    if [[ $1 == "--force" ]]; then
        FORCE="--force"
        shift
    fi
    HG_REMOTE=$1
    
    if [ -z "$2" ]; then
        CHECKOUT=$(basename $1)
    else
        CHECKOUT=$2
    fi
    if [ -a $CHECKOUT ]; then
	echo error: $CHECKOUT exists
	exit 1
    fi
    git init $CHECKOUT
    (
	cd $CHECKOUT
	hg clone -U $HG_REMOTE .git/hgcheckout
	git init --bare .git/hgremote
	(
	    cd .git/hgremote
	    $HG_FAST_EXPORT -r ../hgcheckout $FORCE
	)
	git remote add hg .git/hgremote
	git fetch hg
        if git branch -r | grep -q master; then
	    local branch="master"
        else
            local branch=$(cd .git/hgcheckout/ && hg tip | grep branch | awk '{print $2}')
        fi
        git config hg.tracking.master $branch
        git pull hg $branch
    )
}

function git-hg-fetch {
    check-hg-fast-export
    if [[ $1 == "--force" ]]; then
        FORCE="--force"
        shift
    fi
    hg -R .git/hgcheckout pull
    (
	cd .git/hgremote
	$HG_FAST_EXPORT $FORCE
    )
    git fetch hg
}

function git-hg-pull {
    while [ $# -gt 0 ]; do
        case "$1" in
        --rebase)
            REBASE="--rebase"
            shift
            ;;
        --force)
            FORCE="--force"
            shift
            ;;
        esac
    done

    git-hg-fetch $FORCE

    local current_branch=$(git-current-branch)
    local remote_branch

    if [ $current_branch == "master" ]; then
        remote_branch=$(git config hg.tracking.master || true)
        
        if [[ -z $remote_branch ]]; then
            if git branch -r | grep -q master; then
                remote_branch="master"
                git config hg.tracking.master $branch
            else
                echo "ERROR: Cannot determine remote branch. There is no remote branch called master, and hg.tracking.master not set. Merge the desired branch manually."
                exit 1
            fi
        fi
    else
        remote_branch=$(git config hg.tracking.${current_branch} || true)
        if [[ -z $remote_branch ]]; then
             echo "ERROR: Cannot determine the remote branch to pull from. Run git merge manually against the desired remote branch."
             echo "Alternatively, set hg.tracking.$current_branch to the name of the branch in hg the current branch should track"
             exit 1
        fi
    fi

    if [ "--rebase" = "$REBASE" ]; then
        git rebase hg/$remote_branch
    else
        git merge hg/$remote_branch
    fi
}

function git-hg-checkout {
    if [[ $1 == "--force" ]]; then
        FORCE="--force"
        shift
    fi
    git-hg-fetch $FORCE
    git checkout hg/$1 -b $1
}

function git-hg-push {
    HG_REPO=$1
    hg convert . .git/hgcheckout
    hg -R .git/hgcheckout push $HG_REPO
}

function usage {
    echo "To clone a mercurial repo run:"
    echo "  clone <path/to/mercurial/repo> [local_checkout_path]"
    echo ""
    echo " if that fails (due to unnamed heads) try:"
    echo "  git-hg clone --force <path/to/mercurial/repo> [local_checkout_path]"
    echo ""
    echo "To work with a cloned mercurial repo use: "
    echo "  fetch [ --force ]                   fetch latest branches from mercurial"
    echo "  pull [ --force ] [ --rebase ]       fetch and merge (or rebase) into the"
    echo "                                      current branch"
    echo "  push [destination]                  push latest changes to mercurial"
    echo "  checkout [ --force ] branch_name    checkout a mercurial branch"
}

case "$1" in
    clone)
	git-hg-clone $2 $3 $4
	;;
    fetch)
	git-hg-fetch $2
	;;
    pull)
	git-hg-pull $2 $3
	;;
    checkout)
	git-hg-checkout $2 $3
	;;
    push)
        git-hg-push $2
        ;;
    *)
	usage
	exit 1
	;;
esac