# A module for working with dgit(1) repositories
#
# Copyright (C) 2017, 2020 Sean Whitton
#
# Maintainer: Sean Whitton <spwhitton@spwhitton.name>

# DEFINITION
#
# A dgit repository is a git repository containing special remote refs
# of the form `remotes/dgit/dgit/*` and possibly also branches of the
# form `dgit/*`.  See dgit(7) for more details.
#
# USAGE
#
# To make mr use this file, add a line like this inside the [DEFAULT]
# section of your ~/.mrconfig:
#
#   include = cat /usr/share/mr/dgit
#
# With this module active,
#
# `mr update` will:
#
# (1) if the current branch is named `dgit/SUITE`, call `dgit pull`.
#
# (2) use `dgit fetch` to update all remotes/dgit/dgit/*` refs.
#
# `mr register` will add a post_checkout hook that calls `dgit fetch`.
#
# DESIGN
#
# A dgit repository may have been obtained with `dgit clone`, or `git
# clone` followed by `dgit fetch`.  It is not possible for us to
# determine which of these methods was used after the fact.
#
# For this reason, we do not define dgit_register and dgit_test so as
# to generate .mrconfig lines like
#
#   [foo]
#   checkout = dgit clone foo
#
# because that would fail to fetch branches not published to
# dgit-repos, such as branches published to alioth.debian.org.
#
# Instead, we extend git_update and git_register to obtain updates
# from dgit-repos.

# we obtain the source package name from git and pass it to dgit with
# the latter's -p option, because the currently checked out branch may
# not contain debian/control, which would cause dgit fetch without -p
# to fail
lib =
    set_source () {
        if [ -z "$source" ]; then
            source=$(git cat-file blob dgit/dgit/$1:debian/control \
                         | awk -F': ' '$1 ~ /Source/ { print $2 }')
        fi
    }

# We can't use git_update_append because mr's built-in default `git
# pull` will often fail on a `dgit/SUITE` branch.  After a `dgit
# clone`, (i) `dgit/SUITE` has no upstream tracking branch, and (ii)
# the 'origin' remote might not exist on the remote end (it depends on
# whether the package has ever been uploaded with `dgit push`)
git_update =
    current_branch="$(git rev-parse --abbrev-ref HEAD)"
    if [ "$(echo $current_branch | cut -s -d/ -f1)" = "dgit" ]; then
        # (1) above
        dgit pull
    else
        # mr's built-in git_update
        git pull "$@"
    fi
    # (2) above
    for suite in $(git show-ref | grep refs/remotes/dgit/dgit | cut -d/ -f5 ); do
        # skip if we just called `dgit pull` on this suite
        if ! [ "$current_branch" = "dgit/$suite" ]; then
            set_source $suite
            dgit -p$source fetch $suite
        fi
    done

git_register_append =
    lines="cd '$MR_REPO'"
    for suite in $(git show-ref | grep refs/remotes/dgit/dgit | cut -d/ -f5 ); do
        set_source $suite
        echo "Registering dgit suite: $suite in $MR_CONFIG"
        lines="$lines; dgit -p$source fetch $suite"
    done
    if ! [ "$lines" = "cd '$MR_REPO'" ]; then
        mr -c "$MR_CONFIG" config "`pwd`" post_checkout="$lines"
    fi