Adding CustomType to a ListAttribute changes generated description to List of Dynamic

[ewbankkit]

Terraform CLI and terraform-plugin-docs Versions

% tfplugindocs -v
tfplugindocs Version dev

In go.mod: github.com/hashicorp/terraform-plugin-docs v0.18.0

Provider Code

"health_check_arns": schema.ListAttribute{ /*START ATTRIBUTE*/
                        ElementType: types.StringType,
                        CustomType:  cctypes.MultisetType,
                        Description: "The Amazon Resource Names (ARNs) of the health check to associate with the protection.",
                        Optional:    true,
                        Computed:    true,
                        Validators: []validator.List{ /*START VALIDATORS*/
                                listvalidator.SizeAtMost(1),
                                listvalidator.ValueStringsAre(
                                        stringvalidator.LengthBetween(1, 2048),
                                ),
                        }, /*END VALIDATORS*/
                        PlanModifiers: []planmodifier.List{ /*START PLAN MODIFIERS*/
                                listplanmodifier.UseStateForUnknown(),
                        }, /*END PLAN MODIFIERS*/
                }, /*END ATTRIBUTE*/

Expected Behavior

Generate:

health_check_arns (List of String) The Amazon Resource Names (ARNs) of the health check to associate with the protection.

Actual Behavior

Generated:

health_check_arns (List of Dynamic) The Amazon Resource Names (ARNs) of the health check to associate with the protection.

Steps to Reproduce

1. tfplugindocs generate --flags

How much impact is this issue causing?

Medium

Additional Information

Relates hashicorp/terraform-provider-awscc#1463.

Code of Conduct

• I agree to follow this project's Code of Conduct

[bflad]

Drive-by note: The framework website documentation does not go into too many of the details about creating a custom collection type, but in that situation, the custom type "owns" the entire type definition (e.g. the attribute ElementType is not effective). You can see some of that implementation at play here:

https://github.com/hashicorp/terraform-plugin-framework/blob/4ca111592bfec2bec39662261ad147002bc56c34/resource/schema/list_attribute.go#L199-L208

Maybe the framework could/should raise an attribute implementation error when it detects both CustomType and ElementType being set.

In your situation it might be a matter of doing something like (removing the exported MultisetType variable and instead exporting the type directly):

CustomType:  cctypes.MultisetType{basetypes.ListType{ElementType: basetypes.StringType}},

That should cause the GetProviderSchema RPC to return the "full" type information for the attribute, which is what terraform-plugin-docs eventually uses.

[bflad]

For what its worth about:

Maybe the framework could/should raise an attribute implementation error when it detects both CustomType and ElementType being set.

Could also be turned around as a framework feature request that attributes could automatically do what you tried to do there with both fields. There is the attr.TypeWithElementType interface already available that could potentially help in this situation if the CustomType implemented it and the framework attribute GetType() logic checked for it. While it would likely solve this exact situation, I'm not sure off the top of my head whether just adjusting that GetType() logic would fully enable correct type handling everywhere else in the framework though. We would need to verify. 😄

[ewbankkit]

@bflad Thanks for the explanation.
I'll close this Issue once I've verified the solution.

[ewbankkit]

+1 to

Maybe the framework could/should raise an attribute implementation error when it detects both CustomType and ElementType being set.

I'll add an Issue in https://github.com/hashicorp/terraform-plugin-framework.

[ewbankkit]

Yes, removing the ElementType (and reworking MultisetType) works. Thanks.

[github-actions]

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