[BUG] Machine Learning Batch Endpoint API Spec documents unsupported identity types

[promisinganuj]

API Spec link

https://github.com/Azure/azure-rest-api-specs/blob/main/specification/machinelearningservices/resource-manager/Microsoft.MachineLearningServices/stable/2025-09-01/mfe.json#L13050-L13052

API Spec version

2025-06-01, 2025-09-01

Describe the bug

According to the API spec the API supports system assigned and/or user assigned identities. But passing a user assigned identity results in the following error:

Error when passing "SystemAssigned,UserAssigned":

{
  "error": {
    "code": "CannotSetResourceIdentity",
    "message": "Resource type 'Microsoft.MachineLearningServices/workspaces/batchEndpoints' does not support creation of 'SystemAssigned, UserAssigned' resource identity. The supported types are 'SystemAssigned'."
  }
}

Error when passing "UserAssigned":

{
  "error": {
    "code":" CannotSetResourceIdentity",
    "message": "Resource type 'Microsoft.MachineLearningServices/workspaces/batchEndpoints' does not support creation of 'UserAssigned' resource identity. The supported types are 'SystemAssigned'."
  }
}

This is causing issues downstream in an SDK generated from this API spec.

Expected behavior

As batch endpoint only support SystemAssigned identity, the identity block should reference the right identity definition. Currently, it refers to:

      "properties": {
        "identity": {
          "description": "Managed service identity (system assigned and/or user assigned identities)",
          "$ref": "../../../../../common-types/resource-management/v3/managedidentity.json#/definitions/ManagedServiceIdentity"
        }

Instead, it should be referring it.

"$ref": "../../../../../common-types/resource-management/v3/types.json#/definitions/Identity"

And the description should be updated accordingly.

Actual behavior

Error as described above

Reproduction Steps

PUT https://management.azure.com/subscriptions/{subscriptionID}/resourceGroups/{resourceGroupName}/providers/Microsoft.MachineLearningServices/workspaces/{machineLearningWorkspaceName}/batchEndpoints/{batchEndpointName}?api-version=2025-09-01

{
    "identity": {
        "type": "SystemAssigned,UserAssigned",
        "userAssignedIdentities": {
            "identityId": {}
        }
    },
    "location": "australiaeast",
    "properties": {
        "authMode": "AADToken",
        "description": "Test batch endpoint"
    },
    "tags": {
        "Environment": "Test"
    }
}

Environment

No response