Autorest(modelerfour) doesn't handle circular dependencies in additionalProperties

[johanste]

I have a self-referential recursive model definition. Autorest doesn't seem to like it.

$> autorest --input-file=any.json --python      

WARNING: AutoRest has not been tested with Node versions greater than v14.

AutoRest code generation utility [cli version: 3.0.6335; node: v15.4.0, max-memory: 4096 MB]
(C) 2018 Microsoft Corporation.
https://aka.ms/autorest
NOTE: AutoRest core version selected from configuration: ~3.0.6298.
   Loading AutoRest core      '/Users/johanstenberg/.autorest/@autorest_core@3.0.6369/node_modules/@autorest/core/dist' (3.0.6369)
   Loading AutoRest extension '@autorest/python' (latest->5.6.1)
   Loading AutoRest extension '@autorest/modelerfour' (4.15.442->4.15.442)

...

WARNING (PreCheck/CheckDuplicateSchemas): Checking for duplicate schemas, this could take a (long) while.  Run with --verbose for more detail.
FATAL: Error: RECURSING!  Saw schema Any more than once.
  Error: Plugin modelerfour reported failure.

See below for an example swagger that illustrates the issue...

{
  "swagger": "2.0",
  "info": {
    "title": "Recursive",
    "version": "1.0"
  },
  "produces": [ "application/json" ],
  "consumes": [ "application/json" ],
  "paths": {
    "/resources/{resourceId}": {
      "parameters": [
        {
          "name": "resourceId",
          "in": "path",
          "type": "string",
          "required": true
        }
      ],
      "put": {
        "operationId": "createResource",
        "parameters": [
          {
            "name": "body",
            "in": "body",
            "schema": {
              "$ref": "#/definitions/Resource"
            }
          }
          ],
        "responses": {
          "200": {
            "description": "Success, ja!",
            "schema": {
              "$ref": "#/definitions/Resource"
            }
          }
        }
      }
    }
  },
  "definitions": {
    "Any": {
      "additionalProperties": {
        "$ref": "#/definitions/Any"
      }
    },
    "Resource": {
      "type": "object",
      "properties": {
        "name": {
          "type": "string"
        },
        "randomProperties": {
          "$ref": "#/definitions/Any"
        }
      }
    } 
  }
}

[timotheeguerin]

Hey @johanste could you confirm the PR fixes the issue for you. There is instruction here to test it locally
#3819 (comment)