function: Add validation to prevent collection parameters/return definitions from having missing element types

[austinvalle]

Module version

v1.6.0

Use-cases

#931 will introduce a new internal interface fwfunction.ParameterWithValidateImplementation and fwfunction.ReturnWithValidateImplementation that will enable us to implement logic for validating function parameter and return definitions.

We should introduce validation on all collection parameter and return definitions to ensure that element types are populated.

resp.Definition = function.Definition{
    Parameters: []function.Parameter{
        function.ListParameter{
            Name: "list",
            // Missing element type!
        },
    },
    Return: function.ListReturn{
        // Missing element type!
    },
}

Proposal

Implementation could look similar to collection attributes, such as ListAttribute:

terraform-plugin-framework/datasource/schema/list_attribute.go

Lines 210 to 212 in f86c88c

	if a.CustomType == nil && a.ElementType == nil {
	resp.Diagnostics.Append(fwschema.AttributeMissingElementTypeDiag(req.Path))
	}

We should add this to:

• ListParameter
• ListReturn
• MapParameter
• MapReturn
• SetParameter
• SetReturn

References

• all: Add dynamic type, attribute, and function support  #931