Fix image acquisition when CI is run outside of a pull request (#1280)

set -uex

if [[ $# -ne 1 ]]; then

    echo "Usage: ci-output-build-image <base revision commit hash>"

    exit 1

if [[ $# -eq 1 ]]; then

    # If a base revision is given as an argument, use it

    BASE_REVISION="$1"

else

    # Otherwise, for the use-case where CI is being run directly on the main branch

    # without a pull request, use the commit hash of HEAD

    BASE_REVISION="$(git rev-parse HEAD)"

fi

BASE_REVISION="$1"

SCRIPT_PATH="$(realpath "$(dirname "$0")")"

"${SCRIPT_PATH}/acquire-base-image" --nothing-or-local-if-changed "${BASE_REVISION}"