OpenApiCustomizer overridden by OperationIdCustomizer when both are defined

[johnycho]

Describe the bug

When I define a custom OpenApiCustomizer to customize the OpenAPI metadata (info, servers) using external properties, the values set in the customizer are not reflected in the final OpenAPI output.
I confirmed that the OpenApiCustomizer is invoked, but its settings appear to be overwritten — possibly by OperationIdCustomizer or another internal component.

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To Reproduce

• Spring Boot version: 3.5.2

• springdoc-openapi version:

  implementation 'org.springdoc:springdoc-openapi-starter-webmvc-ui:2.8.9'

• application.yml

  springdoc:
    custom:
      title: joy admin api
      version: v1.0.1
      servers:
        - url: http://localhost:8081
          description: local

• Spring Configuration:

  @Configuration
  @EnableConfigurationProperties(SpringDocProperties.class)
  @RequiredArgsConstructor
  public class SpringDocConfig {
  
    private final SpringDocProperties springDocProperties;
  
    @Bean
    OpenApiCustomizer commonOpenApiCustomizer() {
      return openApi -> openApi.servers(servers())
                               .info(info());
    }
  
    private List<Server> servers() {
      return springDocProperties.getServers()
                                .stream()
                                .map(s -> new Server().url(s.getUrl()).description(s.getDescription()))
                                .toList();
    }
  
    private Info info() {
      return new Info()
          .title(springDocProperties.getTitle())
          .version(springDocProperties.getVersion());
    }
  }

• Property Binding Class:

  @Configuration
  @ConfigurationProperties("springdoc.custom")
  @Data
  public class SpringDocProperties {
  
    private String title = "API";
    private String version = "v0.0.1";
    private List<ServerInfo> servers = List.of();
  
    @Data
    public static class ServerInfo {
      private String url;
      private String description;
    }
  }

• Actual Behavior:

  When accessing http://localhost:8081/v3/api-docs/springdocDefault, the OpenAPI spec still shows:

  {
    "info": {
      "title": "OpenAPI definition",
      "version": "v0"
    }
  }

  Even though OpenApiCustomizer should set it to:

  {
    "title": "joy admin api",
    "version": "v1.0.1"
  }

• Expected Behavior:

  The customizer should override the OpenAPI.info() and OpenAPI.servers() sections. However, the current behavior suggests that these values are reset later in the pipeline.

• Workaround:

  If I define a full @Bean OpenAPI customOpenAPI(), it works as expected:

  @Bean
  public OpenAPI customOpenAPI() {
    return new OpenAPI()
        .info(new Info().title(springDocProperties.getTitle()).version(springDocProperties.getVersion()));
  }

  But this defeats the purpose of using OpenApiCustomizer.

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Screenshots

Not applicable — reproducible via JSON inspection at /v3/api-docs.

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Additional context

This might be related to OperationIdCustomizer or another internal component that applies a new OpenAPI.info() object, thereby discarding the result from the customizer.

Would be helpful to clarify precedence between customizers and internal configurations — or provide a way to prevent overwriting custom OpenApiCustomizer behavior.

[Mattias-Sehlstedt]

Hi, thanks for the elaborate details, it helps greatly in trying to reproduce the issue. I have written a test for the case and it behaves as expected. Could you provide more details/extend the test so that it is possible to reproduce the scenario where then openapi configuration is not propagated?

The OperationIdCustomizer should not interfere with the Info section of an OpenAPI object, so I assume the issue stems from elsewhere.

Given that you suggest http://localhost:8081/v3/api-docs/springdocDefault as the path rather than http://localhost:8081/v3/api-docs/, I assume you might be configuring grouped apis? If so, then "but not on groups" for here might be the cause of the confusion?