Dependency relationships created by AbstractDependsOnBeanFactoryPostProcessors cannot be overridden

[jwenting]

When upgrading to Spring Boot 2.1.8-RELEASE from 2.1.7-RELEASE we now get a BeanCreationException that didn't happen before (no code was changed, only the Spring Boot version number in the pom file).

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'baseEntityManager' defined in class path resource [xxxxxx/config/DatabaseContext.class]: Circular depends-on relationship between 'baseEntityManager' and 'delayedFlywayInitializer'
 	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
 	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
 	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:307)
 	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
 	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:307)
 	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
 	at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1105)
 	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867)
 	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549)
 	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141)
 	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:744)
 	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:391)
 	at org.springframework.boot.SpringApplication.run(SpringApplication.java:312)
 	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215)
 	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1204)

The bean definitions (in separate @Configuration annotated classes) are as follows:

    @Bean
    @Primary
    public LocalContainerEntityManagerFactoryBean baseEntityManager() {
        return EntityManagerFactoryBuilder.buildEntityManagerFactory(dataSource(), "xxxxxx.config.MySQLCustomDialect",
                "nl.triopsys.aangetekendmailen.domain", JSR310_PACKAGE);
    }

    @Bean
    @DependsOn("baseEntityManager")
    FlywayMigrationInitializer delayedFlywayInitializer(Flyway flyway) {
        return new FlywayMigrationInitializer(flyway, null);
    }

Again, in Spring Boot 2.1.7 (and earlier, this code was originally written against Spring Boot 1.3 and has been working in production for several years) this works as expected, the delayedFlywayInitializer gets created after the baseEntityManager (in order to run Flyway migrations after Hibernate is done with its schema updates).

[wilkinsona]

Thanks for the report and sorry for the inconvenience. This is an unanticipated side-effect of the fix for #18105.

We can't roll back that change without reinstating the problem that it addresses so I'm not yet sure what we should do. Ordering permitting, you may be able to work around the problem by using a BeanFactoryPostProcessor to set the dependsOn for the definition of your baseEntityManagerFactory bean, overwriting what Boot sets itself as of 2.1.8.

[wilkinsona]

@jwenting I can reproduce the failure you have described with Spring Boot 2.1.8, but I cannot get it to work with 2.1.7. With 2.1.7 I see the failure that was fixed by #18105:

org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'flywayInitializer' available
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:771) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1221) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:294) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:307) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1105) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:743) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:390) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:312) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1214) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1203) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
	at com.example.demo.Gh18362Application.main(Gh18362Application.java:19) [main/:na]

Can you please provide, as a zip attached to this issue, a minimal sample that fails with 2.1.8 but works with 2.1.7?

[jwenting]

Will see what I can do. It's part of a pretty large system I inherited earlier this year, who knows what all the interdepencies are under the hood...

[jwenting]

demo.zip

The demo project will fail while running Flyway under 2.1.7, while trying to create the Flyway bean under 2.1.8

[wilkinsona]

Thanks.

I can see that you have met 2.1.7's need for a bean named flywayInitializer by providing one that no-ops the migration. Unfortunately that's something of a hack that could have been taken as a signal that you were trying to do something that wasn't intended to work. Your use of both Hibernate and Flyway to update the database also doesn't follow the recommendation to use a single mechanism.

With that said, we'll see what we can do to allow you to continue with something similar to your current approach. Even if we're able to do something, you may want to consider reworking the way that you're using Flyway and Boot's auto-configuration of it. For example, providing your own Flyway bean, which will cause much of the auto-configuration to be off, may prove to be more robust.

[philwebb]

We'll add an order to our AbstractDependsOnBeanFactoryPostProcessors to allow a post processor to change things.

[jwenting]

From the commit messages in that piece of code I guess that they added the noop FlywayMigrationInitializer to force the loading of some application configuration settings from the database before the Flyway migration starts running.
That it also forces the Hibernate migration to run before Flyway was probably seen as a handy side effect more than anything.

I inherited this code that was created several years ago by people who're since gone on to other projects and/or left the company.