Is this Bean declaration correct?

[ilxqx]

Have a look at the bean named po in FunctionConfiguration.class

@Bean
    public BeanFactoryPostProcessor po(Environment environment) {
        return new FunctionConfiguration.PollableSourceRegistrar(environment);
    }

I think this bean causes the instantiation of all beans in BeanFactory before invoking or registering BeanPostProcessor
Describe the issue
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. Clone the demo code from https://github.com/Venus-WXP/spring-cloud-stream-bug-demo
2. Download deps and Run application
3. It is expected if you got the following error:

2022-05-24 21:15:33.012  WARN 47231 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'po' defined in class path resource [org/springframework/cloud/stream/function/FunctionConfiguration.class]: Unsatisfied dependency expressed through method 'po' parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myBean': Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'concreteA1' defined in file [/Users/venus/Downloads/bean-test/target/classes/com/example/beantest/bean/ConcreteA1.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.example.beantest.bean.ConcreteA1]: No default constructor found; nested exception is java.lang.NoSuchMethodException: com.example.beantest.bean.ConcreteA1.<init>()
2022-05-24 21:15:33.021  INFO 47231 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2022-05-24 21:15:33.030 ERROR 47231 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'po' defined in class path resource [org/springframework/cloud/stream/function/FunctionConfiguration.class]: Unsatisfied dependency expressed through method 'po' parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myBean': Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'concreteA1' defined in file [/Users/venus/Downloads/bean-test/target/classes/com/example/beantest/bean/ConcreteA1.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.example.beantest.bean.ConcreteA1]: No default constructor found; nested exception is java.lang.NoSuchMethodException: com.example.beantest.bean.ConcreteA1.<init>()
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:800) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:541) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1352) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1195) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:213) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:196) ~[spring-context-5.3.20.jar:5.3.20]
	at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:746) ~[spring-context-5.3.20.jar:5.3.20]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:564) ~[spring-context-5.3.20.jar:5.3.20]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147) ~[spring-boot-2.7.0.jar:2.7.0]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:734) ~[spring-boot-2.7.0.jar:2.7.0]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:408) ~[spring-boot-2.7.0.jar:2.7.0]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) ~[spring-boot-2.7.0.jar:2.7.0]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1306) ~[spring-boot-2.7.0.jar:2.7.0]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1295) ~[spring-boot-2.7.0.jar:2.7.0]
	at com.example.beantest.BeanTestApplication.main(BeanTestApplication.java:15) ~[classes/:na]
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myBean': Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'concreteA1' defined in file [/Users/venus/Downloads/bean-test/target/classes/com/example/beantest/bean/ConcreteA1.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.example.beantest.bean.ConcreteA1]: No default constructor found; nested exception is java.lang.NoSuchMethodException: com.example.beantest.bean.ConcreteA1.<init>()
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:800) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:229) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1372) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1222) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getSingletonFactoryBeanForTypeCheck(AbstractAutowireCapableBeanFactory.java:1027) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getTypeForFactoryBean(AbstractAutowireCapableBeanFactory.java:907) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractBeanFactory.isTypeMatch(AbstractBeanFactory.java:637) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doGetBeanNamesForType(DefaultListableBeanFactory.java:583) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:542) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.BeanFactoryUtils.beanNamesForTypeIncludingAncestors(BeanFactoryUtils.java:265) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1555) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1352) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1309) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:887) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:791) ~[spring-beans-5.3.20.jar:5.3.20]
	... 19 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'concreteA1' defined in file [/Users/venus/Downloads/bean-test/target/classes/com/example/beantest/bean/ConcreteA1.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.example.beantest.bean.ConcreteA1]: No default constructor found; nested exception is java.lang.NoSuchMethodException: com.example.beantest.bean.ConcreteA1.<init>()
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1334) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1232) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.addCandidateEntry(DefaultListableBeanFactory.java:1607) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1571) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveMultipleBeans(DefaultListableBeanFactory.java:1460) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1347) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1309) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:887) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:791) ~[spring-beans-5.3.20.jar:5.3.20]
	... 33 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.example.beantest.bean.ConcreteA1]: No default constructor found; nested exception is java.lang.NoSuchMethodException: com.example.beantest.bean.ConcreteA1.<init>()
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:83) ~[spring-beans-5.3.20.jar:5.3.20]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1326) ~[spring-beans-5.3.20.jar:5.3.20]
	... 48 common frames omitted
Caused by: java.lang.NoSuchMethodException: com.example.beantest.bean.ConcreteA1.<init>()
	at java.base/java.lang.Class.getConstructor0(Class.java:3349) ~[na:na]
	at java.base/java.lang.Class.getDeclaredConstructor(Class.java:2553) ~[na:na]
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:78) ~[spring-beans-5.3.20.jar:5.3.20]
	... 49 common frames omitted

4. Try removing the following dependencies from the POM.xml and running the application again

<dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-bus-amqp</artifactId>
            <version>3.0.3</version>
        </dependency>

5. You can see the application starts up normally and access the following address in your browser: http://localhost:8082 and you can see the following output in Terminal in your IDE:

I am the concrete A1
I am the concrete A2

Version of the framework
SpringBoot 2.7.0
spring-cloud-starter-bus-amqp 3.0.3
spring-cloud-stream 3.1.3
Expected behavior
The application mentioned above could be started successfully wheather or not the spring-cloud-starter-bus-amqp dep exists
Guess
The bean named po in FunctionConfiguration.class causes the bean definition in the BeanFactory to be instantiated early, before the BeanPostProcessor is invoked/registered in AbstractApplicationContext.refresh()#567 method, meanwhile the bean is not enhanced, and it is not possible to determine the bean Constructor declaring dependencies because the AutowiredAnnotationBeanPostProcessor class does not exist in BeanPostProcessorCache of AbstractAutowireCapableBeanFactory.java#1297