Added a note on code review that this seems to be caused either by r60832 or r61101: http://www.mediawiki.org/wiki/Special:Code/MediaWiki/60832#c5762

conrad.irwin wrote:

enhancement -> major. As of r61101 the parser sets the default title every time it is run now; so it gets overwritten by parsing system messages (or indeed anything else) after the page has been parsed. Not sure the best way to fix.

ayg wrote:

Why don't we just revert r61101?

fixed in r62539

conrad.irwin wrote:

Still seems broken with $wgRestrictDisplayTitle = true; - maybe not directly related to r61101 though.

Also it seems your fix will not work if getConvLangTitle() doesn't return false (though I haven't tested)

getConvRuleTitle() will only return a non-false value (a conversion title) if -{T}- is specified. This is similar to DISPLAYTITLE.

I've provided a few more tests in r62558 that should show it works in the case that wgRestrictDisplayTitle = true. If those tests are correct, could you please re-close the bug? Otherwise, let me know what the problem is.

ayg wrote:

Something seems wrong on preview -- entering {{DISPLAYTITLE:main Page}} on [[Main Page]] and previewing gives "Editing" as the page title. It seems to work on actual page views.

after r61101, preview shows just "Main Page" with no "Editting " prefix. Tracking it down...

conrad.irwin wrote:

One last thing, shouldn't the parser tests showtitle show the original when it has not been overridden (at the moment it is blank)? Thanks for dealing with this.

fixed in r62577