"git submodule update --init --recursive" with second change for submodules referencing unpushed code (alternative URIs for submodules)

submodule_update_alturl.sh

#!/bin/sh

unset CDPATH


cd_to_toplevel () {
    cdup=$(git rev-parse --show-toplevel) &&
    cd "$cdup" || {
        echo >&2 "Cannot chdir to $cdup, the toplevel of the working tree"
        exit 1
    }
}

cd_to_toplevel

set -e
#set -x


list_all_submodule_names() {
    git config --list --name-only | \
        grep '^submodule\.' | \
        rev | cut -d. -f 2- | rev | \
        cut -d. -f 2- | \
        sort | uniq
}

handle_submodules_in_current_directory() {

    git submodule init

    IFS='
'
    for MODULE_NAME in $(list_all_submodule_names); do
        local SP=$(git config --get submodule."$MODULE_NAME".path || true)
        if [ -z "$SP" ]; then SP="$MODULE_NAME"; fi

        # First time trying without hacks
        if git submodule update "$@" -- "$SP" ; then
            # OK, no need for tricks
            :;
        else
            local ADDITIONAL_URL_NAME=ALTURL_${MODULE_NAME}
            local ADDITIONAL_URL=$(eval "echo \"\$$ADDITIONAL_URL_NAME\"")
            if [ -n "$ADDITIONAL_URL" ]; then
                echo Trying alternative URL $ADDITIONAL_URL
                git -C "$SP" fetch "$ADDITIONAL_URL" '+refs/heads/*:refs/remotes/alturl/*' '+refs/tags/*:refs/tags/alturl/*'
            else
                echo "No alternative URL for $MODULE_NAME"
                echo "Use $ADDITIONAL_URL_NAME environment variable to give it a second chance"
                exit 1
            fi
            # Now retry
            git submodule update "$@" -- "$SP"
        fi

        (
            echo Entering "$SP"
            cd "$SP"
            handle_submodules_in_current_directory
            echo Leaving "$SP"
        )
    done
}

handle_submodules_in_current_directory