[OpenAPI] Duplicated object definitions in openapi spec

[januszj]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

When using two classes as result from minimal api, that are using same class, openapi definition contains two copies of the object for example: WeatherForecast and WeatherForecast2.

"components": {
    "schemas": {
      "WeatherForecast": {
        "required": [
          "date",
          "temperatureC",
          "summary"
        ],
        "type": "object",
        "properties": {
          "date": {
            "type": "string",
            "format": "date"
          },
          "temperatureC": {
            "type": "integer",
            "format": "int32"
          },
          "summary": {
            "type": "string",
            "nullable": true
          },
          "temperatureF": {
            "type": "integer",
            "format": "int32"
          }
        },
        "nullable": true
      },
      "WeatherForecast2": {
        "required": [
          "date",
          "temperatureC",
          "summary"
        ],
        "type": "object",
        "properties": {
          "date": {
            "type": "string",
            "format": "date"
          },
          "temperatureC": {
            "type": "integer",
            "format": "int32"
          },
          "summary": {
            "type": "string",
            "nullable": true
          },
          "temperatureF": {
            "type": "integer",
            "format": "int32"
          }
        }
      },

I created reproduction sample code.

WebApplication3.zip

Expected Behavior

It should generated schema with one WeatherForecast.

Steps To Reproduce

Run repo project, open scalar and click Download OpenAPI Document

Exceptions (if any)

No response

.NET Version

9.0.5

Anything else?

No response

[captainsafia]

Fixed in .NET 10.

#:sdk Microsoft.NET.Sdk.Web
#:property TargetFramework=net10.0
#:property PublishAoT=false
#:package Microsoft.AspNetCore.OpenApi@10.0.0-preview.7.*
#:package Scalar.AspNetCore@2.6.4

using Scalar.AspNetCore;

var builder = WebApplication.CreateBuilder(args);

// Learn more about configuring OpenAPI at https://aka.ms/aspnet/openapi
builder.Services.AddOpenApi();

var app = builder.Build();

// Configure the HTTP request pipeline.

  app.MapOpenApi();
  app.MapScalarApiReference(options =>
  {
    options.Servers = [];
    options.Theme = ScalarTheme.BluePlanet;
  });

app.UseHttpsRedirection();

var summaries = new[]
{
    "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
};
var group = app
        .MapGroup("/serviceprograms")
        .WithTags("WeatherForecast")
        .WithOpenApi();

group.MapGet("/weatherforecast", (HttpContext httpContext) =>
{
  var forecast = Enumerable.Range(1, 5).Select(index =>
      new WeatherForecast
      (
          DateOnly.FromDateTime(DateTime.Now.AddDays(index)),
          Random.Shared.Next(-20, 55),
          summaries[Random.Shared.Next(summaries.Length)]
      ))
      .ToArray();

  var wr = new WeatherResponse();
  wr.Payload = forecast[0];

  return wr;
})
.WithName("GetWeatherForecast")
.Produces<WeatherResponse>(StatusCodes.Status200OK)
.WithOpenApi();

group.MapGet("/weatherforecasts", (HttpContext httpContext) =>
{
  var forecast = Enumerable.Range(1, 5).Select(index =>
      new WeatherForecast
      (
          DateOnly.FromDateTime(DateTime.Now.AddDays(index)),
          Random.Shared.Next(-20, 55),
          summaries[Random.Shared.Next(summaries.Length)]
      ))
      .ToArray();
  var wsr = new WeathersResponse();
  wsr.Payload = forecast.ToList();

  return wsr;
})
.WithName("GetWeatherForecasts")
.Produces<WeathersResponse>(StatusCodes.Status200OK)
.WithOpenApi();

app.Run();

public record WeatherForecast(DateOnly Date, int TemperatureC, string? Summary)
{
  public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
}

public class WeatherResponse
{
  public WeatherForecast? Payload { get; set; }
}

public class WeathersResponse
{
  public List<WeatherForecast>? Payload { get; set; }
}

{
  "openapi": "3.1.1",
  "info": {
    "title": "62345 | v1",
    "version": "1.0.0"
  },
  "servers": [
    {
      "url": "http://localhost:5000/"
    }
  ],
  "paths": {
    "/serviceprograms/weatherforecast": {
      "get": {
        "tags": [
          "WeatherForecast"
        ],
        "operationId": "GetWeatherForecast",
        "responses": {
          "200": {
            "description": "OK",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/WeatherResponse"
                }
              }
            }
          }
        }
      }
    },
    "/serviceprograms/weatherforecasts": {
      "get": {
        "tags": [
          "WeatherForecast"
        ],
        "operationId": "GetWeatherForecasts",
        "responses": {
          "200": {
            "description": "OK",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/WeathersResponse"
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "WeatherForecast": {
        "required": [
          "date",
          "temperatureC",
          "summary"
        ],
        "type": "object",
        "properties": {
          "date": {
            "type": "string",
            "format": "date"
          },
          "temperatureC": {
            "pattern": "^-?(?:0|[1-9]\\d*)$",
            "type": [
              "integer",
              "string"
            ],
            "format": "int32"
          },
          "summary": {
            "type": [
              "null",
              "string"
            ]
          },
          "temperatureF": {
            "pattern": "^-?(?:0|[1-9]\\d*)$",
            "type": [
              "integer",
              "string"
            ],
            "format": "int32"
          }
        }
      },
      "WeatherResponse": {
        "type": "object",
        "properties": {
          "payload": {
            "$ref": "#/components/schemas/WeatherForecast"
          }
        }
      },
      "WeathersResponse": {
        "type": "object",
        "properties": {
          "payload": {
            "type": [
              "null",
              "array"
            ],
            "items": {
              "$ref": "#/components/schemas/WeatherForecast"
            }
          }
        }
      }
    }
  },
  "tags": [
    {
      "name": "WeatherForecast"
    }
  ]
}