[BUG] html2 generator: some schemas are generated empty

[OnkelTem]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?

Description

I'm trying to generate API docs for our API. I run html2 generator but it returns blank space where schemas should go.

openapi-generator version

5.3.1

OpenAPI declaration file content or url

I'm afraid I cannot provide the full API as it's covered by NDA. But here is a snippet for which schemas are not generated:

  /inputs:
    get:
      summary: All inputs data
      description: Returns a list of currently configured inputs
      operationId: inputsGet
      security:
        - bearerAuth: []
      tags:
        - inputs
      responses:
        '200':
          description: Successful operation
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Inputs'
        '401':
          $ref: '#/components/responses/Unauthorized'
        default:
          $ref: '#/components/responses/Error'
#...
    Inputs:
      type: array
      items:
        $ref: '#/components/schemas/Input'
    Input:
      type: object
      required:
        - input_id
        - name
        - config
        - alerts_config
      properties:
        input_id:
          type: integer
        name:
          type: string
        # ...

It's just a regular API with paths and schemas. Nothing special.

It has perfectly generated code for more than 2 years. Recently we decided to generate docs using one of the html generators provided by this tool. GitLab renders the API using swagger w/o any problems.

Generation Details

We generate with html2 generator.

Steps to reproduce

The generator is launched with the following params:

$ npx openapi-generator-cli generate -i api_openapi.yaml -g html2 -o docs/api/

and it outputs empty schemas. Not all of them are empty, but most.

[hauntingEcho]

Is this issue only when using $ref to define the structures (i.e. if you inline them then it works)? If so, I've been seeing similar issues: #11027

[madelinekosse]

I have also run into this issue: the outer level of the schema is correctly generated, but the property schemas are not, even when I define them inline.

For the following response schema:

responses:
        '200':
          description: Details about the registration given by the ID parameter
          content:
            application/json:
              schema:
                type: object
                properties:
                  meta:
                    type: object
                  items:
                    type: array
                    minItems: 1
                    maxItems: 1
                    items:
                      type: object
                      properties:
                        anInlineProperty:
                          type: string
                        anInlineObject:
                          type: object
                          properties:
                            id:
                              type: integer
                            name:
                              type: string

The html2 generator, with no customisation, produces the following:

[MapleWolf64]

Issue happens again with version 6.2.0
ok with version 6.1.0

[harish2704]

Hi,
I iterated through all previous versions and found that this bug does not exists with version 5.4.0
So, a workaround for this bug is to issue following command in our terminal

openapi-generator-cli version-manager set 5.4.0

( I downgraded my version from 6.2.0 to 5.4.0 )

[cgm-aw]

I can confirm this bug. Here is my reproducer:

{https://docs.github.com/github/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax
    "openapi": "3.0.1",
    "info": {
        "title": "Reproducer API for missing response schemas",
        "version": "0.0.1"
    },
    "paths": {
        "/appointments/{id}": {
            "get": {
                "summary": "test 1",
                "parameters": [
                    {
                        "name": "id",
                        "in": "path",
                        "required": true,
                        "schema": {
                            "type": "string"
                        }
                    }
                ],
                "responses": {
                    "200": {
                        "description": "successful operation",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "$ref": "#/components/schemas/GetAppointmentsResponse"
                                }
                            }
                        }
                    },
                    "400": {
                        "description": "client error, probably a wrong request"
                    },
                    "500": {
                        "description": "server error, probably a temporary problem"
                    }
                }
            }
        }
    },
    "components": {
        "schemas": {
            "GetAppointmentsResponse": {
                "type": "object",
                "properties": {
                    "appointmentId": {
                        "type": "string"
                    }
                }
            }
        }
    }
}

openapi-generator-cli with html2 produces this:

[r-gruber]

This problem still exists even in latest nightly build: openapi-generator-cli-6.5.0-20230302.132003-21.jar

Here is a simple test file:

openapi: '3.0.3'
info:
  title: 'Dummy'
  version: 1.0.0
servers:
- url: https://dummy/v1
tags:
  - name: DummyService
paths:
  '/info/{inDummyParam}':
    get:
      tags:
        - DummyService
      summary: 'Retrieve data'
      operationId: getDummy
      parameters:
        - $ref: '#/components/parameters/inDummyParam'
      responses:
        '200':
          description: 'Successful operation'
          content:
            application/json:
              schema:
                 $ref: '#/components/schemas/Ok2Dto'
        '400':
          description: 'Error'
          content:
            application/json:
              schema:
                 type: string
components:
  parameters:
    inDummyParam:
      name: inDummyParam
      in: path
      required: true
      schema:
        type: string
  schemas:
    Ok2Dto:
      description: 'Data set for information on a specific loading unit.'
      type: object
      required:
        - prop1
        - prop2
      properties:
        prop1:
          type: string
          description: Unique ID
        prop2:
          type: string
          description: Something else

Tested with latest nightly build version:
java -jar openapi-generator-cli-6.5.0-20230302.132003-21.jar generate -g html2 -i test.yaml -o htmlNightly
results in incorrect "Responses":

Tested with old 6.1.0 version:
java -jar openapi-generator-cli-6.1.0.jar generate -g html2 -i test.yaml -o html61
results in correct output:

[r-gruber]

I can confirm that in version 6.2.0 it is already broken.
So somewhere between 6.1.0 and 6.2.0 the bug was introduced.

[wogri]

I can confirm this is broken on 6.5.0 as well.

[stuartford]

All of my Schema tabs are now blank with 6.6.0.

[VeXell]

Same for me

[paranat]

Still broken as of 7.3.0