Broken generated code for OPENAPI tictactoe example

[timosturm]

Description of the bug

Generating the api code for the tictactoe example from OPENAPI generates broken code:

class Mark {
  /// Returns a new [Mark] instance.
  Mark({
  });

  @override
  bool operator ==(Object other) => identical(this, other) || other is Mark &&

  @override
  int get hashCode =>
    // ignore: unnecessary_parenthesis

...
}

and

class Winner {
  /// Returns a new [Winner] instance.
  Winner({
  });

  @override
  bool operator ==(Object other) => identical(this, other) || other is Winner &&

  @override
  int get hashCode =>
    // ignore: unnecessary_parenthesis

...
}

Steps to reproduce

@Openapi(
    additionalProperties: AdditionalProperties(
      pubName: 'tictactoe_api',
      pubAuthor: 'Jon Doe',
      pubAuthorEmail: "me@example.com"
    ),
    inputSpecFile: 'tictactoe.yaml',
    generatorName: Generator.dart,
    outputDirectory: 'api/tictactoe_api')
class TicTacToe extends OpenapiGeneratorConfig {}

tictactoe.yaml:

openapi: 3.1.0
info:
  title: Tic Tac Toe
  description: |
    This API allows writing down marks on a Tic Tac Toe board
    and requesting the state of the board or of individual squares.
  version: 1.0.0
tags:
  - name: Gameplay
paths:
  # Whole board operations
  /board:
    get:
      summary: Get the whole board
      description: Retrieves the current state of the board and the winner.
      tags:
        - Gameplay
      operationId: get-board
      responses:
        "200":
          description: "OK"
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/status"

  # Single square operations
  /board/{row}/{column}:
    parameters:
      - $ref: "#/components/parameters/rowParam"
      - $ref: "#/components/parameters/columnParam"
    get:
      summary: Get a single board square
      description: Retrieves the requested square.
      tags:
        - Gameplay
      operationId: get-square
      responses:
        "200":
          description: "OK"
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/mark"
        "400":
          description: The provided parameters are incorrect
          content:
            text/html:
              schema:
                $ref: "#/components/schemas/errorMessage"
              example: "Illegal coordinates"
    put:
      summary: Set a single board square
      description: Places a mark on the board and retrieves the whole board and the winner (if any).
      tags:
        - Gameplay
      operationId: put-square
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/mark"
      responses:
        "200":
          description: "OK"
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/status"
        "400":
          description: The provided parameters are incorrect
          content:
            text/html:
              schema:
                $ref: "#/components/schemas/errorMessage"
              examples:
                illegalCoordinates:
                  value: "Illegal coordinates."
                notEmpty:
                  value: "Square is not empty."
                invalidMark:
                  value: "Invalid Mark (X or O)."

components:
  parameters:
    rowParam:
      description: Board row (vertical coordinate)
      name: row
      in: path
      required: true
      schema:
        $ref: "#/components/schemas/coordinate"
    columnParam:
      description: Board column (horizontal coordinate)
      name: column
      in: path
      required: true
      schema:
        $ref: "#/components/schemas/coordinate"
  schemas:
    errorMessage:
      type: string
      maxLength: 256
      description: A text message describing an error
    coordinate:
      type: integer
      minimum: 1
      maximum: 3
      example: 1
    mark:
      type: string
      enum: [".", "X", "O"]
      description: Possible values for a board square. `.` means empty square.
      example: "."
    board:
      type: array
      maxItems: 3
      minItems: 3
      items:
        type: array
        maxItems: 3
        minItems: 3
        items:
          $ref: "#/components/schemas/mark"
    winner:
      type: string
      enum: [".", "X", "O"]
      description: Winner of the game. `.` means nobody has won yet.
      example: "."
    status:
      type: object
      properties:
        winner:
          $ref: "#/components/schemas/winner"
        board:
          $ref: "#/components/schemas/board"

Expected behavior

Non-broken code.

Logs

dart run build_runner build --delete-conflicting-outputs                                                                    ✔ 
[INFO] Generating build script completed, took 248ms
[INFO] Reading cached asset graph completed, took 45ms
[INFO] Checking for updates since last build completed, took 423ms
[WARNING] openapi_generator on lib/openapi_test.dart:
OpenapiGenerator :: [generate -i tictactoe.yaml -g dart -o api/tictactoe_api --additional-properties=pubName=tictactoe_api,pubAuthor=Jon Doe,pubAuthorEmail=me@example.com]
[WARNING] openapi_generator on lib/openapi_test.dart:
------------------------------------------------------
|                                                     |
|             Openapi generator for dart              |
|                                                     |
|                                                     |
------------------------------------------------------
[WARNING] openapi_generator on lib/openapi_test.dart:
Executing command [generate -i tictactoe.yaml -g dart -o api/tictactoe_api --additional-properties=pubName=tictactoe_api,pubAuthor=Jon Doe,pubAuthorEmail=me@example.com]
[WARNING] openapi_generator on lib/openapi_test.dart:

[WARNING] openapi_generator on lib/openapi_test.dart:
OpenapiGenerator :: Codegen completed successfully
[WARNING] openapi_generator on lib/openapi_test.dart:

[WARNING] openapi_generator on lib/openapi_test.dart:
OpenapiGenerator :: Install exited with code 0
[WARNING] openapi_generator on lib/openapi_test.dart:
OpenapiGenerator :: skipping source gen because generator does not need it ::
[INFO] Running build completed, took 4.4s
[INFO] Caching finalized dependency graph completed, took 29ms
[INFO] Succeeded after 4.5s with 0 outputs (1 actions)

Screenshots

No response

Platform

Linux

Library version

4.10.0

dart version

3.0.1

Flutter channel

stable

Additional context

using build_runner: ^2.4.4