Resource model break when specifying an array with unique: true

[rene84]

I've noticed when specifying an array with unique: true translates the model into a Set instead of an Array (makes sense)

but then when passing an actual array as example input, the resource provider fails. Consider for example:

        "Tags": {
            "type": "array",
            "maxItems": 50,
            "uniqueItems": true,
            "insertionOrder": false,
            "description": "An array of key-value pairs to apply to this resource.",
            "items": {
                "$ref": "#/definitions/Tag"
            }
        },

with input:

"Tags": [{
            "Key": "name",
            "Value": "value"
        }]

gives error

"message": "Error: Error: Unsupported type: object [Tag] for tags (Error)",

Removing the uniqueItems fixes the issue and the main thing I notice is that in the generated code the type changes from a Set to an Array

[eduardomourar]

I think this is related to some issues in the class-transformer library. Maybe those workarounds are relevant: https://github.com/typestack/class-transformer/issues/288#issuecomment-614754298 and https://github.com/typestack/class-transformer/issues/495#issuecomment-756449822.

Could you post an snippet of your models.ts file? I believe you can modify your generated models.ts with the provided workaround in order to figure out which change has to be made to the TypeScript code generator.

[rene84]

Sure. It looks like this:

    @Expose({ name: 'Tags' })
    @Transform(
        (value: any, obj: any) =>
            transformValue(Tag, 'tags', value, obj, [Set]),
        {
            toClassOnly: true,
        }
    )
    tags?: Optional<Set<Tag>>;

With uniqueItems: false it looks like this

    @Expose({ name: 'Tags' })
    @Type(() => Tag)
    tags?: Optional<Array<Tag>>;

[eduardomourar]

You can find a test reproducing what you faced here.

[eduardomourar]

This has been fixed by https://github.com/aws-cloudformation/cloudformation-cli-typescript-plugin/pull/98.