CfnMapping.find_in_map: Template Validation Error When Optional default_value is not specified.

[drobbins-ancile]

Describe the bug

The following code synthesizes successfully but produces a template error in the CloudFormation console:

ipset_mapping = CfnMapping(
    self,
    "IpSetMapping",
    lazy=True,
    mapping={
        "us-east-1": {
            "Prod": "arn:aws:wafv2:12345",
        }
	}
)


ipset_mapping.find_in_map(
  Fn.sub("${AWS::Region}"),
  environment.value_as_string
)

According to the docs the default_value parameter is optional.

If the default_value parameter is specified the synthesized template deploys successfully.

Expected Behavior

The synthesized cloudformation template can be deployed without error.

Current Behavior

An error message is displayed in the CloudFormation console:

Template error: every Fn::FindInMap object requires three parameters, the map name, map key and the attribute for return value.

Reproduction Steps

1. Create a mapping and reference a value in the mapping using the find_in_map method without specifying the default_value parameter.
2. Attempt to deploy the synthesized template

Possible Solution

Either account for the cloudformation API requirement by making the default_value parameter required or fix the API to support this parameter being optional.

Additional Information/Context

No response

CDK CLI Version

2.106.1 (build a2e5f65)

Framework Version

No response

Node.js Version

v21.1.0

OS

Mac

Language

Python

Language Version

3.12.0

Other information

No response

[pahud]

I didn't get it.

Are you able to deploy this sample and see the output as below?

[github-actions]

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