Authorize in Swagger UI no longer works, starting in v2.8.4

[magnus-larsson]

Describe the bug

• Using the Authorize button in Swagger UI no longer works; the bug is introduced in v2.8.4

To Reproduce

I have created a minimal project to reproduce the error. It consists of:

• An auth server
• An API
• A Spring Cloud Gateway

Steps to reproduce the behavior:

1. Verify that login works in swagger-ui with springdoc-openapi 2.8.3:

   Get the source code:

   git clone https://github.com/magnus-larsson/ml-auth-server-error.git
   cd ml-auth-server-error
   

   Build and start the auth server, the API, and the gateway:

   ./gradlew build
   docker compose up -d --build
   

   Open the Swagger UI and login:

   1. Open in a web browser: https://localhost:8443/openapi/swagger-ui.html
   2. Click on the Authorize button
   3. Select all available scopes
   4. Sign in using username u and password p
   5. Select all scopes and submit consent
   6. Login done

2. Update to springdoc-openapi 2.8.5 in product-composite-service/build.gradle and repeat the instruction above.

   1. After the sign in, an errorpage with the following text will now be displayed:

      Whitelabel Error Page
      
      This application has no explicit mapping for /error, so you are seeing this as a fallback.
      
      Sat Mar 08 16:01:11 UTC 2025
      There was an unexpected error (type=None, status=999).
      

[bnasslahsen]

@magnus-larsson,

I understand your concern for this breaking change. In addition, it's not well documented.
This is related to this change #2862, to can align Swagger-WebFlux
Swagger-UI Prefix Path with Swagger-WebMvc

To fix your project, the better option is to remove the webjars prefix, from:

• https://github.com/magnus-larsson/ml-auth-server-error/blob/174d2252b213668e855a97793331e06589f881c7/authorization-server/src/main/java/sample/config/AuthorizationServerConfig.java#L134
  And:
• https://github.com/magnus-larsson/ml-auth-server-error/blob/174d2252b213668e855a97793331e06589f881c7/authorization-server/src/main/java/sample/config/AuthorizationServerConfig.java#L118

The new redirect url will be: https://localhost:8443/openapi/swagger-ui/oauth2-redirect.html

[magnus-larsson]

@bnasslahsen Thanks for your help!

I have pushed a working solution in the branch v2.8.6-OK, where I removed webjars and upgraded to the latest version of springdoc-openapi, v2.8.6.