SAM-local fails to start API with multiple stacks

Question

I want to add resources to my root stack and somehow found a function where I can first get stack first like this

   my_api = RestApi.from_rest_api_attributes(self, "RestApi",
                                               rest_api_id='test',
                                               root_resource_id='test'
                                

           )

reference https://docs.aws.amazon.com/cdk/api/v1/python/aws_cdk.aws_apigateway/README.html#breaking-up-methods-and-resources-across-stacks

and then trying to add resources after getting this stack

mine_ = my_api.root.add_resource("mine")
mine_.add_method(
            http_method='GET',
            authorizer=api_authorizer
        )

on this I am getting this error

ValueError: urls must start with a leading slash

any help would be highly appreciated ..

Edit full traceback of error:

Traceback (most recent call last):
  File "samcli/__main__.py", line 12, in <module>
  File "click/core.py", line 829, in __call__
  File "click/core.py", line 782, in main
  File "click/core.py", line 1259, in invoke
  File "click/core.py", line 1259, in invoke
  File "click/core.py", line 1066, in invoke
  File "click/core.py", line 610, in invoke
  File "samcli/lib/iac/utils/helpers.py", line 55, in wrapper
  File "samcli/commands/_utils/iac_validations.py", line 79, in wrapped
  File "click/decorators.py", line 73, in new_func
  File "click/core.py", line 610, in invoke
  File "samcli/lib/telemetry/metric.py", line 174, in wrapped
  File "samcli/lib/telemetry/metric.py", line 141, in wrapped
  File "samcli/lib/utils/version_checker.py", line 42, in wrapped
  File "samcli/cli/main.py", line 90, in wrapper
  File "samcli/commands/local/start_api/cli.py", line 128, in cli
  File "samcli/commands/local/start_api/cli.py", line 205, in do_cli
  File "samcli/commands/local/lib/local_api_service.py", line 68, in start
  File "samcli/local/apigw/local_apigw_service.py", line 173, in create
  File "flask/app.py", line 98, in wrapper_func
  File "flask/app.py", line 1275, in add_url_rule
  File "werkzeug/routing.py", line 666, in __init__
ValueError: urls must start with a leading slash
[8038] Failed to execute script __main__

Answer 1

urls must start with a leading slash is not an error that CDK throws. It's a werkzeug error, you can see the code in question here.

So the error doesn't have anything to do with your CDK code.

The reason for the error is that SAM does not support testing multiple stacks at this point. So either compile everything into a single stack, or avoid using sam-beta-cdk.