Beans created with BeanRegistrar or GenericApplicationContext in initializer do not honor default allow-bean-definition-overriding setting

[hajdamak]

Although default setting in Spring Boot for allowing bean overriding (spring.main.allow-bean-definition-overriding) is false, beans created with BeanRegistrar or GenericApplicationContext in initializer do no honor it.
So following will not fail:

fun main(args: Array<String>) {
    SpringApplicationBuilder(ExampleApp::class.java)
        .run {
            initializers(
                ApplicationContextInitializer<GenericApplicationContext> {
                    it.register(ExampleRegistrar())
                }
            )
            build()
        }
        .run()
}

class ExampleApp

class ExampleRegistrar :
    BeanRegistrarDsl({
        registerBean("example") { ExampleBean() }
        registerBean("example") { ExampleBean() }
    })

class ExampleBean

same with beans registered using GenericApplicationContext, for example:

ApplicationContextInitializer<GenericApplicationContext> {
    it.registerBean("example", ExampleBean::class.java, Supplier { ExampleBean() })
    it.registerBean("example", ExampleBean::class.java, Supplier { ExampleBean() })
}

Setting setAllowBeanDefinitionOverriding to false in GenericApplicationContext will cause it to fail:

ApplicationContextInitializer<GenericApplicationContext> {
    it.setAllowBeanDefinitionOverriding(false)
    ...
}

It will also fail when importing ExampleRegistrar using @Import annotation instead of register function in GenericApplicationContext:

@Import(ExampleRegistrar::class)
class ExampleApp

Spring Boot 4.0.3

[kwondh5217]

Hi team, I took a quick look at this issue and noticed that DefaultListableBeanFactory#isAllowBeanDefinitionOverriding() returns true when allowBeanDefinitionOverriding is null (its initial value). Just wanted to check, is this intended behavior?

[hajdamak]

There is also most likely related problem with circular dependency reporting as described in #50045