We just installed 2.52 on debian testing, and all edit links with symbols (including spaces) are coming up with empty text fields because the URL to the mdwn file is wrong.

For example, the existing page:

    wiki/bugs/__39__Existing_Subject__39___vs.___39__Browse__39__/

displays the bug "'Existing Subject' vs. 'Browse'".  But if we click 'Edit' on that page, we get:

    wiki/ikiwiki.cgi?page=bugs%2F'Existing%20Subject'%20vs.%20'Browse'&do=edit

.. which of course opens with a blank edit box. Note that manually typing in the correct URL:

    wiki/ikiwiki.cgi?page=bugs%2F__39__Existing_Subject__39___vs.___39__Browse__39__&do=edit

does work.