The operation does not carry the decorator defined for its namespace/interface when it is reference to other interface

[chunyu3]

Hi all

When we defined operation one in main.cadl, and reference in client.cadl as following:
main.cadl

namespace Azure.ClientAndOperationGroupService;

@autoRoute
namespace Alpha {​​
    #suppress "@azure-tools/cadl-azure-core/use-standard-operations" "This is test code."
    @action
    op one(): string;
}​​

client.cadl

@client({​​
  name: "NewOperationGroupService",
  service: Azure.ClientAndOperationGroupService
}​​)
interface NewOperationGroupService{​​
    oneFun is Azure.ClientAndOperationGroupService.Alpha.one;
}​​

The @autoRoute decorator will not pass-down to the operation oneFun. Is it the expected behavior? 

[timotheeguerin]

This is by design(#1335) and is the same issue as #1420

What we don't have and we could maybe need is a op myRename use externalOp where it wouldn't be a copy but a reference to the operation so we'd look there for the information.

[markcowl]

Consolidating the issues here

• What is needed is a mechanism for reusing an operation, including its decoration
• This is likely mitigated by use of the azure.core operation templates, which should explicitly define autoRoute and operation path on the operations. Not sure that we should define a mechanism to make it easy to reshape APIs that do not use azure.core, or similar patterns that promote operation portability.
• Should be able to handle
  • reusing operations using @AutoRoute - this may simply be that operations must use azure core operation templates
  • avoid redefining operation path with operation rename, again, use of azure core templates in the originals spec should fix this.
  • We should be able to carry over additional operation decoration from the spec, this is where the client definition might have to duplicate things if a spec is not written with reusing operations in mind