Validator for duplicate names in iamResource trait

[tkyadav]

Background

IamResourceTraitValidator does not validates conflicting resource names in IAM space. For example, assume there exists two resource shapes Resource1 and Resource2. If I add trait @iamResource(name: "Resource1") on Resource2, there are conflicting resource names in the IAM space. This behavior is not detected/prevented by any validator in smithy.

Testing

Wrote a unit test for the validator.

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[0xjjoyy]

I think you can use expectTrait. As hasTrait is already called, if the trait isn't actually resolved then that's an error - https://smithy.io/javadoc/1.5.1/software/amazon/smithy/model/shapes/Shape.html#expectTrait(java.lang.Class)

[0xjjoyy]

I think can use expectTrait - https://smithy.io/javadoc/1.5.1/software/amazon/smithy/model/shapes/Shape.html#expectTrait(java.lang.Class)

[syall]

Instead of creating an event per conflict found, I think it would be better to collect all conflicting resources and then emit 1 event.

For example, if there were 3 resources that conflict:

// Omitted other irrelevant shapes
@aws.iam#iamResource(name: "Beer")
resource BadIamResourceName1 {}
@aws.iam#iamResource(name: "Beer")
resource BadIamResourceName2 {}
@aws.iam#iamResource(name: "Beer")
resource BadIamResourceName3 {}

the validator currently would emit 2 events:

[ERROR] smithy.example#BadIamResourceName2: Conflicting IAM resource names in an entire service closure is not allowed. This IAM resource name `Beer` conflicts with other resource `(resource: `smithy.example#BadIamResourceName1`)` in the service `smithy.example#MyService`. | IamResourceTraitConflictingName
[ERROR] smithy.example#BadIamResourceName3: Conflicting IAM resource names in an entire service closure is not allowed. This IAM resource name `Beer` conflicts with other resource `(resource: `smithy.example#BadIamResourceName1`)` in the service `smithy.example#MyService`. | IamResourceTraitConflictingName

Also, this will create events based on the order the model is traversed, which may not be stable across model changes.

Instead, I think it would be better to collect all of the conflicting names into 1 event:

[ERROR] smithy.example#MyService: Multiple IAM resources defined with the same IAM resource name is not allowed in a service closure, but found multiple resources named `Beer` in the service `smithy.example#MyService`: `smithy.example#BadIamResourceName1`, `smithy.example#BadIamResourceName2`, `smithy.example#BadIamResourceName3` | IamResourceTraitConflictingName

Also, should resources without the iamResource trait be included in this validation?

[syall]

I think the method you want to use is IamResourceTrait::resolveResourceName().

To get the resource name in the IAM space, something like this could work:

String resourceName = IamResourceTrait.resolveResourceName(resource);

[kstich]

Note that this means the .getName check in the if must also be removed, as resolveResourceName checks other sources.