Changing tag from open-close to open-body-close

[Juergen Donnerstag]

wicket 1458 is about wicket not performing completely well if tags are
changed from open-close to open-body-close, e.g. like this

                        protected void onComponentTag(ComponentTag tag)
                        {
                                if (tag.isOpenClose())
                                {
                                        tag.setType(XmlTag.OPEN);
                                }
                                super.onComponentTag(tag);
                        }

what happens is that though the original tag is an open-close, and
thus doesn't have a body, renderComponentTagBody() gets called (it
tests the modified tag not the original one). We could fix that in
Component.renderComponent() but obviously some components e.g. Border
are relying on that behavior. I would therefor suggest to make the
following change to MarkupContainer.renderComponentTagBody().

        protected final void renderComponentTagBody(final MarkupStream 
markupStream,
                final ComponentTag openTag)
        {
                if ((markupStream != null) && (markupStream.getCurrentIndex() > 
0))
                {
                        // If the original tag has been changed from open-close 
to open-body-close,
                        // than historically renderComponentTagBody gets 
called, but actually
                        // it shouldn't do anything since there is no body for 
that tag.
                        ComponentTag origOpenTag =
(ComponentTag)markupStream.get(markupStream.getCurrentIndex() - 1);
                        if (origOpenTag.isOpenClose())
                        {
                                return;
                        }
                }

                .....
       }

It works well for all our test cases but I wonder whether this change
should go in 1.3.3 (to be released this week) without a lot of testing
from people using trunk. The change looks straight forward, but you
never know, especially since this is at the very core of rendering.

Juergen