fd42a65c6c
Prior to this change, an instance of ConfigurationClassPostProcessor would throw IllegalStateException if its postProcessBeanDefinitionRegistry method were called more than once. This check is important to ensure that @Configuration classes are not proxied by CGLIB multiple times, and works for most normal use cases. However, if the same CCPP instance is used to process multiple registries/factories/contexts, this check creates a false negative because it does not distinguish between invocations of postProcessBeanDefinitionRegistry across different registries. A use case for this, though admittedly uncommon, would be creating a CCPP instance and registering it via ConfigurableApplicationContext#addBeanDefinitionPostProcessor against several ApplicationContexts. In such a case, the same CCPP instance will post-process multiple different registry instances, and throw the above mentioned exception. With this change, CCPP now performs lightweight tracking of the registries/beanFactories that it has already processed by recording the identity hashcodes of these objects. This is only slightly more complex than the previous boolean-based 'already processed' flags, and prevents this issue (however rare it may be) from occurring. Issue: SPR-8527