I found a back related to the funktionality of the Backlinks.
Whenever I create a Link to a Page with ä,ü,ö <- german umlaut
the wiki changes the link because of the deaccentation to ae, oe, ue
this is working fine and in a manner I think it should.
But if I look at the backlinks of the page, there isn't a single Backlink
though I created the Page trough making a link to it.
An Example can be found in the local Playground
I experience the same bug (only when deaccent is >0). It is due to the implementation of backlinks by searching in page sources (deaccented page identifiers may not appear and therefore not found).
This could he a difficult thing to fix. It could possible to construct a regexp to check for accent possibilities when searching. In a quick test, constructing a regex was straightforward, but working it into DW was non-trivial.
I think the ideal solution is (as you discovered) to turn off deaccent. An alternative is to include the accented page name somewhere in the page.
Is it reasonable to make the $conf['deaccent'] default setting off (0) ?
Personally, for me deaccent=2 is one of the selling points of DokuWiki. I even find romanization more useful than backlinks in my practice (I prefer to have deaccent=2 and not to show "backlinks" button to my Russian-language wiki users).
Cannot the issue be solved by putting deaccented/romanized link names into the meta-files? And then search in meta-files and not in the pages themselves? This could also be faster... I understand this is most probably not for the upcoming release.
You could be on the right track. Its probably the deaccented or romanised (depending on settings) page name that should be added to the page index - instead of or maybe along with the unchanged name.
devel version patch sent.