This bug is probably related or the same as T127734 (cause: 155d555b83eca6403e07d2094b074a8ed2f301ae) though I do not know how to do such an elaborate error analysis.
There is a wiki accessible with the following logic:
"http://example.com/wiki/Main_Page"
When I edit I have:
"http://example.com/w/index.php?title=Main_Page&action=edit"
To get this magic running I have the following RewriteRules:
RewriteEngine On RewriteRule ^/?wiki(/.*)?$ %{DOCUMENT_ROOT}/w/index.php [L] RewriteRule ^/?$ %{DOCUMENT_ROOT}/w/index.php [L]
And in "LocalSettings.php":
$wgScriptPath = "/w"; $wgScriptExtension = ".php"; $wgArticlePath = "/wiki/$1"; $wgUsePathInfo = true; // true or false does not make a difference
Everything is cool until I dare to try accessing a page containing a special character, e.g. "http://example.com/wiki/So_ein_Ärger" and end up in an indefinite redirect loop (Fx, Ch, O, and Web/Api). Same happens to special pages containing umlauts.
This wiki is a MW 1.26.2.
Steps taken to mitigate: Downgrade wiki to MW 1.25.5 and everything works. I guess it will be cool to be able to use MW 1.26+. I think it will be important to get a fix into MW 1.27 LTS.