The HttpKernel component contains many classes and from time to time, someone wants to split it in several components.

It does not really brings us anything if the split components are not useable by themselves, but separating Kernel and HttpKernel is probably good to at least avoid confusing about the decoupling between bundles and the HTTP kernel itself.

Also, as things have been refactored a lot since 2.0, it's much clearer now to see where things can go in separate components. For instance, moving the Profiler/DataCollector classes to a new component is now possible as other classes do not depend on them anymore (at least in 3.0 as the TraceableEventDispatcher won't depend on the Profiler anymore).

So, here is my initial proposal for Symfony 3.0: we split the HttpKernel component into 3 separate components:

• Kernel:
  • Bundle/, Config/, DependencyInjection/, CacheClearer/, CacheWarmer/ directories
  • Kernel.php, KernelInterface.php
• Profiler:
  • Profiler/ and DataCollector/ directories
  • EventListener/ProfilerListener.php
• HttpKernel:
  • Controller/, Debug/, Event/, EventListener/, Exception/, Fragment/, HttpCache/, Log/ directories
  • Client.php, HttpKernel.php, HttpKernelInterface.php, TerminableInterface.php (to be merge with HttpKernelInterface in 3.0), UriSigner.php
  • rename KernelEvent to HttpKernelEvent and KernelEvents to HttpKernelEvents?