dev

#!/bin/bash

export LANG="C"
export LC_ALL="C"

GEM_RE='([^0-9].*)-([0-9].*)'

readonly currdir="$PWD"
export PATH="$PATH:/sbin:/usr/sbin:/usr/local/sbin"
declare -A DEV_BRANCHES DEV_REMOTE_SOURCES DEV_REMOTE_BRANCHES DEV_ORIGIN_TYPES
declare -a DEV_REMOTES DEV_ALL_REMOTES

# The generation of the dev tool this is.
readonly DEV_VERSION=1

# The key -> value mapping in DEV_BRANCHES defines child -> parent relations
# between branches.  A branch is considered a root branch if it has itself
# as a parent.
DEV_BRANCHES["master"]="master"
DEV_BRANCHES["openstack-os-build"]="master"
DEV_BRANCHES["hadoop-os-build"]="master"
DEV_BRANCHES["cloudera-os-build"]="master"

# DEV_REMOTE_SOURCES defines the source parts of the URLs that the
# various remotes map to.  The "personal" remote is not listed in this
# hash, and most of the script assumes that origin always points at
# github and that the personal remote should be used as a backup target
# for all branches that were pulled from origin.
DEV_REMOTE_SOURCES["origin"]="https://github.com/dellcloudedge"

# DEV_REMOTE_BRANCHES defines what branches in the main Crowbar repository
# should be pulled and synced with what remotes.
# Barclamps do care about remote branches.
DEV_REMOTE_BRANCHES["origin"]="master openstack-os-build hadoop-os-build cloudera-os-build"

# DEV_REMOTES holds the remotes we will work on in the order they should be
# worked on when ordering matters.
DEV_REMOTES=("origin")

# Source our config file if we have one
[[ -f $HOME/.build-crowbar.conf ]] && \
    . "$HOME/.build-crowbar.conf"

# Look for a local one.
[[ -f build-crowbar.conf ]] && \
    . "build-crowbar.conf"

# Set up our proxies if we were asked to.
if [[ $USE_PROXY = "1" && $PROXY_HOST ]]; then
    proxy_str="http://"
    if [[ $PROXY_PASSWORD && $PROXY_USER ]]; then
        proxy_str+="$PROXY_USER:$PROXY_PASSWORD@"
    elif [[ $PROXY_USER ]]; then
        proxy_str+="$PROXY_USER@"
    fi
    proxy_str+="$PROXY_HOST"
    [[ $PROXY_PORT ]] && proxy_str+=":$PROXY_PORT"
    [[ $no_proxy ]] || \
        no_proxy="localhost,localhost.localdomain,127.0.0.0/8,$PROXY_HOST"
    [[ $http_proxy ]] || http_proxy="$proxy_str/"
    [[ $https_proxy ]] || https_proxy="$http_proxy"
    export no_proxy http_proxy https_proxy
else
    unset no_proxy http_proxy https_proxy
fi

DEV_ALL_REMOTES=("${DEV_REMOTES[@]}")
[[ $DEV_AVAILABLE_REMOTES ]] && DEV_REMOTES=($DEV_AVAILABLE_REMOTES)

# Location of the Crowbar checkout we are building from.
[[ $CROWBAR_DIR ]] || CROWBAR_DIR="${0%/*}"
[[ $CROWBAR_DIR = /* ]] || CROWBAR_DIR="$currdir/$CROWBAR_DIR"
[[ -f $CROWBAR_DIR/build_crowbar.sh && -d $CROWBAR_DIR/.git ]] || \
    die "$CROWBAR_DIR is not a git checkout of Crowbar!"
export CROWBAR_DIR

. "$CROWBAR_DIR/build_lib.sh" || exit 1
trap - 0 INT QUIT TERM

if [[ $DEV_GITHUB_PASSWD ]]; then
    debug "Migrating Github password information to $HOME/.netrc"
    for mach in github.com api.github.com; do
        grep -q "^$mach" "$HOME/.netrc" &>/dev/null && continue
        printf "\nmachine %s login %s password %s\n" \
            "$mach" "$DEV_GITHUB_ID" "$DEV_GITHUB_PASSWD" >> "$HOME/.netrc"
    done
    chmod 600 "$HOME/.netrc"
    sed -ie 's/DEV_GITHUB_PASSWD=.*//' "$HOME/.build-crowbar.conf"
    debug "Please remove your embedded login information from the remote URLS."
fi

which gem &>/dev/null || \
    die "Rubygems not installed, and some of our helpers need a JSON gem."

gem list -i json &>/dev/null || \
    die "JSON gem not installed.  Please install it with gem install json."

get_repo_cfg() { in_repo git config --get "$1"; }
get_barclamp_cfg() { in_barclamp "$1" git config --get "$2"; }

dev_is_setup() {
    [[ $DEV_GITHUB_ID || $1 = setup ]] || \
        die "dev has not been configured. Please run $CROWBAR_DIR/dev setup first."

    thisrev=$(get_repo_cfg crowbar.dev.version) && \
        (( thisrev  == DEV_VERSION )) || [[ $1 = setup ]] || {
        VERBOSE=true
        debug "Crowbar repository out of sync with dev tool revision."
        debug "Please run $0 setup to update it."
        exit 1
    }
}

unset thisrev

set -o pipefail

# Given a branch, echo all the child branches for this
# branch in the same release.
child_branches() {
    local prefix="${1%/*}/" parent=${1##*/} br
    [[ ${prefix%/} = $1 ]] && prefix=''
    for br in "${!DEV_BRANCHES[@]}"; do
        [[ ${DEV_BRANCHES[$br]} && \
            ${DEV_BRANCHES[$br]} != $br && \
            ${DEV_BRANCHES[$br]} = $parent ]] || continue
        in_repo branch_exists "$prefix$br" || continue
        echo "$prefix$br"
    done
    return 0
}

# Given a branch, echo its parent in the current release.
parent_branch() {
    local prefix="${1%/*}/" parent=${1##*/} br
    [[ ${prefix%/} = $1 ]] && prefix=''
    local p="${DEV_BRANCHES[${1##*/}]}"
    if [[ $p && $p != ${1##*/} ]]; then
        echo "${prefix}${p}"
        return 0
    fi
    return 1
}

# Echo all of the root branches in the current release.
root_branches() {
    local b release releases=() prefix
    case $1 in
        '') releases=("$(current_release)");;
        '--all') releases=($(show_releases));;
        *) is_in "$1" "$(show_releases)" || \
            die "root_branches: $1 is not a release!"
            releases=("$1");;
    esac
    for release in "${releases[@]}"; do
        prefix="$(branch_prefix "$release")"
        for b in "${!DEV_BRANCHES[@]}"; do
            [[ $b = ${DEV_BRANCHES[$b]} ]] || continue
            in_repo branch_exists "${prefix}$b" || continue
            echo "${prefix}$b"
        done
    done
    return 0
}

ordered_branches() {
    # $@ = branches to print all of the children of.
    [[ $@ ]] && local branches=("$@") || local branches=("$(root_branches)")
    local b children=()
    printf "%s\n" "${branches[@]}"
    for b in "${branches[@]}"; do
        children=($(child_branches "$b"))
        [[ $children ]] && ordered_branches "${children[@]}"
    done
}

all_ordered_branches() { ordered_branches $(root_branches --all); }

branches_for_release() { ordered_branches $(root_branches "$1"); }

# Given a branch, print the first remote that branch is "owned" by
remote_for_branch() {
    local remote
    for remote in "${DEV_ALL_REMOTES[@]}"; do
        is_in "${1##*/}" "${DEV_REMOTE_BRANCHES[$remote]}" || continue
        echo "$remote"
        return 0
    done
    return 1
}

# Given a remote and a list of branches,
# return just the branches that are in that remote.
filter_branches_for_remote() {
    local remote="$1" b
    shift
    for b in "$@"; do
        is_in "${b##*/}" "${DEV_REMOTE_BRANCHES[$remote]}" || continue
        echo "$b"
    done
}

# Test to see if a specific repository is clean.
# Ignores submodules and unchecked-in directories that are git repositories.
git_is_clean() {
    local line hpath ret=0 opt
    local stat_cmd="git status --porcelain --ignore-submodules" quiet=''
    local paths=()
    while [[ $1 ]]; do
        opt="$1"; shift
        case $opt in
            --barclamps) stat_cmd="git status --porcelain";;
            -q|--quiet) quiet=true;;
            --paths)
                while [[ $1 && $1 != '-'* ]]; do
                    paths+=("$1")
                    shift
                done;;
            *) die "Unknown option $opt passed to git_is_clean.";;
        esac
    done
    [[ $paths ]] && stat_cmd+=" -- ${paths[*]}"
    while read line; do
        case $line in
            # Untracked file.  Ignore it if it is also a git repo,
            # complain otherwise.
            '??'*) hpath=${line%% ->*}
                   hpath=${hpath#* }
                   [[ -d $PWD/$hpath.git || -f $PWD/$hpath.git ]] && continue
                   ret=1; break;;
            '') continue;;
            *) ret=1; break;;
        esac
    done < <($stat_cmd)
    [[ $ret = 0 ]] && return
    [[ $quiet ]] || {
        echo "$PWD:"
        git status -- "${paths[@]}"
    }
    [[ $IGNORE_CLEAN ]] && return 0
    return 1
}

git_push() {
    [[ $DEBUG = true ]] && return
    git push "$@"
}

# Get the current release we are working on, which is a function of
# the currently checked-out branch.
current_release() {
    local ans="$(in_repo git symbolic-ref HEAD)" || \
        die "current_release: Cannot get current branch information!"
    ans=${ans#refs/heads/}
    case $ans in
        personal/*) continue;;
        stable/*) echo "stable";;
        release/*)
            ans="${ans#release/}"
            echo "${ans%%/*}";;
        feature/*) echo "${ans%/*}";;
        *) echo "development";;
    esac
}

# Test to see if a barclamp is clean.
barclamp_is_clean() {
    local bc="$1"; shift
    in_barclamp "$bc" git_is_clean "$@"; }

# Test to see if all our barclamps are clean.
barclamps_are_clean() {
    local bc res=0
    for bc in "$CROWBAR_DIR/barclamps/"*; do
        is_barclamp "${bc##*/}" || continue
        in_barclamp "${bc##*/}" git_is_clean "$@" || res=1
    done
    return $res
}

# Test to see if all the Crowbar repositories are clean.
crowbar_is_clean() {
    local res=0
    barclamps_are_clean "$@" && in_repo git_is_clean "$@" && return 0
    echo "Your crowbar repositories are not clean."
    echo "Please review the git status output above, and add and commit/stash as needed."
    return 1
}

# Get the list of barclamps that originate from this branch.
# $1 must be a branch name, and it must be some sort of release branch.
barclamps_from_branch() {
    # $1 = branch in Crowbar.
    is_in "${1##*/}" "${!DEV_BRANCHES[*]}" || \
        die "Will not be able to determine parent of $1."
    # If we don't have a parent branch, we are one of the roots.
    local parent=$(parent_branch "$1")
    if [[ ! $parent ]]; then
        barclamps_in_branch "$1"
        return 0
    fi
    sort <(barclamps_in_branch "$1") <(barclamps_in_branch "$parent") |uniq -u
}

# Perform an initial clone of a barclamp.  Takes care to ensure that
# the origin remote is set appropriatly.
clone_barclamp() {
    # $1 = name of the barclamp
    # $2 = name of remote to clone it from.
    local repo remote branch
    for remote in "${DEV_REMOTES[@]}"; do
        for branch in $(filter_branches_for_remote "$remote" \
            $(ordered_branches)); do
            is_in "$1" \
                "$(barclamps_in_branch $branch)" || \
            continue
            in_repo git submodule init "barclamps/$1"
            repo="$(get_repo_cfg "submodule.barclamps/$1.url")"
            repo="${repo##*/}"
            repo="${repo##*:}"
            repo="${repo%.git}"
            get_repo_cfg "submodule.barclamps/$1.url" \
                "${DEV_REMOTE_SOURCES[$remote]}/$repo"
            in_repo git submodule update "barclamps/$1" || \
                die "Could not perform initial clone of barclamp $1"
            (   cd "barclamps/$1"
                while read ref br; do
                    [[ br = refs/remotes/origin/* ]] || continue
                    br=${br#refs/remotes/}
                    branch_exists "${br#origin/}" && continue
                    git branch --track "${br#origin/}" "$br"
                done < <(git show-ref master)
            )
            return
        done
    done
    die "Asked to clone $1, but could not!"
}

quiet_checkout() {
    local res=''
    if ! res=$(git checkout -q "$@" 2>&1); then
        echo "$res" >&2
        return 1
    fi
}

keys() {
    local matcher="$1"
    shift
    while [[ $1 ]]; do
        [[ $1 =~ $matcher ]] && echo "$1"
        shift
    done
}

show_github_repos() {
    local -A res
    local r
    . <(curl_and_res -f "https://api.github.com/user/repos" | \
        parse_yml_or_json - res 2>/dev/null)
    for r in $(keys '^[0-9]+\.name$' "${!res[@]}"); do
        printf "%s\n" "${res[$r]}"
    done
}

__switch_barclamp_to() {
    local parent prefix parent_prefix ref
    parent="$(find_best_parent "$1")"
    prefix="$(branch_prefix "$1")"
    parent_prefix=$(branch_prefix "$parent")
    for ref in origin personal; do
        if git rev-parse --verify -q "$ref/${prefix}master" &>/dev/null; then
            git branch -f "${prefix}master" "$ref/${prefix}master"
            return 0
        fi
    done
    if ! branch_exists "${parent_prefix}master"; then
        __switch_barclamp_to "$parent" || exit 1
    fi
    git branch -f --no-track \
        "$(branch_prefix "$1")master" "${parent_prefix}master"
}

switch_barclamp_to() {
    # $1 = barclamp
    # $2 = release to switch to.
    local prefix
    prefix="$(branch_prefix "$2")"
    if ! in_barclamp "$1" branch_exists "${prefix}master"; then
        in_barclamp "$1" __switch_barclamp_to "$2" || exit 1
    fi
    in_barclamp "$1" quiet_checkout "${prefix}master";
}

# Set up barclamps for the appropriate branch.  Barclamps that are not members
# of the current branch will be checked out to an empty branch, which will be
# created if it does not exist.
switch_barclamps_to() {
    # $1 = Either a branch or "submodule-ref"
    local -A barclamps
    local m t ref p bc head
    # Read barclamps that should be there.
    while read m t ref p; do
        [[ $m = 160000 && $t = commit ]] || continue
        if [[ $1 = submodule-ref ]]; then
            barclamps[${p#/}]=$ref
        else
            barclamps[${p#/}]="refs/heads/$1"
        fi
    done < <(in_repo git ls-tree HEAD barclamps/)
    # Update barclamps that are there.
    for bc in "$CROWBAR_DIR/barclamps/"*; do
        [[ -d $bc/.git || -f $bc/.git ]] || \
            clone_barclamp "${bc##*/}"
        bc="${bc#$CROWBAR_DIR/}"
        if [[ ${barclamps[$bc]} && ${barclamps[$bc]} = refs/heads/* ]]; then
            head=$(in_barclamp "${bc##*/}" git symbolic-ref HEAD)
            [[ $head = ${barclamps[$bc]} ]] && {
                unset barclamps[$bc]
                continue
            }
            barclamps[$bc]="${barclamps[$bc]#refs/heads/}"
        elif [[ ${barclamps[$bc]} ]]; then
            ref=$(in_barclamp "${bc##*/}" git rev-parse --verify -q HEAD)
            [[ $ref = $(in_barclamp "${bc##*/}" \
                git rev-parse --verify -q "${barclamps[$bc]}") ]] && {
                unset barclamps[$bc]
                continue
            }
        else
            [[ $(in_barclamp "${bc##*/}" git symbolic-ref HEAD) = \
                refs/heads/empty-branch ]] && {
                unset barclamps[$bc]
                continue
            }
            barclamps[$bc]="the empty branch"
        fi
        debug "Barclamp ${bc##*/}: Checking out ${barclamps[$bc]}"
        case ${barclamps[$bc]} in
            'the empty branch') in_barclamp "${bc##*/}" to_empty_branch;;
            '') continue;;
            *) switch_barclamp_to "${bc##*/}" "$(release_for_branch "$1")";;
        esac || die "barclamp ${bc##*/}: Could not check out ${barclamps[$bc]}"
        unset barclamps[$bc]
    done
    # Create barclamps that are not there.
    for bc in "${!barclamps[@]}"; do
        [[ ${barclamps[$bc]} ]] || continue
        clone_barclamp "${bc##*/}"
        in_barclamp "${bc##*/}" git checkout "${barclamps[$bc]}"
    done
}

# Update tracking branches from the named remote,
# or origin if no remote is passed.
# Expects to be called within a specific repository
update_tracking_branches() {
    # Create tracking branches for any branches from this remote
    # that do not already exist.
    local remote=${1:-origin}
    while read p br; do
        [[ $br = refs/remotes/$remote* ]] || continue
        br=${br#refs/remotes/$remote/}
        [[ $br = HEAD ]] && continue
        [[ $br = personal/* ]] && continue
        [[ $br = pull-req* ]] && continue
        branch_exists "$br" && continue
        debug "$PWD: Creating tracking branch $br from remote $remote"
        git branch "$br" "$remote/$br"
    done < <(git show-ref)
}

update_all_tracking_branches() {
    local remote bc
    for remote in "${DEV_REMOTES[@]}"; do
        in_repo update_tracking_branches "$remote"
    done
    for bc in "$CROWBAR_DIR/barclamps/"*; do
        [[ -d $bc/.git || -f $bc/.git ]] || continue
        (cd "$bc"; update_tracking_branches origin)
    done
}

scrub_merged_pull_requests() {
    # $@ = branches to test for mergedness
    local br ref pull_req
    local -A to_remove pull_reqs heads
    git_config_has remote.personal.url || return
    while read ref br; do
        case $br in
            refs/heads/*)
                ref=${br#refs/heads/}
                heads[${ref//\//-}]+="$br ";;
            refs/remotes/personal/pull-req-*)
                ref=${br#refs/remotes/personal/pull-req-}
                ref=${ref#heads-}
                ref=${ref%-*}
                ref=${ref%-0}
                pull_reqs["$br"]="$ref";;
        esac
    done < <(git show-ref)
    [[ ${pull_reqs[*]} ]] || return 0
    for pull_req in "${!pull_reqs[@]}"; do
        ref="${pull_reqs[$pull_req]}"
        [[ ${heads[$ref]} ]] || continue
        for br in ${heads["$ref"]}; do
            branches_synced . "$br" "$pull_req" || \
                [[ $1 = '--all' ]] || continue
            to_remove["${pull_req#refs/remotes/personal/}"]="true"
            continue 2
        done
    done
    [[ ${!to_remove[*]} ]] || return
    git_push --delete personal "${!to_remove[@]}"
    git remote prune personal
}

# Fetch (but do not merge) updates from all our remotes, in both the
# main Crowbar repository and the barclamps.
fetch_all() {
    local remote remotes=() barclamp b branches=()
    dev_is_setup
    if [[ $@ ]]; then
        remotes=("$@")
    else
        remotes=("${DEV_REMOTES[@]}" personal)
    fi
    for remote in "${remotes[@]}"; do
        in_repo git_config_has "remote.$remote.url" || continue
        debug "Fetching from remote $remote:"
        debug "    Crowbar"
        in_repo git fetch -q "$remote" || continue
        branches=($(filter_branches_for_remote "$remote" \
            $(all_ordered_branches)))
        if [[ ${branches[@]} ]]; then
            in_repo update_tracking_branches "$remote"
            local -A touched_barclamps
            for b in "${branches[@]}"; do
                for barclamp in $(barclamps_from_branch "$b"); do
                    [[ ${touched_barclamps[$barclamp]} ]] && continue
                    debug "    Barclamp $barclamp"
                    in_barclamp "$barclamp" git fetch -q origin || \
                        die "Could not fetch updates for $barclamp"
                    in_barclamp "$barclamp" update_tracking_branches origin
                    touched_barclamps[$barclamp]="true"
                done
            done
            unset touched_barclamps
        else
            for barclamp in "$CROWBAR_DIR/barclamps/"*; do
                [[ -d $barclamp ]] || continue
                (   cd "$barclamp"
                    git_config_has "remote.${remote}.url" || continue
                    debug "    Barclamp ${barclamp##*/}"
                    git fetch -q "$remote"
                    update_tracking_branches origin
                )
            done
        fi
    done
    scrub_merged_pulls
}

scrub_merged_pulls() {
    in_repo scrub_merged_pull_requests "$@"
    for barclamp in "$CROWBAR_DIR/barclamps/"*; do
        [[ -d $barclamp ]] || continue
        in_barclamp "${barclamp##*/}" scrub_merged_pull_requests "$@"
    done
}

# Helper function for calling curl to talk to github.
curl_and_res() {
    local __r
    r="$(curl -n "$@" 2>/dev/null)"
    case $? in
        0) printf '%s' "$r";;
        7) echo "Unable to contact Github, please try again later." >&2
            return 1;;
        22) return 1;;
        *) echo "Curl reported error ${?}!." >&2
            return 1;;
    esac
}

# Fork a repository on Github.
github_fork() {
    # $1 = user to fork from
    # $2 = repo to fork
    curl_and_res -f -X POST \
        "https://api.github.com/repos/$1/$2/forks" >&/dev/null || \
        die "Could not fork $1/$2!"
}

github_url() {
    # $1 = repository name.
    # $@ = one of the following:
    #      -p = Use personal repository (based on DEV_GITHUB_ID) instead of
    #           dellcloudedge
    #      -a = Put github authentication info in the generated URL.
    local repo="$1" user="dellcloudedge"
    shift
    while [[ $1 ]]; do
        case $1 in
            -p) user="$DEV_GITHUB_ID";;
            *) die "Unknown option $1 to github_url";;
        esac
        shift
    done
    echo "https://github.com/${user}/$repo"
}

git_config_has() { git config --get "$1" &>/dev/null; }

get_repo_name() {
    local repo
    repo="$(git config --get remote.origin.url)" || \
        die "$PWD: Could not get the URL for the origin remote for this repo."
    repo="${repo##*:}"
    echo "${repo##*/}"
}

add_remote() {
    # $1 = name of the remote to add.
    # $2 = base part of the repo to add.
    git_config_has "remote.$1.url" && return 0
    local repo
    repo="$(get_repo_name)" || exit 1
    repo="$2/$repo"
    git ls-remote "$repo" refs/heads/master &>/dev/null || {
        debug "No git repo at $repo, skipping."
        return 0
    }
    git remote add "$1" "$repo"
    git fetch "$1"
}

rm_remote() {
    git_config_has "remote.$1.url" || return 0
    git remote rm "$1"
}

set_url_remote() {
    git_config_has "remote.$1.url" || return 0
    local repo
    repo="$(get_repo_name)" || exit 1
    repo="$2/$repo"
    git ls-remote "$repo" refs/heads/master &>/dev/null || {
        debug "No git repo at $repo, skipping."
        return 0
    }
    git set-url "$1" "$repo"
}

show_remote() {
    if [[ $1 ]]; then
        git remote show "$1"
    else
        git remote show
    fi
}

remote_wrapper() {
    # $1 = one of "add", "rm", "set-url", "show"
    # $2 = name of remote
    # $3 = base part of the remote URL.  Only used for add and set-url.
    local remote urlbase action bc
    remote="$2"
    urlbase="$3"
    case $1 in
        add) action=add_remote
            if ! in_repo \
                git_config_has "crowbar.remote.${remote}.urlbase"; then
                in_repo git config "crowbar.remote.${remote}.urlbase" "$3"
            fi;;
        rm) action=rm_remote
            if in_repo git_config_has "crowbar.remote.${remote}.urlbase"; then
                in_repo git config --unset "crowbar.remote.${remote}.urlbase"
            fi
;;
        set-url) action=set_url_remote
            if in_repo git_config_has "crowbar.remote.${remote}.urlbase"; then
                in_repo git config "crowbar.remote.${remote}.urlbase" "$3"
            else
                die "Cannot set-url for a remote your have not added."
            fi;;
        show) action=show_remote;;
        ''|help) die "Please pass one of add, rm, set-url, or show.";;
        *) die "Unknown action $1 for remote.";;
    esac
    for bc in "$CROWBAR_DIR/barclamps/"*; do
        [[ -d $bc ]] || continue
        debug "Barclamp: ${bc##*/}"
        in_barclamp "${bc##*/}" $action "$remote" "$urlbase"
    done
    debug "Crowbar:"
    in_repo $action "$remote" "$urlbase"
}

# Perform initial setup.  If you make any changes to this function, take
# care to make sure it stays idempotent.
setup() {
    local p remote release br head
    local -A touched_branches fetched_barclamps
    crowbar_is_clean || \
        die "Crowbar repo must be clean before trying to set things up!"
    # Make sure we have Github login credentials as the very first thing.
    [[ $DEV_GITHUB_ID ]] || {
        local DEV_GITHUB_PASSWD
        read -p "Enter your Github username: " DEV_GITHUB_ID
        curl_and_res -f \
            "https://api.github.com/users/$DEV_GITHUB_ID" &>/dev/null || \
            die "Could not verify that $DEV_GITHUB_ID is a valid Github user.."
        while [[ $p != $DEV_GITHUB_PASSWD || ! $p ]]; do
            [[ $p ]] && echo "Passwords did not match, try again."
            read -s -p "Enter your Github password: " DEV_GITHUB_PASSWD
            echo
            read -s -p "Enter your Github password again: " p
            echo
        done
        curl_and_res -f -u "$DEV_GITHUB_ID:$DEV_GITHUB_PASSWD" \
            https://api.github.com/user &>/dev/null || {
            echo "Unable to authenticate as Github user $DEV_GITHUB_ID." >&2
            die "Please try again when you have Github access."
        }
        for mach in github.com api.github.com; do
            grep -q "^$mach" "$HOME/.netrc" &>/dev/null && continue
            printf "\nmachine %s login %s password %s\n" \
                "$mach" "$DEV_GITHUB_ID" "$DEV_GITHUB_PASSWD" >> "$HOME/.netrc"
        done
        chmod 600 "$HOME/.netrc"
        printf "DEV_GITHUB_ID=%q\n" "$DEV_GITHUB_ID" >> "$HOME/.build-crowbar.conf"
    }
    # We have a baked-in assumption that Github is our origin, and that
    # any repositories that are named the same thing as a repository from
    # dellcloudedge is in fact a fork of a dellcloudedge repo.
    # We should not make that assumption at some point in the future.
    echo "Finding Github repos..."
    local repos=($(show_github_repos))
    if ! is_in crowbar "${repos[*]}"; then
        echo "Creating your fork of Crowbar on Github."
        github_fork dellcloudedge crowbar || \
            die "Unable to create your fork of Crowbar."
    fi
    if ! in_repo git_config_has remote.origin.pushurl; then
        echo "Creating a push URL for crowbar on Github"
        in_repo git remote set-url --push origin \
            "$(github_url crowbar.git)"
    fi
    if ! in_repo git_config_has remote.personal.url; then
        echo "Adding remote for personal fork of crowbar on Github."
        in_repo git remote add personal \
            "$(github_url crowbar.git -p)"
        in_repo git fetch -q personal || \
            die "Cannot fetch repository info for your Crowbar fork on Github!"
        in_repo git remote set-head -a personal
    fi
    in_repo git config branch.autosetupmerge true &>/dev/null
    in_repo git config crowbar.backup.method per-remote
    head_release="$(current_release)"
    # Set up the rest of our upstream remotes.
    for remote in "${DEV_REMOTES[@]}"; do
        # Add a remote if we don't already have one.
        if [[ ${DEV_REMOTE_SOURCES[$remote]} ]] && \
            ! in_repo git_config_has "remote.$remote.url"; then
            in_repo git remote add "$remote" \
                "${DEV_REMOTE_SOURCES[$remote]}/crowbar.git"
        fi

        in_repo git fetch -q "$remote" || \
            die "Unable to fetch remote references for $remote"

        if ! in_repo git_config_has "crowbar.backup.$remote.method"; then
            case $remote in
                origin)
                    in_repo git config crowbar.backup.$remote.method remote
                    in_repo git config crowbar.backup.$remote.remote personal;;
                *)
                    in_repo git config crowbar.backup.$remote.method prefix
                    in_repo git config crowbar.backup.$remote.remote "$remote"
                    in_repo git config crowbar.backup.$remote.prefix \
                        "personal/$DEV_GITHUB_ID";;
            esac
        fi

        [[ $head ]] || head=$(in_repo git symbolic-ref HEAD) || \
            die "HEAD does not point at a branch, cannot finish setup."

        in_repo update_tracking_branches "$remote"
        for release in $(show_releases); do
            switch_release "$release"
            checkout master
            for b in $(filter_branches_for_remote "$remote" \
                $(branches_for_release)); do
                in_repo quiet_checkout "$b" || \
                    die "Cannot checkout $b"
                for bc in $(barclamps_from_branch "$b"); do
                    debug "$release: $remote: $b: $bc"
                    in_repo git_config_has "submodule.barclamps/$bc.url" || {
                        clone_barclamp "$bc"
                        fetched_barclamps["$bc"]="true"
                    }
                    repo="$(get_repo_cfg "submodule.barclamps/$bc.url")"
                    repo="${repo##*/}"
                    repo="${repo##*:}"
                    repo="${repo%.git}"
                    [[ ${fetched_barclamps[$bc]} ]] || {
                        in_barclamp "$bc" git fetch origin
                        fetched_barclamps["$bc"]="true"
                    }
                    in_barclamp "$bc" update_tracking_branches origin
                    in_barclamp "$bc" git_config_has \
                        crowbar.backup.origin.method && continue
                    if [[ $remote = origin ]]; then
                        if ! is_in "$repo" "${repos[*]}"; then
                            github_fork dellcloudedge "$repo" || \
                                die "Could not create a personal fork of $repo"
                        fi
                        if ! in_barclamp "$bc" \
                            git_config_has remote.personal.url; then
                            in_barclamp "$bc" git remote add personal \
                                $(github_url "$repo" -p)
                            in_barclamp "$bc" git fetch -q personal || \
                                die "Cannot fetch repository info for your fork of $repo."
                            in_barclamp "$bc" git remote set-head -a personal
                        fi
                        if ! in_barclamp "$bc" \
                            git_config_has remote.origin.pushurl; then
                            in_barclamp "$bc" git remote set-url --push origin \
                                "$(github_url $repo)"
                        fi
                        in_barclamp "$bc" git config \
                            crowbar.backup.origin.method remote
                        in_barclamp "$bc" git config \
                            crowbar.backup.origin.remote personal
                    else
                        in_barclamp "$bc" git config \
                            crowbar.backup.origin.method prefix
                        in_barclamp "$bc" \
                            git config crowbar.backup.origin.prefix \
                            "personal/$DEV_GITHUB_ID"
                    fi
                    in_barclamp "$bc" git config branch.autosetupmerge true
                done
            done
        done
    done
    [[ $head_release != $(current_release) ]] && switch_release "$head_release"
    [[ $head ]] && quiet_checkout "${head#refs/heads/}"
    for bc in "$CROWBAR_DIR/barclamps/"*; do
        (   cd "$bc"
            [[ -d .git || -f .git ]] || continue
            quiet_checkout "${DEV_RELEASE_PREFIX}master"
        )
    done
    in_repo git config crowbar.dev.version "$DEV_VERSION"
}

# Test repository $1 to see if commit $2 is in sync with $3.
# In this case, "in sync" is defined as:
#  * $2 and $3 point at the same commit, or
#  * There are no commits in the set of all commits reachable from $3 that
#    are not also reachable from $2.
branches_synced() {
    # $1 = repository to operate in
    # $2 = local branch to test
    # $3 = remote branch to test
    [[ -d $1/.git || -f $1/.git ]] || \
        die "branches_synced: $1 is not a git repo"
    [[ $VERBOSE2 ]] && echo "Checking to see if out of sync: $2 $3"
    (cd "$1"; git rev-parse --verify -q "$2" &>/dev/null) || \
        return 1
    (cd "$1"; git rev-parse --verify -q "$3" &>/dev/null) || \
        return 1
    # $2 and $3 resolve to the same commit, they are in sync.
    (cd "$1"; [[ $(git rev-parse "$2") = $(git rev-parse "$3") ]] ) && return 0
    # Test to see if there are any commits in $3 that are not
    # reachable from $2.  If there are, then the branches are not synced.
    (cd "$1"; [[ ! $(git rev-list "$2..$3") ]] ) && return 0
    return 1
}

# Back up our current commits to local branches in a barclamp that:
#  * Have a matching branch at origin, or
#  * Have a matching remote at $1.
backup_to_remote() {
    local remote=$1 branch branches=()
    shift
    git remote prune "$remote"
    for branch in "$@"; do
        if [[ $branch = ':'* && $(git rev-parse --verify -q \
            "refs/remotes/$remote/${branch#:}") ]]; then
            branches+=("$branch")
        elif branch_exists "$branch" && \
            [[ $(git rev-parse --verify -q "refs/remotes/$remote/$branch") != \
            $(git rev-parse --verify -q "refs/heads/$branch") ]]; then
            branches+=("$branch")
        fi
    done
    if [[ $branches ]]; then
       if [[ ! $PWD =~ /barclamps/ ]]; then
           debug "Crowbar: Backing up ${branches[*]}"
       else
           debug "Barclamp ${PWD##*/}: Backing up ${branches[*]}"
       fi
       git_push -qf "$remote" "${branches[@]}"
    fi
}

# Back up our current commits to local branches in a barclamp by force-creating
# a new branch named personal/$DEV_GITHUB_ID/$branch for each branch, and then
# force-pushing the newly created or updated branch back to the origin remote.
backup_with_prefix () {
    local remote="$2" prefix="$1" branches=() branch ref
    [[ $remote && $prefix ]] || \
        die "generic_backup: Must pass a remote and a prefix."
    shift 2
    local remote_prefix="refs/remotes/$remote/$prefix"
    [[ $(git symbolic-ref HEAD) = "refs/heads/$prefix"/* ]] && \
        die "prefix_backup: $prefix branch checked out, cannot proceed."
    git remote prune "$remote"
    for branch in "$@"; do
        if [[ $branch = ':'* && $(git rev-parse --verify -q \
            "$remote_prefix/${branch#:}") ]]; then
            branches+=(":$prefix/${branch#:}")
            continue
        fi
        branch_exists "$branch" || continue
        if [[ $branch = ${prefix}* ]]; then
            debug "Cleaning up ${branch#refs/heads}"
            git branch -D "${branch#refs/heads}"
            git_push -q "$remote" ":${branch#refs/heads}"
            continue
        fi
        [[ $(git rev-parse --verify -q "$remote_prefix/$branch") && \
            $(git rev-parse "$remote_prefix/$branch") = \
            $(git rev-parse "refs/heads/$branch") ]] && continue
        branches+=("$branch:$prefix/$branch")
    done
    if [[ $branches ]]; then
        if [[ ! $PWD =~ /barclamps/ ]]; then
            debug "Crowbar: Backing up ${branches[*]%%:*}"
        else
            debug "Barclamp ${PWD##*/}: Backing up ${branches[*]%%:*}"
        fi
        git_push -qf "$remote" "${branches[@]}"
    fi
}

branches_to_backup_to_remote() {
    # $1 = "backup" remote
    # $2 = "upstream" remote
    # $@ = branches to exclude from consideration
    # Echos each branch that should be backed up via this method.
    local target="$1" upstream="$2" br ref
    local -A ignore
    shift 2
    [[ $upstream && $target && $upstream != $target ]] && \
        git_config_has "remote.$upstream.url" && \
        git_config_has "remote.$target.url" || \
        die "branches_to_remote: Invalid branch $upstream or $target."
    for br in "$@"; do
        ignore["$br"]="true"
    done
    # Push branches that have been pushed to personal in the past
    while read ref br; do
        [[ $br = */HEAD ]] && continue
        br="${br#refs/heads/}"
        if [[ ${ignore[$br]} = true ]]; then
            # Skip branches we were asked to ignore.
            continue
        elif [[ $(remote_for_branch ${br##*/}) = $upstream ]]; then
            # Back up branches that we "have" remotes for.
            echo "$br"
        elif ! (git rev-parse --verify -q "refs/remotes/$target/$br" || \
            git rev-parse --verify -q "refs/remotes/$upstream/$br") &>/dev/null
        then
            # If we do not have a ref for this branch on the personal remote
            # or on the origin remote, this branch should not be backed up.
            continue
        else
            # Back it up.
            echo "$br"
        fi
    done < <(git show-ref --heads)
    # Find branches that have been removed locally, and make sure their
    # backups have also been removed.
    while read ref br; do
        [[ $br = */HEAD ]] && continue
        [[ $br = refs/remotes/$target/* ]] || continue
        branch_exists "${br#refs/remotes/$target/}" && continue
        [[ $br = refs/remotes/$target/pull-req* ]] && continue
        echo ":${br#refs/remotes/$target/}"
    done < <(git show-ref)
}

branches_to_backup_to_prefix() {
    local prefix="$1" remote="$2" br ref b
    local -A ignore
    shift 2
    [[ $remote && $prefix ]] && \
        git_config_has "remote.$remote.url" || \
        die "generic_backup: Must pass a remote and a prefix."
    for br in "$@"; do
        ignore["$br"]="true"
    done
    local head_prefix="$prefix"
    local remote_prefix="$remote/$prefix"
    [[ $(git symbolic-ref HEAD) = "refs/heads/$head_prefix"/* ]] && \
        die "prefix_backup: $prefix branch checked out, cannot proceed."
    while read ref br; do
        [[ $br = */HEAD ]] && continue
        br="${br#refs/heads/}"
        if [[ $br = personal/* ]]; then
            debug "Deleting unneeded local tracking branch $br"
            git branch -D "$br"
            if [[ $br = $prefix/personal/* ]]; then
                debug "Pruning unneeded branch $br on $remote"
                git_push -q "$remote" ":${br}"
            fi
            continue
        elif [[ ${ignore[$br]} = true ]]; then
            continue
        elif [[ $(remote_for_branch ${br##*/}) = $remote ]]; then
            # Back up branches that we "have" remotes for.
            echo "$br"
        elif [[ $(git rev-parse --verify -q "$remote_prefix/$br") && \
            $(git rev-parse "$remote_prefix/$br") = \
            $(git rev-parse "refs/heads/$br") ]]; then
            continue
        else
            echo "$br"
        fi
    done < <(git show-ref --heads)
    # Kill remote personal branches we no longer want to back up.
    while read ref br; do
        [[ $br = */HEAD ]] && continue
        [[ $br = refs/remotes/$remote_prefix/* ]] || continue
        branch_exists "${br#refs/remotes/$remote_prefix/}" && continue
        [[ $br = refs/remotes/$remote_prefix/pull-req* ]] && continue
        echo ":${br#refs/remotes/$remote_prefix/}"
    done < <(git show-ref)
}

get_backup_var() {
    local res=''
    res=$(git config --get "crowbar.backup.$remote.$1") || \
    res=$(git config --get "crowbar.backup.$1") || \
        return 1
    echo "$res"
}

# Back up any local commits that are not already present on our upstreams,
# or that have not already been backed up.
backup_repo() {
    local bc branch remote branch_get_func branch_backup_func
    local -A branches touched_branches
    local backup_method target_remote target_method target_prefix
    local backup_method remotes=()
    [[ $1 ]] && remotes=("$@") || remotes=(origin)
    for remote in "${remotes[@]}"; do
        git_config_has "remote.$remote.url" || \
            die "Cannot back up remote $remote."
        backup_method=$(get_backup_var method) || \
            die "No backup method, have you run $0 setup?"
        case $backup_method in
            remote) backup_remote=$(get_backup_var remote) || \
                die "No backup remote, have you run $0 setup?"
                branch_get_func="branches_to_backup_to_remote $backup_remote"
                branch_backup_func="backup_to_remote $backup_remote"
                ;;
            prefix) backup_prefix=$(get_backup_var prefix) || \
                die "No backup prefix, have you run $0 setup?"
                branch_get_func="branches_to_backup_to_prefix $backup_prefix"
                branch_backup_func="backup_with_prefix $backup_prefix $remote"
                ;;
            *) die "Unknown backup method $backup_method!";;
        esac
        [[ $(type -t ${branch_get_func%% *}) = function ]] || \
            die "Don't know how to get branches to backup for $backup_method."
        [[ $(type -t ${branch_backup_func%% *}) = function ]] || \
            die "Don't know how to back up branches for $backup_method"
        for branch in $($branch_get_func "$remote" ${branches[@]}); do
            branches["$remote"]+=" $branch"
        done
        if [[ ${branches[$remote]} ]]; then
            $branch_backup_func ${branches["$remote"]}
        fi
    done
}

backup_everything() {
    local bc remote branches=() branch
    local remotes=("${DEV_REMOTES[@]}")
    local -A touched_bcs
    dev_is_setup
    [[ $@ ]] && remotes=("$@")
    for remote in "${remotes[@]}"; do
        # Back up all the barclamps that are references as submodules for
        # branches that this remote is "authoritative" for.
        for branch in $(filter_branches_for_remote "$remote" \
            $(all_ordered_branches)); do
            for bc in $(barclamps_from_branch "$branch"); do
                [[ ${touched_bcs[$bc]} ]] && continue
                is_barclamp "${bc}" || continue
                in_barclamp "${bc}" backup_repo
                touched_bcs[$bc]="true"
            done
        done
        in_repo backup_repo "$remote" || \
            die "Could not back up Crowbar!"
    done
}

merge_or_rebase_from_remote() {
    # $1 = remote
    # $2 = local branch
    local remote branch rebase_temp
    remote="$1" branch="$2" rebase_temp="$branch-rebase"
    git rev-parse --verify -q "$remote/$branch" &>/dev/null || return 0
    branches_synced "." "refs/heads/$branch" "refs/remotes/$remote/$branch" && return 0
    [[ $head ]] || head=$(git symbolic-ref HEAD) || \
        head=$(git rev-parse HEAD) || die "$repo: Cannot find head commit."
    quiet_checkout "$branch" || die "$remote: Unable to checkout $branch!"
    git branch -f --no-track "$rebase_temp" "$branch"
    debug "$repo: Merging $remote/$branch into $branch"
    git merge -q "$remote/$branch" || {
        git merge --abort
        die "$repo: Unable to merge $remote/$branch into $branch, aborted"
    }
    if [[ $allow_remote_rebase = true ]] && \
        is_in "$remote" "${DEV_ALL_REMOTES[*]}"; then
        if ! git rebase -p -q "$remote/$branch" "$rebase_temp" &>/dev/null; then
            git rebase --abort
            quiet_checkout "$branch"
        elif ! git diff --exit-code "$branch" "$rebase_temp"; then
            quiet_checkout "$branch"
        else
            debug "$repo: Rebased version of $branch is identical to merged version."
            debug "$repo: Using the rebased version instead."
            quiet_checkout "$branch"
            git reset --hard "$rebase_temp"
        fi
    fi
    git branch -D "$rebase_temp" &>/dev/null
}

sync_branch_from_personal() {
    # $1 = remote
    # $2 = local branch
    local personal="refs/remotes/$1/personal/$DEV_GITHUB_ID/$2"
    git rev-parse --verify -q "$personal"&>/dev/null || return 0
    branches_synced "." "$personal" "refs/heads/$2" && return 0
    [[ $head ]] || head=$(git symbolic-ref HEAD) || \
        head=$(git rev-parse HEAD) || die "$repo: Cannot find head commit."
    quiet_checkout "$2" || die"$1: Unable to checkout $2!"
    git merge -q "$personal" || {
        git merge --abort
        die "$repo: Unable to merge $1/$2 into $2, aborted"
    }
}

# Handle merges across releases.  Most of the ugliness here is around making
# sure that we don't get merge conflicts due to different barclamp submodule
# updates, which we don't care about locally.
merge_releases() {
    # $@ = releases to merge.
    local rel ref branch br mode t bc
    local cur_rel="$(current_release)"
    local -A our_barclamps their_barclamps
    for branch in $(ordered_branches); do
        branch_exists "$branch" || continue
        br="${branch##*/}"
        quiet_checkout "$branch" || \
            die "Could not checkout $branch in merge_releases!"
        # Save our current barclamp references to be restored later.
        if [[ -d barclamps ]]; then
            while read mode t ref bc; do
                [[ $mode = '160000' && $t = 'commit' ]] || continue
                our_barclamps["$bc"]="$ref"
            done < <( git ls-tree -r HEAD barclamps)
        fi
        for rel in "$@"; do
            [[ $rel ]] || continue
            [[ $rel != $cur_rel ]] || continue
            is_in "$rel" "$(show_releases)" || continue
            local from_prefix="$(branch_prefix "$rel")"
            branch_exists "${from_prefix}$br" || continue
            if [[ -d barclamps ]]; then
                local do_commit=''
                # Find all the common barclamps that point at different
                # submodule references.  Make the current branch point at the
                # same refs as the to-be-merged branch to avoid merge conflicts
                # that we really don't care about locally anyways.
                while read mode t ref bc; do
                    [[ ${our_barclamps[$bc]} && \
                        ${our_barclamps[$bc]} != $ref ]] || continue
                    git update-index --cacheinfo 160000 "$ref" "$bc"
                    do_commit=true
                done < <(git ls-tree -r "${from_prefix}$br" barclamps)
                [[ $do_commit ]] && \
                    git commit -m "Eschew barclamp merge conflicts."
                unset do_commit
            fi
            git merge -q "${from_prefix}$br" || {
                echo "Could not automatically merge.  Dropping to a shell."
                echo "If you want to abort this merge, exit the shell with 'exit 1'"
                /bin/bash
            } || {
                git merge --abort
                die "$repo: Merge of $br from $rel into $cur_rel failed."
            }
        done
        if [[ -d barclamps ]]; then
            # Unwind submodule updates for barclamps.  This leaves them
            # out of sync from where they really should be at this point,
            # but the policy of the dev tool is that all "real" barclamp
            # submodule reference updates happen at pull-requests-gen time.
            while read mode t ref bc; do
                [[ ${our_barclamps[$bc]} && \
                    ${our_barclamps[$bc]} != $ref ]] || continue
                ref="${our_barclamps[$bc]}"
                git update-index --cacheinfo 160000 "$ref" "$bc"
                do_commit=true
            done < <(git ls-tree -r HEAD barclamps)
            [[ $do_commit ]] && {
                git commit -m "Move barclamp submodule refs back."
                debug "Submodules updated for $branch in Crowbar."
                debug "Builds with --exact will be broken until this branch has been through a pull request."
            }
            unset do_commit
        fi
    done
}

# Merges in changes into all local branches from their upstreams.
# Assumes that upstream commits have already been fetched from the proper
# remotes by running dev fetch.
sync_repo() (
    local branch head b rel bc remote ref personal repo="$1"
    shift
    # $repo = dir to CD to initially.
    # Assumes that remote has already been fetched.
    cd "$repo"
    # Repo is not clean, we will refuse to merge in any case.
    git_is_clean || exit 1
    # Merge upstream branches from all remotes, but only if the branch
    # is listed in DEV_REMOTE_BRANCHES for that remote,
    # unless $remote is actually "origin"
    [[ $head ]] || head=$(git symbolic-ref HEAD) || \
        head=$(git rev-parse HEAD) || die "$repo: Cannot find head commit."
    while read ref branch; do
        branch=${branch#refs/heads/}
        remote="$(remote_for_branch "$branch")" || continue
        git_config_has "remote.$remote.url" || continue
        merge_or_rebase_from_remote "$remote" "$branch"
    done < <(git show-ref --heads)
    if [[ $(git rev-parse --verify -q HEAD) != \
        $(git rev-parse --verify -q $head) ]]; then
        quiet_checkout "${head#refs/heads/}"
    fi
    if [[ $@ ]]; then
        merge_releases "$@"
        quiet_checkout "${head#refs/heads/}"
    fi
    return 0
)

# Recursivly merge all changes from a given branch into its children, if any.
# Parent -> child relations are defined by the structure of DEV_BRANCHES.
ripple_changes_out() {
    # $1 branch to ripple changes from. Changes will be rippled to all
    # children of $1.
    local parent="$1" child
    in_repo git rev-parse --verify -q "$parent" &>/dev/null || \
        die "ripple_changes_out: $parent is not a branch in Crowbar!"
    for child in $(child_branches "$parent"); do
        in_repo git rev-parse --verify -q "$parent" &>/dev/null || \
            die "ripple_changes_out: $child is not a branch in Crowbar!"
        if ! branches_synced "$CROWBAR_DIR" \
            "refs/heads/$child" "refs/heads/$parent"; then
            [[ $(in_repo git symbolic-ref HEAD) = refs/heads/$child ]] || \
                in_repo quiet_checkout "$child"
            debug "Merging $parent into $child"
            in_repo git merge -s recursive -X theirs -q "$parent" || \
                die "Merge $parent into $child branch of Crowbar failed."
        fi
        ripple_changes_out "$child"
    done
}

# Merge all changes from our upstreams for all barclamps and the main Crowbar
# repository, and then update the branches for the current release according
# to the branch structure defined in DEV_BRANCHES.
sync_everything() {
    local unsynced_barclamps=()
    local b u head res=0 ref branch rel allow_remote_rebase=true
    crowbar_is_clean || exit 1
    # Do barclamps first.
    for b in "$CROWBAR_DIR/barclamps/"*; do
        debug "Syncing ${b##*/}"
        if ! sync_repo "$CROWBAR_DIR/barclamps/${b##*/}" "$@"; then
            unsynced_barclamps+=("${b##*/}")
            continue
        fi
    done
    # Finished with barclamps, now for crowbar.
    allow_remote_rebase=false
    debug "Syncing crowbar"
    [[ $head ]] || head=$(git symbolic-ref HEAD) || \
        head=$(git rev-parse HEAD) || die "$repo: Cannot find head commit."
    sync_repo "$CROWBAR_DIR" "$@" || \
        die "Could not sync Crowbar with origin branches"

    # Now for the branch-rippling merges of doom
    for branch in $(root_branches); do
        ripple_changes_out "$branch"
    done
    if [[ $(git rev-parse --verify -q HEAD) != \
        $(git rev-parse --verify -q $head) ]]; then
        quiet_checkout "${head#refs/heads/}"
    fi
    if [[ $unsynced_barclamps ]]; then
        echo "Unable to sync origin with current master in:" >&2
        echo "  ${unsynced_barclamps[*]}"
        res=1
    fi
    [[ $res = 0 ]] && return 0
    echo
    echo "Please fix things up and rerun sync."
    return 1
}

dev_short_help() {
    cat <<EOF
$0: Development helper for Crowbar

setup:              Sets up a Crowbar checkout for use with dev.
is_clean:           Test to see if all work is committed.
fetch:              Fetch updates from configured upstream repositories.
remote:             Manage remotes across all dellcloudedge repositories.
backup:             Back up changes without merging them into upstream.
sync:               Synchronize fetched updates with the local repos.
push:               Unconditionally push a branch to your personal repos.
pull-requests-prep: Prepare to issue pull requests.
pull-requests-gen:  Issue pull requests.
release:            Show the current release or feature you are on.
releases:           Show all releases and features in your local repos.
branches:           Show the branches in the current release.
switch:             Switch to a different release.
checkout:           Check out a branch in the current release.
build:              build Crowbar.
cut_release:        Cut a new release from the current one.
new-feature:        Create a new feature bundle from the current release.
erase-feature:      Forget about branches for a feature you are not working on.
find-parent:        Find the closest parent of a release or feature.
reset-release:      Resets a release to upstream or your last backup.
scrub-merged-pulls: Scrub merged pull request branches.

For more detailed help, use the "help" command or read README.dev-and-workflow.
EOF
}

dev_help () {
    less <<EOF
$0: Development helper for Crowbar.

Command line options:

  setup -- Sets up your local Crowbar repositories for working with the
           new Github regime.  This command will prompt for your Github
           login information, make sure you have local copies of all the
           barclamp repos that Crowbar references checked out, create personal
           forks of all the crowbar repos from the dellcloudedge account on
           github, and create the appropriate remotes needed for day-to-day
           operation.

  is_clean -- Check to see if the barclamps have everything committed
              with no untracked files, and check to see if the main
              Crowbar repository is clean while ignoring submodule references.

  fetch -- Fetch all changes from the dellcloudedge Crowbar repositories.
           Does not try to merge any changes into your local repository.
           You can run a fetch at any time without disturbing your working
           code, provided you have network connectivity.
           If you pass the name of a remote, fetch will try to fetch changes
           from that remote in the main Crowbar repository and in each of the
           barclamps

  remote -- Manage remotes across all dellcloudedge repositories.  It has the
            following subcommands:
            add <remote> <urlbase> : The add subcommand adds a new remote to
                the Crowbar repositories.
            rm <remote> : The rm subcommand removes an already-existing remote
                from the Crowbar repositories.
            set-url <remote> <urlbase> : The set-url subcommands allows you to
                give an existing remote a new URL in all the subrepositories.
            show <remote> : The show subcommand shows remote information for
                the named remote in all the Crowbar repositories.

           Note that <urlbase> is the URL got will use without the actual
           repository name.  dev assumes that the new remote uses the same
           repository name as the origin remote does, and things will fail
           badly if this assumption is violated.

  backup -- Push any locally committed changes in any repositories that were
            initially forked from dellcloudedge into your personal Github forks.
            You can run a backup at any time without disturbing your working
            code, provided you have network connectivity.

  sync -- Merge any changes that have been fetched into the current
          repositories.  dev is_clean should exit without any messages before
          running this command.  If you pass an argument to sync, it will
          interpret that argument as a release or feature name and try to
          merge any changes in common branches from that release.

  push -- Unconditionally push a branch (or branches) to your crowbar Github
          fork.  Any arguments are interpreted as branch names to push, and
          if there are no arguments it pushes the branch you are currently on.
          Any branches pushed using this command will automatically be backed
          up when dev backup is run as well.

  pull-requests-prep -- Fetches, Syncs, and backs up all changes, then figures
                        out the set of barclamps and crowbar branches that
                        need to have pull requests created.  The output is a
                        command line that canbe copied and executed.

  pull-requests-gen -- Creates a set of pull requests with similar ids and
                       links based upon the barclamps dependency trees.  These
                       will be automatically sent to Github for processing and
                       review by the Dell review team.

  release -- Shows the current release that dev is operating on.

  releases -- Lists the releases to choose from.

  branches -- Shows the branches that are part of the specified release,
              or the current release if no release is specified.

  switch -- Change current release to the specified release, or the current
            release if no release name was passed.  This has the side effect
            of making sure that all the barclamps are on the proper branch for
            that release. dev switch will also set any barclamps that are not
            used in the new branch to an empty branch.

  checkout -- Change branch but stays in the release context if possible.
              Checkout will ensure that any barclamps that are ont being used
              by the new branch are set to an empty branch.

  build -- Set up the local trees and build a crowbar ISO.  Parameters:
           --os = operating system to stage Crowbar on to.
           --release = Release of Crowbar to build.
           --branch = Branch withina release of Crowbar to build
           --exact = If present, dev will run git submodule update after
                     processing the --release and --branch options, and the
                     --no-cache-update and --no-metadata-update parameters will
                     be passed to build_crowbar.sh.
                     If not present, the submodules will be checked out to the
                     appropriate master branch for the release.
           Any other parameters will be passed unchanged to build_crowbar.sh.
           See README.build for more information on building Crowbar.

  cut_release -- DO NOT USE UNLESS YOU KNOW WHAT YOU ARE DOING! Makes a new set
                 of branches and barclamp branches from the current release into
                 the new named release.  Must provide a unique new name.

  new-feature -- Create a new set of feature branches.  Must provide a unique
                 new name, and you must be in the development release when you
                 run this command.  Internally, features are implemented as
                 releases in the feature/ namespace, so all the other release
                 manipulation commands will work with them.

  erase-feature -- Erase feature branches created with new-feature.
                   This command is intended to be run after a feature has been
                   merged into the main devleopment stream to avoid cluttering
                   up the output of the git branch command.  It will fail if
                   the feature has not been merged into the development release.

  find-parent -- Find the parent of a release or feature based on the which
                 of the releases have the shortest merge distance from the
                 release passed to find-parent, so it is possible for more than
                 one release to be considered to be the parent. If that turns
                 out to be the case, find-parent wil ask you to disambiguate.

  reset-release -- Reset a release or feature to either the last pull from
                   upstream or your last backup.  Paremeters:
                   --release: Release to reset.  Defaults to current.
                   --target: Either "upstream" or "backup".
                             Defaults to "backup".
                   --skip-master: If set, will skip resetting the master branch
                                  in the release and any barclamps that the
                                  master branch pulls in.  Is automatically set
                                  if --release is not specified.
                   --skip-barclamps: Skip resetting the the barclamps for the
                                     release.

  scrub-merged-pulls -- Delete any tracking branches created as placeholders
                        for pull requests.  Without any options, this just
                        scrubs tracking branches for pull requests that have
                        already been merged.  If --all is passed as an option,
                        then all pull request tracking branches will be deleted.
EOF
}

# Tests to see if the given branch in a repo needs a pull request.
branch_needs_pull_req() {
    # $1 = branch
    local upstream=''
    if [[ $1 = feature/* ]]; then
        upstream="origin/${1##*/}"
    else
        upstream="origin/$1"
    fi
    git rev-parse --verify -q "$upstream" &>/dev/null || return 1
    branches_synced '.' "refs/remotes/$upstream" \
        "refs/heads/$1" && return 1
    return 0
}

# Make sure everything is up to date, and then figure out what barclamps
# and branches need pull requests on Github.  Once we have that figured out,
# print out a command line that can be used by dev pull-requests-gen to
# actually generate the pull requests.
pull_requests_prep() {
    crowbar_is_clean || exit 1
    fetch_all && sync_everything || \
        die "Unable to prepare for pull requests"
    local -A barclamps branches_to_push
    local barclamps_to_push=()
    local branch bc
    for branch in ${DEV_REMOTE_BRANCHES["origin"]}; do
        branch="${DEV_BRANCH_PREFIX}$branch"
        in_repo branch_exists "$branch" || continue
        for bc in $(barclamps_from_branch "$branch"); do
            in_barclamp "$bc" branch_needs_pull_req \
                "${DEV_BRANCH_PREFIX}master" || continue
            barclamps_to_push+=("$bc/${DEV_BRANCH_PREFIX}master")
            branches_to_push["$branch"]="true"
        done
        [[ ${branches_to_push["$branch"]} ]] && continue
        in_repo branch_needs_pull_req "$branch" || continue
        branches_to_push["$branch"]="true"
    done
    [[ ${!branches_to_push[*]} || ${barclamps_to_push} ]] || {
        echo "Everything up to date, no pull requests are possible."
        return 0
    }
    echo "Barclamps to update: ${barclamps_to_push[*]-(none)}"
    echo -n "Branches to update: "
    [[ ${!branches_to_push[*]} ]] && echo "${!branches_to_push[*]}" || \
        echo "(none)"
    echo "Command to generate pull requests:"
    echo -n "  $0 pull-requests-gen"
    [[ ${!branches_to_push[*]} ]] && \
        echo -n " --branches ${!branches_to_push[*]}"
    [[ ${barclamps_to_push[*]} ]] && \
        echo -n " --barclamps ${barclamps_to_push[*]}"
    echo
}

# Actaully generate a pull request by using make_pull_request to
# create the JSON blob that github needs, and then posting that to the
# right URL at Github.
do_pull_request() {
    # $1 = url to POST to
    # rest of args passed verbatim to make_pull_request helper.
    local posturl="$1"
    local -A res
    shift
    if [[ $DEBUG ]]; then
        make_pull_request "$@"
        return
    fi
    . <(make_pull_request "$@" | \
        curl_and_res -X POST --data @- \
        -H "Content-Type: application/vnd.github.beta.raw+json" \
        "$posturl" |parse_yml_or_json - res 2>/dev/null) || {
        echo "Pull request to $posturl with following params failed:"
        echo "$@"
        echo "Please delete the ones that succeeded and try again."
        exit 1
    }
    if [[ ${res['number']} && ${res['html_url']} ]]; then
        printf "Pull request %s created (%s)\n" \
            "${res['number']}" "${res['html_url']}"
    else
        echo "Pull request to $posturl with following params failed:"
        echo "$@"
        echo "Please delete the ones that succeeded and try again."
        exit 1
    fi
}

# Get the diffstat from the origin branch of the branch passed,
# or print an error message if there is no origin.
diffstat_from_origin() {
    local upstream=''
    if [[ $1 = feature/* ]]; then
        upstream="origin/${1##*/}"
    else
        upstream="origin/$1"
    fi
    if git rev-parse --verify -q "$upstream" &>/dev/null; then
        git diff --stat "$upstream" "$1"
    else
        echo "No origin to generate diffstat"
    fi
}

git_ref() {
    # $1 = branch
    printf "%s-%s" "${1//\//-}" "$(git show-ref --hash=10 "refs/heads/$1")"
}

# Make pull requests based on the command line args passed.
# These should follow the command line arguments that
# pull_requests_prep generated.
pull_requests_gen() {
    # $@ = options to parse
    dev_is_setup
    local -A barclamps branches barclamp_branches bc_pulls br_pulls refs
    local bc br bcr title body option bc_name head
    local prc=0 n=1
    body="$(mktemp /tmp/crowbar-pull-req-XXXXXXXX)"
    if [[ $DEBUG ]]; then
        title="Test"
        echo "test" >> "$body"
    else
        echo "Enter a title for this pull request series."
        echo "After you have entered a title, an editor will open, and you can"
        echo "enter anything you want for the body of the pull requests."
        read -p "Title: " title
        if [[ $EDITOR ]]; then
            $EDITOR "$body"
        else
            nano "$body"
        fi
    fi
    # Parse our options and validate them.
    while [[ "$1" ]]; do
        case $1 in
            --branches)
                shift
                while [[ $1 && $1 != '--'* ]]; do
                    br="$1"
                    shift
                    in_repo branch_exists "$br" || \
                        die "$br is not a branch in Crowbar!"
                    branches["$br"]="true"
                done;;
            --barclamps)
                shift
                while [[ $1 && $1 != '--'* ]]; do
                    bc="${1%%/*}"
                    br="${1#*/}"
                    [[ $bc = $br ]] && br="${DEV_BRANCH_PREFIX}master"
                    shift
                    in_barclamp "$bc" branch_exists "$br" || \
                        die "$br is not a branch in barclamp $bc!"
                    [[ $br = *master ]] || \
                        die "Non-master branch for a barclamp passed.  Not valid for now."
                    barclamps["$bc"]="true"
                    is_in "$br" "${barclamp_branches["$bc"]}" || \
                        barclamp_branches["$bc"]+=" $br"
                done;;
            *) die "Unknown option $1 to $0 pull-requests-gen!";;
        esac
    done
    # The logic here is:
    # Find the "most central" branch for the current set of pull reqs.
    # Record that we need pull requests for each item we find.
    # lather, rinse, repeat until we are out of branches.

    for br in $(filter_branches_for_remote origin $(ordered_branches)); do
        # If we had to make barclamp-related modifications to our parent,
        # we will have to make them here as well.  Go ahead and save the
        # current ref for the branch and then merge changes from our parent.

        # Skip any branches that are not in the current release.
        branch_exists "$br" || continue
        local parent="$(parent_branch "$br")"
        if [[ $parent && ${refs[$parent]} ]]; then
            refs["$br"]="$(in_repo git rev-parse --verify -q "refs/heads/$br")"
            in_repo quiet_checkout "$br"
            in_repo git merge -q "$parent"
        fi
        for bc in $(barclamps_from_branch "$br"); do
            [[ ${barclamps[$bc]} ]] || continue
            for bcb in ${barclamp_branches["$bc"]}; do
                bc_pulls["$bc/$bcb"]="pull-req-$(in_barclamp "$bc" git_ref "$bcb")"
            done
            # If we get this far, we have barclamp references to update.
            if [[ ! ${refs["$br"]} ]]; then
                # We had not already saved a reference for this branch.
                # Make sure we save a refeence to the current branch if we have
                # not already, then check out the branch of interest and
                # save a ref to it.
                [[ $head ]] || head="$(in_repo git symbolic-ref HEAD)" || \
                    die "pull-requests-gen: Crowbar not on a branch!"
                if ! [[ $(in_repo git symbolic-ref HEAD) = "refs/heads/$br" ]]
                then
                    in_repo quiet_checkout "$br" || \
                    die "pull-requests-gen: Could not checkout $br"
                fi
                refs["$br"]="$(in_repo git rev-parse --verify -q "refs/heads/$br")"
            fi
            in_repo git add "barclamps/$bc"
        done
        if [[ ${refs["$br"]} ]]; then
            in_repo git commit -m "Add updated submodule references for $br"
            # ... and push it to our personal github repo.
            br_pulls["$br"]="pull-req-$(in_repo git_ref "$br")"
        fi
        if [[ ${branches["$br"]} && ! ${br_pulls["$br"]} ]]; then
            br_pulls["$br"]="pull-req-$(in_repo git_ref "$br")"
        fi
    done
    # OK, now we know how many pull requests we have to issue.
    prc=$((${#bc_pulls[@]} + ${#br_pulls[@]}))

    # issue the pull requests for our barclamps.
    for barclamp in "${!bc_pulls[@]}"; do
        local bc=${barclamp%%/*}
        local bc_base=${barclamp#*/}
        in_barclamp "$bc" git_push personal "$bc_base:${bc_pulls[$barclamp]}"
        local bc_head="$DEV_GITHUB_ID:${bc_pulls[$barclamp]}"
        if [[ $bc_base = feature/* ]]; then
            bc_base="$(best_parent_prefix)${bc_base##*/}" || exit 1
        fi
        local bc_name=$(in_barclamp $bc git config --get remote.origin.url)
        bc_name=${bc_name##*/}
        bc_name=${bc_name##*:}
        bc_name=${bc_name%.git}
        do_pull_request \
            "https://api.github.com/repos/dellcloudedge/$bc_name/pulls" \
            --title "$title [$n/$prc]" --base "$bc_base" --head "$bc_head" \
            --body "@$body" \
            --body "$(in_barclamp "$bc" diffstat_from_origin "$bc_base")"
        n=$(($n + 1))
    done

    # Now, issue the requests for branches.
    # Make sure they are ordered correctly.
    for br in $(filter_branches_for_remote origin $(ordered_branches)); do
        [[ ${br_pulls["$br"]} ]] || continue
        in_repo git_push personal "${br}:${br_pulls[$br]}"
        local br_head="$DEV_GITHUB_ID:${br_pulls[$br]}"
        if [[ $br = feature/* ]]; then
            br="$(best_parent_prefix)${br##*/}" || exit 1
        fi
        do_pull_request \
            "https://api.github.com/repos/dellcloudedge/crowbar/pulls" \
            --title "$title [$n/$prc]" --base "$br" --head "$br_head" \
            --body "@$body" --body "$(in_repo diffstat_from_origin "$br")"
        n=$(($n + 1))
        if [[ ${refs["$br"]} ]]; then
            in_repo quiet_checkout "$br"
            in_repo git reset --hard "${refs[$br]}"
        fi
    done
    [[ $head ]] && in_repo quiet_checkout "${head#refs/heads/}"
    rm -f "$body"
}

# Unconditionally push either the current branch or the branches
# passed on the command line to the personal remote.
push_branches() {
    # $@ = Local branches to push
    dev_is_setup
    local branches=("$@") br btp=()
    [[ $branches ]] || br=($(in_repo git symbolic-ref HEAD)) || \
        die "Main Crowbar repo is not on a branch we can push!"
    [[ $br ]] && branches=("${br#refs/heads/}")
    for br in "${branches[@]}"; do
        if in_repo git rev-parse --verify -q "$br" &>/dev/null; then
            btp+=("$br")
        else
            echo "$br is not a branch I can push!"
        fi
    done
    echo "Pushing ${btp[*]} to your Github fork of Crowbar."
    in_repo git_push personal "${btp[@]}"
}

# Show the releases that either the local repo or the origin repo knows about.
show_releases() {
    local sum ref r
    local br_re='^(refs/(heads|remotes/([^/]+))/)'
    local -A releases
    while read sum ref; do
        [[ $ref =~ $br_re ]] || continue
        ref=${ref#${BASH_REMATCH[1]}}
        # Filter out "extra" remotes.
        if [[ ${BASH_REMATCH[3]} ]]; then
            is_in "${BASH_REMATCH[3]}" "${!DEV_REMOTE_BRANCHES[*]} personal" || \
                continue
        fi
        case ${ref} in
            master) r=development;;
            stable/master) r=stable;;
            feature/*) r="${ref%/*}";;
            release/*)
                r="${ref#release/}"
                r=${r%%/*};;
        esac
        [[ ${releases["$r"]} ]] || releases["$r"]="$r"
    done < <(in_repo git show-ref master)
    echo "${releases[*]}"

}

# Given a release name, give us the proper brach prefix for it.
branch_prefix() {
    # $1 = release name
    case $1 in
        development) : ;;
        stable) echo "stable/";;
        feature/*) echo "$1/";;
        *) echo "release/$1/";;
    esac
}

# Given a branch, figure out what release it is in.
release_for_branch() {
    # $1 = branch to find out what release we are on
    local br=${1#refs/heads/}
    case $br in
        stable/*) echo "stable";;
        release/*) br=${br#release/}; echo "${br%%/*}";;
        feature/*) br=${br#feature/}; echo "feature/${br%%/*}";;
        *)
            if is_in "$br" "${!DEV_BRANCHES[*]}"; then
                echo "development"
            else
                die "Not on a release branch"
            fi;;
    esac
}

# Given a release, find the "best" parent release.  This will only
# be called if we don't already have metadata recorded for the
# parent relationship of this release.
find_best_parent() {
    # $1 = release to find the "best" parent of.
    #      If empty, use the release we are currently on.
    local br distance best_distance ref candidate merge_base release
    local best_candidates=()
    if [[ $1 ]]; then
        is_in "$1" "$(show_releases)" || \
            die "find_best_parents: $1 is not a release"
        release="$1"
    else
        release="$(release_for_branch $(in_repo git symbolic-ref HEAD))"
    fi
    [[ $release = development ]] && \
        die "By definition, the development release has no logical parent."

    if in_repo git_config_has "crowbar.releases.$1.parent"; then
        get_repo_cfg "crowbar.releases.$1.parent"
        return 0
    fi

    br="$(branch_prefix "$release")master"
    # Find the target that is the smallest number of commits away from us.
    # There may be more than one.  This algorithim is OK for a first pass,
    # but there are more complex and more accurate solutions out there.
    while read ref candidate; do
        candidate=${candidate#refs/heads/}
        [[ $candidate = $br ]] && continue
        distance="$(in_repo git rev-list --count --right-only "$candidate...$br")"
        [[ $best_distance ]] || best_distance=$distance
        if (( distance < best_distance )); then
            best_distance=$distance
            best_candidates=("$(release_for_branch "$candidate")")
        elif (( distance == best_distance )); then
            best_candidates+=("$(release_for_branch "$candidate")")
        fi
    done < <(git show-ref --heads master)
    local VERBOSE=1
    if (( ${#best_candidates[@]} == 0 )); then
        die "No best parent found for $release"
    elif (( ${#best_candidates[@]} == 1 )); then
        debug "It looks like $best_candidates is the parent of $release"
        candidate="$best_candidates"
    else
        debug "More than one good candidate for a parent found."
        debug "Please pick the one you want:"
        select candidate in "${best_candidates[@]}" "None of the above"; do
            case $candidate in
                'None of the above') die "Aborting.";;
                '') continue;;
                *) break;;
            esac
        done
    fi
    in_repo git config "crowbar.releases.$1.parent" "$candidate"
}

best_parent_prefix() {
    local res
    res="$(find_best_parent "$1")"
    echo "$(branch_prefix "$res")"
}

DEV_BRANCH_PREFIX="$(branch_prefix $(current_release))"

# Create a new release branch structure based on the current state of the
# Crowbar repositories.
cut_release() {
    local b remote old_prefix new_prefix
    local old_release new_release
    local -A barclamps branches

    [[ $1 ]] || die "cut_release: Please specify a name for the new release"

    # Test to see if release exists.
    is_in "$1" "$(show_releases)" && die "cut_release: Name already exists"

    old_release="$(current_release)"
    old_prefix="$(branch_prefix "$old_release")"
    new_prefix="$(branch_prefix $1)"
    crowbar_is_clean || \
        die "Crowbar repo must be clean before trying to cut a release!"

    # Sanoty-check that all the branches
    for b in $(branches_for_release); do
        branches["$b"]="${new_prefix}${b##*/}"
    done

    for b in $(barclamps_in_branch "${!branches[@]}"); do
        barclamps[$b]="master"
    done

    # Actaully create the new branches.
    for b in "${!branches[@]}"; do
        in_repo git branch -f --no-track "${branches[$b]}" "$b"
    done

    for b in "${!barclamps[@]}"; do
        in_barclamp "$b" git branch -f --no-track "${new_prefix}master" \
            "${old_prefix}master"
    done
    if git_managed_cache && ! branch_exists "${new_prefix}master"; then
        if in_cache branch_exists "${old_prefix}master"; then
            in_cache git branch "${new_prefix}master" "${old_prefix}master"
        else
            in_cache git branch "${new_prefix}master" master
        fi
    fi
    in_repo git config "crowbar.releases.$1.parent" "$old_release"
}

cut_feature() {
    [[ $1 ]] || die "Please give your new feature a name!"
    cut_release "feature/$1"
}

erase_release() {
    # $1 = release refix
    local b prefix parent parent_prefix
    [[ $1 = development ]] && die "Cannot erase the development release."
    is_in "$1" "$(show_releases)" || die "$1 is not a release we can erase!"
    prefix="$(branch_prefix "$1")"
    parent=$(find_best_parent "$1")
    parent_prefix=$(branch_prefix "$parent")
    if ! in_repo branches_synced '.' \
        "${parent_prefix}master" "${prefix}master"; then
        printf "$1 is not merged into $parent.  Really erase? (y/n): " >&2
        read -n 1
        [[ $REPLY != 'y' ]] && exit
    fi
    #    die "$1 is not merged into the development release, refusing to erase."
    for b in $(barclamps_in_branch "${!DEV_BRANCHES[@]}"); do
        in_barclamp "$b" branch_exists "${prefix}master" || continue
        in_barclamp "$b" git branch -D "${prefix}master"
    done
    for b in "${!DEV_BRANCHES[@]}"; do
        in_repo branch_exists "${prefix}$b" || continue
        in_repo git branch -D "${prefix}$b"
    done
}

# Check out the appropriate release branch for all the barclamps in a given
# release, and then check out the appropriate branch in the release.
switch_release() {
    local br bc current_branch new_base rel repo
    if [[ $1 ]]; then
        is_in "$1" "$(show_releases)" || die "switch: $1 does not exist"
        rel="$1"
    else
        rel="$(current_release)"
    fi
    crowbar_is_clean || \
        die "Crowbar repo must be clean before trying to switch releases!"

    new_base="$(branch_prefix "$rel")"

    current_branch=$(in_repo git symbolic-ref HEAD) || \
        die "switch: Crowbar not on a branch."
    current_branch=${current_branch##*/}
    # If the branches for this release have never been created locally,
    # do that now.
    if ! in_repo branch_exists "${new_base}master"; then
        for repo in "${!DEV_REMOTE_BRANCHES[@]}" personal; do
            for br in "${!DEV_BRANCHES[@]}"; do
                in_repo git rev-parse --verify -q \
                    "refs/remotes/$repo/${new_base}${br}" &>/dev/null || \
                    continue
                in_repo branch_exists "${new_base}${br}" && continue
                in_repo git branch --track "${new_base}${br}" \
                    "$repo/${new_base}${br}"
                for bc in $(barclamps_from_branch "${new_base}${br}"); do
                    in_barclamp "$bc" update_tracking_branches origin
                done
            done
        done
    fi
    in_repo branch_exists "${new_base}${current_branch}" || {
            echo "$rel does not have branch $current_branch, will checkout master instead."
        current_branch=master
    }
    in_repo quiet_checkout "${new_base}master"
    checkout "${current_branch}"
    if git_managed_cache && [[ $switch_include_cache ]]; then
        in_cache update_tracking_branches
        if in_cache branch_exists "${new_base}master"; then
            debug "Checking out ${new_base}master in the build cache, please be patient."
            in_cache quiet_checkout -f "${new_base}master"
        fi
    fi
    DEV_BRANCH_PREFIX="$new_base"
}

checkout() {
    local br new_base rel
    [[ $1 ]] || die "checkout: Please specify a branch"
    br=$1
    rel="$(current_release)"
    new_base=$(branch_prefix "$rel")
    in_repo branch_exists "${new_base}${br}" || \
        die "Branch $br does not exist in release $rel"
    in_repo git checkout "${new_base}${br}"
    switch_barclamps_to "${new_base}master"
}

build_crowbar() {
    local build_args=() b c target_os target_release exact
    local switch_include_cache=true
    target_release="$(current_release)"
    target_branch="$(in_repo git symbolic-ref HEAD)"
    target_branch="${target_branch##*/}"
    crowbar_is_clean || exit 1
    while [[ $1 ]]; do
        case $1 in
            --os) shift; target_os="$1";;
            --release) shift; target_release="$1";;
            --branch) shift; target_branch="$1";;
            --exact) exact=true;;
            *) build_args+=($1);;
        esac
        shift
    done
    [[ $target_os ]] || \
        die "Cannot build Crowbar, need to know what OS to stage it on!"
    update_all_tracking_branches
    build_args+=("--skip-lock")
    switch_release "${target_release:=$(current_release)}" || \
            die "Could not switch to $target_release for build!"
    [[ $target_branch ]] || die "Not on a branch, cannot continue!"
    checkout "$target_branch"
    if [[ $exact ]]; then
        in_repo git submodule update || \
            die "Could not check out submodule revisions for $target_release!"
    fi
    with_build_lock exec "$CROWBAR_DIR/build_crowbar.sh" \
        "$target_os" "${build_args[@]}"
}

reset_branch() {
    # $1 = branch to reset
    # $2 = target to reset it to.
    if [[ $(git symbolic-ref HEAD) = refs/heads/$1 ]]; then
        git reset --hard "$2"
    else
        git branch -f --no-track "$1" "$2"
    fi
}

reset_release() {
    crowbar_is_clean || exit 1
    local target_release target exclude_master prefix br remote
    local method bc skip_barclamps
    local -A branches barclamps barclamp_targets
    while [[ $1 ]]; do
        case $1 in
            --release) shift; target_release="$1";;
            --target) shift; target="$1";;
            --skip-master) exclude_master=true;;
            --skip-barclamps) skip_barclamps=true;;
            *) die "Unknown option $1 passed to reset-release";;
        esac
        shift
    done
    if [[ ! $target_release ]]; then
        exclude_master=true
        skip_barclamps=true
        target_release="$(current_release)"
    elif ! is_in "$target_release" "$(show_releases)"; then
        die "Release $target_release does not exist, cannot reset."
    fi
    if [[ ! $target ]]; then
        target=backup
    elif [[ ! $target =~ ^upstream|backup$ ]]; then
        die "Must reset to either upstream or backup!"
    fi
    prefix="$(branch_prefix "$target_release")"
    # Figure out what the proper target branches are going to be.
    for br in $(branches_for_release "$target_release"); do
        [[ $exclude_master && ${br##*/} = master ]] && continue
        remote="$(remote_for_branch "$br")"
        case $target in
            upstream) branches["$br"]="$remote/$br";;
            backup)
                case $(get_repo_cfg crowbar.backup.$remote.method) in
                    prefix)
                        branches["$br"]=$(get_repo_cfg "crowbar.backup.$remote.remote")
                        branches["$br"]+="/$(get_repo_cfg "crowbar.backup.$remote.prefix")"
                        branches["$br"]+="/$br";;
                    remote)
                        branches["$br"]=$(get_repo_cfg "crowbar.backup.$remote.remote")
                        branches["$br"]+="/$br";;
                    *) die "Unknown backup method for $br in Crowbar";;
                esac;;
            *) die "Don't know how to reset to $target_method";;
        esac
        if ! in_repo git rev-parse --quiet --verify \
            "${branches[$br]}" &>/dev/null; then
            if [[ $target = backup ]]; then
                debug "$br has never been backed up, skipping."
                unset branches[$br]
            elif [[ $target = upstream ]]; then
                die "Cannot reset $br to ${branches[$br]}"
            fi
        fi
        [[ $skip_barclamps = true ]] && continue
        for bc in $(barclamps_from_branch "$br"); do
            [[ ${barclamps[$bc]} ]] && continue
            in_barclamp "$bc" branch_exists "${prefix}master" || continue
            barclamps[$bc]="${prefix}master"
            case $target in
                upstream) barclamp_targets[$bc]="origin/${prefix}master";;
                backup)
                    case $(get_barclamp_cfg "$bc" crowbar.backup.origin.method) in
                        prefix)
                            barclamp_targets[$bc]="origin/$(get_barclamp_cfg "$bc" crowbar.backup.origin.prefix)"
                            barclamp_targets[$bc]+="/${prefix}master";;
                        remote)
                            barclamp_targets[$bc]="$(get_barclamp_cfg "$bc" crowbar.backup.origin.remote)/${prefix}master";;
                        *) die "Unknown backup method for barclamp $bc!";;
                    esac;;
                *) die "Don't know how to reset barclamp $bc to $target_method";;
            esac
            if ! in_barclamp "$bc" git rev-parse --quiet --verify \
                "${barclamp_targets[$bc]}" &>/dev/null; then
                if [[ $target = backup ]]; then
                    debug "${barclamps[$bc]} in $bc has never been backed up, skipping."
                    unset barclamps[$bc]
                elif [[ $target = upstream ]]; then
                    debug "Cannot reset barclamp $bc to ${barclamp_targets[$bc]}"
                    unset barclamps[$bc]
                fi
            fi
        done
    done
    for bc in "${!barclamps[@]}"; do
        in_barclamp "$bc" branch_exists "${barclamps[$bc]}" || continue
        in_barclamp "$bc" \
            reset_branch "${barclamps[$bc]}" "${barclamp_targets[$bc]}"
    done
    for br in "${!branches[@]}"; do
        in_repo reset_branch "$br" "${branches[$br]}"
    done
}

case $1 in
    is_clean) shift; crowbar_is_clean "$@";;
    fetch) shift; fetch_all "$@";;
    sync) shift; sync_everything "$@";;
    setup) setup;;
    backup) shift; backup_everything "$@";;
    push) shift; push_branches "$@";;
    pull-requests-prep) pull_requests_prep;;
    pull-requests-gen) shift; pull_requests_gen "$@";;
    help) dev_help;;
    release) current_release;;
    releases) show_releases;;
    cut_release) shift; cut_release "$@";;
    new-feature) shift; cut_feature "$1";;
    switch) shift; switch_release "$@";;
    branches) shift; branches_for_release "$@";;
    checkout) shift; checkout "$@";;
    build) shift; build_crowbar "$@";;
    show-repos) show_github_repos;;
    remote) shift; remote_wrapper "$@";;
    erase-feature) shift; erase_release "feature/$1";;
    find-parent) shift; find_best_parent "$@";;
    reset-release) shift; reset_release "$@";;
    scrub-merged-pulls) shift; scrub_merged_pulls "$@";;
    create-barclamp) shift
        [[ -d $CROWBAR_DIR/barclamps/$1 ]] || \
            die "Barclamp $1 already exists"
        "$CROWBAR_DIR/extra/barclamp_create.rb" "$@" || exit 1
        (   cd "$CROWBAR_DIR/barclamps/$1"
            git init .
            git add .
            git commit -m "Initial commit"
        );;
    *) dev_short_help; exit 1;;
esac