Support @resourceIdentifier tag in HttpLabelTraitValidator

[MintuJ]

cross posting from an internal chat

Hi team,

We are encountering an API Gateway deployment error with our Smithy model:

A sibling ({clusterIdentifier}) of this resource already has a 
variable path part -- only one is allowed

Issue: Our Smithy model has inconsistent path parameter names:

• Existing operations: /cluster/{identifier}/policy
• Newly added operations: /cluster/{clusterIdentifier}/stream

We want to maintain clusterIdentifier in our Stream operations for semantic clarity, but Smithy's @httpLabel trait requires input field names to exactly match URI path parameters. This means we can't use:

@http(uri: "/cluster/{identifier}/stream")
input {
    @httpLabel
    @resourceIdentifier("identifier")
    clusterIdentifier: ClusterId  // Incorrect
}

Is there a Smithy pattern or workaround that allows us to to be flexible with field names (clusterIdentifier) while satisfying API Gateway's path parameter consistency requirement?

Thanks in advance!

---

Models:

Parent Resource:

@arn(template: "cluster/{identifier}")
resource Cluster {
    identifiers: {
        identifier: ClusterId
    }
    properties: {
      // properties
    }
    read: GetCluster
    // operations
    resources: [
        Stream
    ]
}


@readonly
@http(code: 200, method: "GET", uri: "/cluster/{identifier}")
operation GetCluster {
    input := for Cluster {
        @required
        @httpLabel
        $identifier
    }
    output := with [ClusterOutputMixin] {
     // ...
   }
}

Child Resource:

@arn(template: "cluster/{identifier}/stream/{streamIdentifier}")
resource Stream {
    identifiers: {
        identifier: ClusterId
        streamIdentifier: StreamId
    }
    properties: {
     // properties
    }
    read: GetStream
}

@readonly
@http(code: 200, method: "GET", uri: "/cluster/{identifier}/stream/{streamIdentifier}")
operation GetStream {
    input := for Stream {
        @httpLabel
        @required
        @resourceIdentifier("identifier")
        clusterIdentifier: ClusterId

        @httpLabel
        @required
        $streamIdentifier
    }
    output := with [StreamOutputMixin] {
        // ...
    }
}

[MintuJ]

Relevant code line: https://github.com/smithy-lang/smithy/blob/main/smithy-model/src/main/java/software/amazon/smithy/model/validation/validators/HttpLabelTraitValidator.java#L79

Some options:

1. HttpLabelTraitValidator looks up resourceIdentifier too
2. @httpLabel supports a parameter where a custom label name can be defined