* The helper module adds a new _helper_serial property onto AbstractController subclasses
* When #helper is used to add helpers to a class, the serial number is updated
* An ActionView subclass is created and cached based on this serial number.
* That subclass includes the helper module from the controller
* Subsequent requests using the same controller with the same serial will result in
reusing that subclass, rather than being forced to take an action (like include
or extend) that will result in a global method cache flush on MRI and a flush
of the entire AV class' cache on JRuby.
* For now, this optimization is not applied to the RJS helpers, which results in
a global method cache flush in MRI and a flush of the JavaScriptGenerator class in
JRuby only when using RJS.
* Since the effects are limited to using RJS, and would only affect JavaScriptGenerator
in JRuby (as opposed to the entire view object), it seems worthwhile to apply this
now.
* This resulted in a significant performance improvement. I will have benchmarks
in the next day or two that show the performance impact of the last several
commits.
* There is a small chance this could break existing code (although I'm not sure how).
If that happens, please report it immediately.
* It is not possible to always pre-determine the layout before going to ActionView.
This was *already* broken for render :partial => @object, :layout => true. This is
now handled by overriding render_to_body in layouts.rb and manually injecting the
partial's response. This needs to be done in ActionController since ActionController
knows enough to get _layout_for_option. There is probably a better abstraction here.
* As a result, all partial rendering can correctly restrict their layouts to the mime
type of the rendered partial. This could have previously caused a bug in some edge cases.
* If other layout-like options are added, they might need to add special code for the
case of render :partial. We should try to think of an alternate solution, if possible,
but this works for the cases we know of now.
* TODO: Review ActionController calling render_template for certain partials.
Might we be able to save logic by always delegating to AV's render_partial?
* _render_single_template, which renders a template without layout
* _render_partial_unknown_type, which renders a partial of unknown type
(the entry method for most partial rendering; supports strings, objects, and collections)
* _render_partial_object, which renders a partial for a single object.
* extracted _render_partial_path so it can be used to render the spacer without going
through the public render :partial
* rename _render_partial to _render_partial_unknown_type to reflect that for this call,
we don't know the type.
* Merge _render_partial_with_block and _render_partial_with_layout to _render_partial
* TODO: Check to see if any more logic can be shared
* TODO: See about streamlining block path so we can get rid of @_proc_for_layout
* Remove @exempt_from_layout as it is no longer needed
* remove no longer used _array_like_objects
* _render_content_with_layout renamed to _render_content since layout it optional
* remove check for optional layout before _render_content
