A subtle issue existed with the way we relied on isCurrentlyInCreation
to determine whether a @Bean method is being called by the container
or by user code. This worked in most cases, but in the particular
scenario laid out by SPR-8080, this approach was no longer sufficient.
This change introduces a ThreadLocal that contains the factory method
currently being invoked by the container, such that enhanced @Bean
methods can check against it to see if they are being called by the
container or not. If so, that is the cue that the user-defined @Bean
method implementation should be invoked in order to actually create
the bean for the first time. If not, then the cached instance of
the already-created bean should be looked up and returned.
See ConfigurationClassPostConstructAndAutowiringTests for
reproduction cases and more detail.
Issue: SPR-8080