oauth2Login DSL fails when passing a SecurityContextRepository

[marcusdacoregio]

Describe the bug

Hi team ❤ , I'm trying to set the SecurityContextRepository configured by the oauth2Login() DSL and it fails with:

Caused by: java.lang.NullPointerException: Cannot invoke "org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.setSecurityContextRepository(org.springframework.security.web.context.SecurityContextRepository)" because "this.authFilter" is null
	at org.springframework.security.config.annotation.web.configurers.AbstractAuthenticationFilterConfigurer.securityContextRepository(AbstractAuthenticationFilterConfigurer.java:149) ~[spring-security-config-6.4.2.jar:6.4.2]
	at com.dooall.oauth2loginbug.Oauth2LoginBugApplication.lambda$filterChain$0(Oauth2LoginBugApplication.java:20) ~[main/:na]
	at org.springframework.security.config.annotation.web.builders.HttpSecurity.oauth2Login(HttpSecurity.java:2857) ~[spring-security-config-6.4.2.jar:6.4.2]
	at com.dooall.oauth2loginbug.Oauth2LoginBugApplication.filterChain(Oauth2LoginBugApplication.java:19) ~[main/:na]

I couldn't find any older issue related to this. The authFilter from AbstractAuthenticationFilterConfigurer is only instantiated at the OAuth2LoginConfigurer#init method, but setSecurityContextRepository is called before init. The current workaround is to add a ObjectPostProcessor:

.addObjectPostProcessor(new ObjectPostProcessor<OAuth2LoginAuthenticationFilter>() {
	@Override
	public <O extends OAuth2LoginAuthenticationFilter> O postProcess(O filter) {
		filter.setSecurityContextRepository(new NullSecurityContextRepository());
		return filter;
	}
})

To Reproduce
Clone the sample application and run it.

Expected behavior
The DSL should accept the provided SecurityContextRepository

Sample

https://github.com/marcusdacoregio/oauth2-login-bug