Last modified: 2013-08-26 09:43:55 UTC
diff=prev of first revision of a page acts funny: it claims there is "No difference" between the null and the first version of a page. It acts this way since I458fb688. Example: https://pl.wikipedia.org/w/index.php?title=Wikipedia:Powiadomienia/Podzi%C4%99kowania&oldid=37320666&diff=prev&uselang=en It should either show a diff of full page contents against a blank string, or show blank space with no additional message. Such "diffs" are normally not accessible from the interface, but the Thanks extension can link to them if a user is thanked for such edit.
A diff link between the current version as oldid and diff=next is showing the one version on both side and the "no difference" in the middle, that is also not a behaviour. The empty string came from a "Short-circuit" where the oldRev is checked against false (and if the revids between old and new the same). No idea at the moment how to handle this rare case.
