[Question] How to define `$ref` to definitions in other files when overwriting definition

[archerzz]

Before asking the question:

• [x] have you checked the faq, the documentation in the docs folder and couldn't find the information there
• [x] have you checked existing issues for a similar question?

Problem

I have a definition which has excessive properties. So I want to re-write it as follow, using where-model directives.

 - where-model: DdosProtectionPlan
    transform: >
      return {
        "description": "A DDoS protection plan in a resource group.",
        "x-ms-azure-resource": true,
        "properties": {
          "properties": {
            "x-ms-client-flatten": true,
            "$ref": "#/definitions/DdosProtectionPlanPropertiesFormat",
            "description": "Properties of the DDoS protection plan."
          },
          "etag": {
            "readOnly": true,
            "type": "string",
            "description": "A unique read-only string that changes whenever the resource is updated."
          }
        },
        "allOf": [
            {
              "$ref": "./network.json#/definitions/Resource" ## PROBLEM!
            }
        ]
      }

The problem is that when using autorest to generate the codes, I got the following error. [Note]: If I modify the original swagger JSON file, the generation is OK.

Error: $ref to original location './network.json#/components/schemas/Resource' is not found in the new refs collection

I tried many alternatives, and it seems that when where-model directive is being processed, the reference key is changed to a global absolute value. If I changed the $ref to file:///C:/Users/mingzhehuang/workspaces/azure/azure-rest-api-specs/specification/network/resource-manager/Microsoft.Network/stable/2021-02-01/network.json#/definitions/Resource, the generation is fine.

Question

Is there a way I can safely refer to definitions in other files when overwriting the definition? Thanks.

[timotheeguerin]

Yeah, I think this is due to how references are expanded at the beginning but not again later. you can use $documentPath to make the full reference

"$ref": "$documentPath/../network.json#/definitions/Resource"

We could maybe do another crawl of the reference after the transform step

[archerzz]

Thanks @timotheeguerin !

It would be better to re-calculate the $ref if the given value is not found. That will make the customization much easier.

[archerzz]

@timotheeguerin Do you want me close this issue, or keep it open as a feature request?

[timotheeguerin]

We can keep this issue for it. I tried adding the crawling of reference after. The current issue is that when it crawl reference it might also add new files if this is a reference to another file that wasn't referenced before. Then it would need to make sure it loads it and we need to decide what we do with it. Do we rerun the previous stages on it(transforms) or we just act like it is already good and keep going.