Problem statement

swagger flatten --with-flatten=remove-unused does not remove models that were only referenced by models that were just removed.

That is, if I have model Book which uses model Author, if both of them are not used, and I run swagger flatten --with-flatten=remove-unused then it will only remove Book model, but will keep Author as it was considered as used, but it's not really used anymore.

Steps to reproduce

1. Let's say you have this simple schema.json

{
  "consumes": [
    "application/json"
  ],
  "produces": [
    "application/json"
  ],
  "schemes": [
    "http",
    "https"
  ],
  "swagger": "2.0",
  "info": {
    "title": "Sample API.",
    "version": "1.0.0"
  },
  "paths": {
    "/hello": {
      "get": {
        "description": "Hello",
        "operationId": "hello",
        "responses": {
          "200": {
            "description": "success"
          }
        }
      }
    }
  },
  "definitions": {
    "Author": {
      "type": "object",
      "properties": {
        "name": {
          "type": "string"
        }
      }
    },
    "Book": {
      "type": "object",
      "properties": {
        "author": {
          "$ref": "#/definitions/Author"
        }
      }
    }
  }
}

as you can see Author and Book are not referenced by any route, however Book references Author.

2. run swagger flatten --with-flatten=remove-unused -o=schema.json schema.json
   The update schema.json does not have Book anymore as expected, but still has the Author, which is not really being used as well. So Author should have been removed as well but it was not.

Temporary Solution

You can run swagger flatten --with-flatten=remove-unused -o=schema.json schema.json one more time and Author will be removed, but ideally this tool should be able to remove all unused definitions in one single execution.

Environment

swagger version: 0.26.1
go version: 1.17
OS: macOS