FacesContext EL variable incorrectly references previous instance in web.xml error page

[BalusC]

https://github.com/omnifaces/showcase/issues/19 with Mojarra 4.0.0.

Basically:

1. have a Facelet as general error page registered in web.xml
2. in a test Facelet, let the view reference #{facesContext} during postback and let the bean action method throw an exception on a non-ajax request (this will internally abort the request, release the faces context, and the server will trigger response.sendError() which in turn creates new faces context if the error page happens to be a Facelet)
3. in the error page source, try to reference #{facesContext.something}

Expected behavior: it works fine. Actual behavior: it throws ISE in assertNotReleased() because #{facesContext} EL variable is still referencing the previous instance from before response.sendError()

It worked fine in Mojarra 2.3 / 3.0.

[BalusC]

It worked fine as #{facesContext} EL in previous Mojarra versions because ImplicitObjectELResolver took care of it. However the CDI producer still gave the wrong instance via @Inject FacesContext in beans. After removal of ImplicitObjectELResolver and relying solely on CDI produder it went wrong in #{facesContext} EL as well.

I implemented sort of work around by manually destroying the CDI-produced instance in FacesContext#release().

The correct solution would have been to introduce a custom CDI scope like FacesContextScope but that involves a bit more work.