Wikimedia Bugzilla is closed!

Transclusions can currently affect arbitrary parts of the page by producing unbalanced HTML. This makes both WYSIWYG editing and efficient updates difficult. We would thus like to move towards properly nested templates as much as possible. For existing multi-transclusion content we would like to enforce nesting as a unit, possibly using a <domparse> extension-like tag wrapping such a content block. This would still let us reuse expansions for multi-template content, which is important for large list pages like http://fr.wikipedia.org/wiki/Liste_des_premiers_pr%C3%A9fets_fran%C3%A7ais_(1800-1815).

The solution should:
* work with old and new revisions, with predictable HTML diff behavior
* support multi-transclusion/extension content reuse
* support a mix of transclusions, extension tags and page content
* work well with the VisualEditor preview