Spring-boot: @ConfigurationProperties does not work on @Bean methods in auto-configuration classes when metadata caching is disabled on the bean factory

[arnesacnussem]

Spring Boot version 2.2.0.M6

change the value of spring.messages.basename in application.properties does not make any difference

demo.zip
In this demo,the test com.example.demo.DemoApplicationTests#contextLoads will always fail.

Make a breakpoint at resolveCodeWithoutArguments:151, org.springframework.context.support.ResourceBundleMessageSource#resolveCodeWithoutArguments

The getBasenameSet() will always return a set which only contain one element: "messages"

But if eval the getResourceBundle("msg", locale) at that point,it will return the correct thing.

Also
org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration.ResourceBundleCondition#getResources returns the correct thing.

[snicoll]

@arnesacnussem Thanks for the sample. I ran the test in demo.zip and it worked for me. both on the command line and in my IDE. How do I reproduce the issue?

[arnesacnussem]

found out it happens when using certain jvm
https://github.com/TravaOpenJDK/trava-jdk-11-dcevm/releases/tag/dcevm-11.0.1%2B8

i run into this bug when updating another project from 2.2.0.M1 to 2.2.0.M6,the old version of Spring boot work fine with dcevm.
btw,that project was originally on 2.1.6.RELEASE.

I also tried AdoptOpenJDK 11.0.4 and OracleJDK 1.8.0_201,they all work fine.

[wilkinsona]

Thanks for the additional information.

The failure's occurring because the @ConfigurationProperties annotation isn't found on the messageSourceProperties @Bean method. This appears to be because metadata caching is being disabled on the bean factory. I don't fully understand why this is happening, but I would guess that it's due to some of the hot-swapping support in the custom JVM.

The failure can be reproduced on vanilla OpenJDK using an ApplicationContextInitializer to disable caching:

package com.example.demo;

import java.util.Locale;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.boot.autoconfigure.ImportAutoConfiguration;
import org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration;
import org.springframework.context.ApplicationContextInitializer;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.MessageSource;

@SpringBootConfiguration
@ImportAutoConfiguration(MessageSourceAutoConfiguration.class)
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication application = new SpringApplication(DemoApplication.class);
        application.addInitializers(new ApplicationContextInitializer() {

            @Override
            public void initialize(ConfigurableApplicationContext applicationContext) {
                applicationContext.getBeanFactory().setCacheBeanMetadata(false);

            }

        });
        MessageSource messageSource = application.run(args).getBean(MessageSource.class);
        messageSource.getMessage("content", null, Locale.getDefault());
    }

}

Further investigation is required to determine if this is a Spring Boot problem or a Spring Framework problem.

[wilkinsona]

Here are a couple of Spring Framework tests that illustrate the difference in behaviour:

package example;

import static org.assertj.core.api.Assertions.assertThat;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.ImportSelector;
import org.springframework.core.type.AnnotationMetadata;

class FactoryMethodResolutionTests {

    @Test
    void factoryMethodCanBeResolvedWithBeanMetadataCachingEnabled() {
        assertThatFactoryMethodCanBeResolved(true);
    }

    @Test
    void factoryMethodCanBeResolvedWithBeanMetadataCachingDisabled() {
        assertThatFactoryMethodCanBeResolved(false);        
    }

    private void assertThatFactoryMethodCanBeResolved(boolean cache) {
        try (AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext()) {
            context.getBeanFactory().setCacheBeanMetadata(cache);
            context.register(ImportSelectorConfiguration.class);
            context.refresh();
            BeanDefinition definition = context.getBeanFactory().getMergedBeanDefinition("exampleBean");
            assertThat(((RootBeanDefinition)definition).getResolvedFactoryMethod()).isNotNull();
        }
    }

    @Configuration
    @Import(ExampleImportSelector.class)
    static class ImportSelectorConfiguration {

    }

    static class ExampleImportSelector implements ImportSelector {

        @Override
        public String[] selectImports(AnnotationMetadata importingClassMetadata) {
            return new String[] { TestConfiguration.class.getName() };
        }

    }

    @Configuration
    static class TestConfiguration {

        @Bean
        @ExampleAnnotation
        public ExampleBean exampleBean() {
            return new ExampleBean();
        }

    }

    static class ExampleBean {

    }

    @Target(ElementType.METHOD)
    @Retention(RetentionPolicy.RUNTIME)
    @interface ExampleAnnotation {

    }

}

[wilkinsona]

The Framework tests behave the same way with 5.1 and 5.2, but from a Boot perspective this appears to be a regression. The test above fails with Spring Boot 2.2.0 snapshots but passes with Spring Boot 2.1.8. I think the root cause of that is the fix for https://github.com/spring-projects/spring-boot/issues/16220 where we moved from our own reflective search for the factory method to retrieving it from the bean definition. This relied on some changes in Framework that were tracked by https://github.com/spring-projects/spring-framework/issues/22420. I'm not sure if we need a change in Framework or if Boot needs a fallback when the factory method isn't available.

[wilkinsona]

@jhoeller could you guide us here please?

[jhoeller]

@philwebb since the initial refactoring came from your side, are you aware of any gaps there? I'm not quite aware what kind of factory methods Boot would have found that we're still not exposing there...

[wilkinsona]

@jhoeller I don't think this is a result of the initial refactoring as Framework behaves the same way in 5.1 and 5.2. It's a regression in Boot as, in Boot 2.2, we're leaning more heavily on Framework and are now being affected by the difference in behaviour when caching is and is not enabled.

factoryMethodToIntrospect is set on the ConfigurationClassBeanDefinition due to a call that's made to beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false) when invoking bean factory post-processors. With caching enabled, this merged bean definition is held in the bean factory's mergedBeanDefinitions map. It's then available when making a subsequent call to getResolvedFactoryMethod(). When caching is disabled, the merged bean definition on which factoryMethodToIntrospect is set is not held in the mergedBeanDefinitions map so the information is lost. When a new merged bean definition is subsequently retrieved via a call to getMergedBeanDefinition, there's no logic to set factoryMethodToIntrospect so it's null.

Having investigated further and written up the above, I'm now of the opinion that this is a bug in Framework. getResolvedFactoryMethod() only works reliably due to a side-effect of getBeanNamesForType(). When caching is disabled, that side-effect is too short-lived to be useful. We could work around this in Boot by falling back to the old logic when getResolvedFactoryMethod() is null, but that would be a point-solution to what feels like a general problem.

[wilkinsona]

I've opened https://github.com/spring-projects/spring-framework/issues/23795 so that we can hopefully revert the main code changes in https://github.com/spring-projects/spring-boot/commit/b240c810a810c873e84d058614b5d0174591cff9 in the future.