While a lambda is still processing (archive unpacking etc), the lambda state should be set to "Pending" (currently "Active") and invocations to that lambda should fail (currently, it can end up in a inconsistent state in this case, like lambdas being executed without layers).

Lambda state should reflect the current internal state, and invocations should fail if not active.
def publish_version(function):
    region = LambdaRegion.get()
    arn = func_arn(function)
    if arn not in region.lambdas:
        return not_found_error(arn)
    return jsonify(publish_new_function_version(arn))
@app.route("%s/functions/<function>/versions" % API_PATH_ROOT, methods=["GET"])
def list_versions(function):
    region = LambdaRegion.get()
    arn = func_arn(function)
    if arn not in region.lambdas:
        return not_found_error(arn)
    return jsonify({"Versions": do_list_versions(arn)})
@app.route("%s/functions/<function>/aliases" % API_PATH_ROOT, methods=["POST"])
def create_alias(function):
    region = LambdaRegion.get()
    arn = func_arn(function)
    if arn not in region.lambdas:
        return not_found_error(arn)
    data = json.loads(request.data)
    alias = data.get("Name")
    if alias in region.lambdas.get(arn).aliases:
        return error_response(
            "Alias already exists: %s" % arn + ":" + alias,
            404,
            error_type="ResourceConflictException",
        )
    version = data.get("FunctionVersion")
    description = data.get("Description")
    return jsonify(do_update_alias(arn, alias, version, description))