Avoid calling other bean methods in web config

[bclozel]

This commit changes the main configuration classes for Spring MVC and
Spring WebFlux to not call other bean methods when setting up the web
infrastructure. This allows the DelegatingWebFluxConfiguration and
DelegatingWebMvcConfiguration to opt-in the lite-mode, as introduced
in gh-22461.

[bclozel]

In this PR, I'm trying to check what it would take to leverage lite-mode in the web configurations.
This changes a few public methods, but arguably those are @Bean methods and not meant to be called directly. This shows the exact dependencies required by each bean, which was not necessarily obvious in the previous version.

@jhoeller , @rstoyanchev I'd like to get your opinion on that.
Thanks!

[rstoyanchev]

The configuration support classes are documented as the "advanced option" for configuring Spring MVC or Spring WebFlux, so this will disrupt some applications using or overriding the protected methods. Fortunately those are few.

What I'm more concerned is that proxyBeanMethods is false by default. Applications extending these classes for advanced config would need to be careful not to call bean methods directly which is easy to overlook, and would be surprising. Classes may even run into that by simply upgrading to 5.2 if they already do that. It could also be an optimization that's not actually needed.

Would it make more sense to go with proxied bean methods by default and only set it to false when you're ready and willing to opt in. Boot can certainly turn off the proxying since it is in control of this configuration and guarantee it's done right.

[bclozel]

@rstoyanchev you're right - I've changed my PR accordingly. We can still add that proxyBeanMethods attribute in Spring Boot.

[sdeleuze]

👍 for that change!