MS OpenAPI does not generate a valid schema for nullable complex properties

[luisabreu]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

The new OpenAPI support for ASP.NET Core projects generates semantic errors for some types, specifically for $ref entries. The sample below reproduces the issue: one of the properties gets the following ref: "$ref" "#/components/schemas/#/properties/locaisRemover/items/properties/locais" which produces invalid description.

Expected Behavior

No response

Steps To Reproduce

Here's a sample that reproduces the issue by using and :

using Microsoft.AspNetCore.Http.HttpResults;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
// Learn more about configuring OpenAPI at https://aka.ms/aspnet/openapi
builder.Services.AddOpenApi( );
var app = builder.Build( );

// Configure the HTTP request pipeline.
if( app.Environment.IsDevelopment( ) ) {
    app.MapOpenApi( );
}
app.UseHttpsRedirection( );

app.MapPut("/test",
           (MsgMovimentacaoLocaisTrabalho msg) => Results.Ok( ))
   .WithName("GetWeatherForecast");

app.Run( );


public class MsgMovimentacaoLocaisTrabalho {    
    public IList<InfoGeral>? LocaisRemover { get; set; }
    public InfoGeral? LocaisAssociar { get; set; }
}

public class InfoGeral {    
    public Guid GuidDirecao { get; set; }
    public IEnumerable<int> Locais { get; set; } = Enumerable.Empty<int>();
}

Exceptions (if any)

No response

.NET Version

9.0.101

Anything else?

No response

[marcominerva]

I can confirm that the issue still happens with .NET 9.0.2

[captainsafia]

The relative reference is mapped correctly to the parent schema in .NET 10.

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

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
// 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.UseHttpsRedirection();

app.MapPut("/test",
           (MsgMovimentacaoLocaisTrabalho msg) => Results.Ok())
   .WithName("GetWeatherForecast");

app.Run();


public class MsgMovimentacaoLocaisTrabalho
{
    public IList<InfoGeral>? LocaisRemover { get; set; }
    public InfoGeral? LocaisAssociar { get; set; }
}

public class InfoGeral
{
    public Guid GuidDirecao { get; set; }
    public IEnumerable<int> Locais { get; set; } = Enumerable.Empty<int>();
}

{
  "openapi": "3.1.1",
  "info": {
    "title": "59976 | v1",
    "version": "1.0.0"
  },
  "servers": [
    {
      "url": "http://localhost:5000/"
    }
  ],
  "paths": {
    "/test": {
      "put": {
        "tags": [
          "59976"
        ],
        "operationId": "GetWeatherForecast",
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/MsgMovimentacaoLocaisTrabalho"
              }
            }
          },
          "required": true
        },
        "responses": {
          "200": {
            "description": "OK"
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "InfoGeral": {
        "type": [
          "null",
          "object"
        ],
        "properties": {
          "guidDirecao": {
            "type": "string",
            "format": "uuid"
          },
          "locais": {
            "$ref": "#/components/schemas/MsgMovimentacaoLocaisTrabalho/properties/locaisRemover/items/properties/locais"
          }
        }
      },
      "MsgMovimentacaoLocaisTrabalho": {
        "type": "object",
        "properties": {
          "locaisRemover": {
            "type": [
              "null",
              "array"
            ],
            "items": {
              "$ref": "#/components/schemas/InfoGeral"
            }
          },
          "locaisAssociar": {
            "$ref": "#/components/schemas/InfoGeral"
          }
        }
      }
    }
  },
  "tags": [
    {
      "name": "59976"
    }
  ]
}