During incremental compilation, configuration property metadata isn't generated for classes annotated with @ControllerEndpoint, @JmxEndpoint, @RestControllerEndpoint, @ServletEndpoint, or @WebEndpoint

We’ve seen this a few times when building locally. The build fails like this:

> Task :spring-boot-project:spring-boot-docs:asciidoctor
Feb 22, 2021 9:50:24 AM asciidoctor
WARNING: Configuration property 'management.endpoint.jolokia.enabled' not found.
Exception in thread "main" org.asciidoctor.gradle.remote.AsciidoctorRemoteExecutionException: ERROR: The following messages from AsciidoctorJ are treated as errors:
Configuration property 'management.endpoint.jolokia.enabled' not found.
        at org.asciidoctor.gradle.remote.ExecutorBase.failOnWarnings(ExecutorBase.groovy:223)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:101)
        at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:323)
        at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1217)
        at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1041)
        at org.codehaus.groovy.runtime.InvokerHelper.invokePogoMethod(InvokerHelper.java:1011)
        at org.codehaus.groovy.runtime.InvokerHelper.invokeMethod(InvokerHelper.java:994)
        at org.codehaus.groovy.runtime.InvokerHelper.invokeMethodSafe(InvokerHelper.java:97)
        at org.asciidoctor.gradle.remote.AsciidoctorJavaExec$_run_closure3.doCall(AsciidoctorJavaExec.groovy:74)
        at org.asciidoctor.gradle.remote.AsciidoctorJavaExec$_run_closure3.call(AsciidoctorJavaExec.groovy)
        at org.codehaus.groovy.runtime.DefaultGroovyMethods.each(DefaultGroovyMethods.java:2330)
        at org.codehaus.groovy.runtime.DefaultGroovyMethods.each(DefaultGroovyMethods.java:2315)
        at org.codehaus.groovy.runtime.DefaultGroovyMethods.each(DefaultGroovyMethods.java:2356)
        at org.asciidoctor.gradle.remote.AsciidoctorJavaExec.run(AsciidoctorJavaExec.groovy:67)
        at org.asciidoctor.gradle.remote.AsciidoctorJavaExec.main(AsciidoctorJavaExec.groovy:49)

Our current theory is that it’s a bug in the annotation processor when it’s being run incrementally. In this case, we can see that Asciidoctor ran at 9:50:24. Looking at the file system, the JSON file was written at 09:49:

$ ls -al spring-boot-project/spring-boot-actuator-autoconfigure/build/classes/java/main/META-INF/spring-configuration-metadata.json 
-rw-r--r--  1 awilkinson  staff  87298 22 Feb 09:49 spring-boot-project/spring-boot-actuator-autoconfigure/build/classes/java/main/META-INF/spring-configuration-metadata.json

The build scan shows that spring-boot-actuator-autoconfigure:compileJava ran due to the following changes:

Input property 'classpath' file spring-boot-project/spring-boot-autoconfigure/build/classes/java/main/org/springframework/boot/autoconfigure/jdbc/DataSourceInitialization.class has been removed.
Input property 'classpath' file spring-boot-project/spring-boot-autoconfigure/build/classes/java/main/org/springframework/boot/autoconfigure/jdbc/DataSourceInitializationConfiguration$BeforeJpaDataSourceInitializationConfiguration.class has been added.
Input property 'classpath' file spring-boot-project/spring-boot-autoconfigure/build/classes/java/main/org/springframework/boot/autoconfigure/jdbc/DataSourceInitializationConfiguration$BeforeJpaDataSourceInitializationConfiguration.class has been removed.

The metadata contains the management.endpoint.jolokia group:

{
    "name": "management.endpoint.jolokia",
    "type": "org.springframework.boot.actuate.autoconfigure.jolokia.JolokiaProperties",
    "sourceType": "org.springframework.boot.actuate.autoconfigure.jolokia.JolokiaProperties"
},

It also contains the management.endpoint.jolokia.config property. Note that the group is as a result of processing the @ConfigurationProperties class. When the .enabled property is present, there’s another management.endpoint.jolokia group:

{
  "name": "management.endpoint.jolokia",
  "type": "org.springframework.boot.actuate.autoconfigure.jolokia.JolokiaEndpoint",
  "sourceType": "org.springframework.boot.actuate.autoconfigure.jolokia.JolokiaEndpoint"
},

It appears to be behaving as if the @Endpoint annotation isn’t on the classpath, or the @Endpoint-annotated classes aren’t in the RoundEnvironment.

[wilkinsona]

I think this is much simpler than we’d been thinking. JolokiaEndpoint is a @ServletEndpoint yet the annotation processor only claims support for @Endpoint. When Gradle is compiling incrementally it doesn’t include JolokiaEndpoint in the RoundEnvironment as it isn’t annotated with an annotation that the processor claims to support. We need to add @ServletEndpoint to the supported types declared by ConfigurationMetadataAnnotationProcessor.

[wilkinsona]

2.3.x doesn’t have this problem as it uses *.