Here’s a well-structured bug report you can submit to the springdoc-openapi GitHub repository:

Bug Report: Private Inner Class SpecificationStringPropertiesCustomizerBeanPostProcessor Inaccessible During AOT/Native Compilation

Description

When building a GraalVM native image with springdoc-openapi (v2.5.0+) and Spring Boot 3.x, the AOT compiler fails with the following error:

/build/generated/aotSources/org/springdoc/core/configuration/SpringDocSpecPropertiesConfiguration__BeanDefinitions.java:48: error: SpecificationStringPropertiesCustomizerBeanPostProcessor has private access in SpringDocSpecPropertiesConfiguration
private static BeanInstanceSupplier<SpringDocSpecPropertiesConfiguration.SpecificationStringPropertiesCustomizerBeanPostProcessor> getSpecificationStringPropertiesCustomizerBeanPostProcessorInstanceSupplier(

The issue occurs because the AOT-generated code cannot access the private inner class SpecificationStringPropertiesCustomizerBeanPostProcessor in SpringDocSpecPropertiesConfiguration.

Steps to Reproduce

1. Environment:

   • Spring Boot: 3.4.4
   • SpringDoc OpenAPI: 2.5.0 (or 2.8.6)
   • GraalVM Native:
     openjdk version "21.0.2" 2024-01-16 OpenJDK Runtime Environment GraalVM CE 21.0.2+13.1 (build 21.0.2+13-jvmci-23.1-b30) OpenJDK 64-Bit Server VM GraalVM CE 21.0.2+13.1 (build 21.0.2+13-jvmci-23.1-b30, mixed mode, sharing)
   • Java: 21

2. Reproduction Steps:

   • Create a Spring Boot 3.x project with springdoc-openapi-starter-webmvc-ui.
   • Enable GraalVM native image compilation (org.graalvm.buildtools.native).
   • Run:

     ./gradlew nativeCompile

   • Result: Build fails with the above error.

3. Minimal Test Case:

   @SpringBootApplication
   public class DemoApplication {
       public static void main(String[] args) {
           SpringApplication.run(DemoApplication.class, args);
       }
   }

   (No explicit OpenAPI config needed—fails with default setup.)

Expected Behavior

• The native image compilation should succeed, as springdoc-openapi should support Spring AOT and GraalVM native builds.

• The SpecificationStringPropertiesCustomizerBeanPostProcessor should either be public or use a different mechanism for AOT compatibility.

• Impact:

  • Blocks native image adoption for projects using springdoc-openapi.

Request

• Could the SpecificationStringPropertiesCustomizerBeanPostProcessor be made public or modified for AOT compatibility?
• Alternatively, could an official GraalVM native image hint be provided?