[BUG] Spring boot 3 - can't see interfaces with default methods. "Ignored because not a concrete top-level class"

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• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
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Description

I'm moving to spring boot 3, generating the interface only classes, all annotations work correctly.
When starting in spring the class is scanned, but for the generated interfaces with default methods
spring logs ::

o.s.c.a.ClassPathBeanDefinitionScanner : Ignored because not a concrete top-level class:

I've tested with spring boot versions 3.0.x 3.1.x and 3.2.x and the same issue appears

openapi-generator version

7.4.0

Generation Details

org.openapitools openapi-generator-maven-plugin 7.4.0 generate ${project.build.directory}/classes/contract/contract.yaml spring true ApiUtil.java

                        <generateApis>true</generateApis>
                        <generateApiTests>false</generateApiTests>
                        <generateModelTests>false</generateModelTests>

                        <apiPackage>true</apiPackage>
                        <modelPackage>true</modelPackage>
                        <apiPackage>com.api</apiPackage>
                        <modelPackage>com.model</modelPackage>
                        <modelNameSuffix></modelNameSuffix>

                        <output>${project.build.directory}/generated-sources</output>
                        <configOptions>
                            
                            <useResponseEntity>true</useResponseEntity>

                            <enablePostProcessFile>true</enablePostProcessFile>
                            <interfaceOnly>true</interfaceOnly>
                            <java8>true</java8>
                            <sourceFolder>openapi</sourceFolder>
                            <dateLibrary>java8</dateLibrary>
                            <useSpringBoot3>true</useSpringBoot3>
                            <useSpringController>true</useSpringController>
                            <library>spring-boot</library>
                            <useTags>true</useTags>
                            <templateDirectory>src/main/resources/mustache</templateDirectory>
                            <useBeanValidation>true</useBeanValidation>
                            <performBeanValidation>true</performBeanValidation>
                            <useOptional>true</useOptional>
                            <hideGenerationTimestamp>true</hideGenerationTimestamp>
                            <unhandledException>true</unhandledException>
                            <useSwaggerUI>false</useSwaggerUI>
                            <annotationLibrary>none</annotationLibrary>
                            <documentationProvider>none</documentationProvider>

                        </configOptions>
                    </configuration>
                </execution>
            </executions>
        </plugin>

Steps to reproduce

Generate the interface as normal from the contract (my generator config is above)

enable spring logging to see

logging.level.org.springframework.core.io.support=DEBUG
logging.level.org.springframework.context.annotation=DEBUG

Watch the interface be ignored.

Related issues/PRs

none I can see

Suggest a fix

You need to implement your interfaces, and annotate them with @RestController
you don't need any other annotation.
The default interface methods sadly will be ignored.

Begin with the spring generator selected by generatorName=spring and the interfaceOnly and useSpringBoot3 options in the Maven configuration. Reproduce the generation and inspect the resulting interfaces and Spring scan logs; done means the generated API interfaces are implemented and annotated so Spring no longer ignores them.