Swagger UI Could not resolve reference: Could not resolve pointer: After upgrading to SwashBuckle 6.3.0 with latest Swagger UI

[PTAdvanced]

I am experiencing an issue with the Swagger UI after upgrading from Swashbuckle 6.2.3 to 6.3.0.

After some investigation, the issue appears to be with Swagger UI and not the swagger.json document generated by Swashbuckle, hence my posting here.

When navigating to the Swagger UI, and expanding one of my methods, the "Example Value | Schema" section simply displays

"string"

At the top of the Swagger UI a message appears:

Resolver error at paths./request/requestsingledevicefromsite.post.requestBody.content.application/json.schema.$ref Could not resolve reference: Could not resolve pointer: /components/schemas/Advanced.Cloud.Live.DomainModel.FireSystemDigitalTwin.Sychronisation.OutboundRequest.CQRS.RequestStatusOfSingleDeviceAtSite+Command does not exist in document

I browsed the generated swagger.json document, and looked for the "Advanced.Cloud.Live.DomainModel.FireSystemDigitalTwin.Sychronisation.OutboundRequest.CQRS.RequestStatusOfSingleDeviceAtSite+Command" reference.

I find it within the "paths" object, and see that the "$ref" property is pointing to the "Advanced.Cloud.Live.DomainModel.FireSystemDigitalTwin.Sychronisation.OutboundRequest.CQRS.RequestStatusOfSingleDeviceAtSite+Command" object.

"/request/requestsingledevicefromsite": {
  "post": {
    "tags": [
      "FireSystemRequest"
    ],
    "operationId": "RequestSingleDeviceFromSite",
    "requestBody": {
      "content": {
        "application/json": {
          "schema": {
            "$ref": "#/components/schemas/Advanced.Cloud.Live.DomainModel.FireSystemDigitalTwin.Sychronisation.OutboundRequest.CQRS.RequestStatusOfSingleDeviceAtSite+Command"
          }
        }
      }
    },
    "responses": {
      "201": {
        "description": "Created"
      },
      "401": {
        "description": "Unauthorized",
        "content": {
          "application/json": {
            "schema": {
              "$ref": "#/components/schemas/Microsoft.AspNetCore.Mvc.ProblemDetails"
            }
          }
        }
      },
      "400": {
        "description": "Bad Request",
        "content": {
          "application/json": {
            "schema": {
              "$ref": "#/components/schemas/Microsoft.AspNetCore.Mvc.ProblemDetails"
            }
          }
        }
      },
      "403": {
        "description": "Forbidden"
      }
    }
  }
},

Further down the swagger.json document, the reference is located, within the "components" / "schemas" section:

"Advanced.Cloud.Live.DomainModel.FireSystemDigitalTwin.Sychronisation.OutboundRequest.CQRS.RequestStatusOfSingleDeviceAtSite+Command": {
        "type": "object",
        "properties": {
          "SiteId": {
            "type": "string",
            "format": "uuid"
          },
          "NodeId": {
            "type": "integer",
            "format": "int32"
          },
          "Loop": {
            "type": "integer",
            "format": "int32"
          },
          "Address": {
            "type": "integer",
            "format": "int32"
          },
          "SubAddress": {
            "type": "integer",
            "format": "int32"
          }
        },
        "additionalProperties": false
      },

I downloaded the swagger.json generated by both the v6.2.3 and v6.3.0 Swashbuckle, performing a text diff on the 2 files. They are almost identical, apart from the HTTP 201 responses having a description of "Success" in the v6.2.3 document and "Created" in the v6.3.0 document.

I believe Swashbuckle recently upgraded from Swagger UI 4.1.3 to 4.5.0

[PTAdvanced]

The issue seems to be due to the + in the Schema ref name.

I had configured the SwaggerGen as follows:

services.AddSwaggerGen(c =>
{
    c.CustomSchemaIds(s => s.FullName);
    ...
}

But modifying as:

services.AddSwaggerGen(c =>
{
    c.CustomSchemaIds(s => s.FullName.Replace("+", "."));
}

generates a schema $ref without the +

Swagger UI did not seem to have an issue with the + in the $ref name previously.

[steveblomeley]

Thanks for this, found the same issue in our fairly complex production API and this fixed it. Bizarrely, when I created a new bare bones webapi project, then added an endpoint that uses a nested ".Command" class for the request body, the Swagger page works fine using Swashbuckle 6.3.1, despite the underlying JSON schema specifying the "ParentClass+Command" format. Very odd.

[ClassyCircuit]

Why isn't this fixed?!

[huesla]

Have the same issue with Swashbuckle.AspNetCore 6.4.0

[CodyBatt]

Same with 6.5.0

[enzoeuler]

Fixed with

builder.Services.AddSwaggerGen(options => { options.CustomSchemaIds(type => type.ToString()); });

[Uleertel]

The issue seems to be due to the + in the Schema ref name.

I had configured the SwaggerGen as follows:

services.AddSwaggerGen(c =>
{
    c.CustomSchemaIds(s => s.FullName);
    ...
}

But modifying as:

services.AddSwaggerGen(c =>
{
    c.CustomSchemaIds(s => s.FullName.Replace("+", "."));
}

generates a schema $ref without the +

Swagger UI did not seem to have an issue with the + in the $ref name previously.

We are using Swashbuckle.AspNetCore 6.5.0 on a .NET 7 project and I had to use this solution to avoid errors with Nested types. Is there a better fixe since this message that is one year old? thx.

[EhsanRezaei1981]

Unfortunately, the new version has an issue with the + Thanks for your investigation.

[Serotonindude]

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