Wikimedia Bugzilla is closed!

(see bug #10024 for further details)

Summary:

media-links are broken when you copy&paste the file name from a (certain) link to that file, probably due to the fact that there is an invisible character in the copy buffer. This character cannot be seen in the editig area, but, nonetheless, it is there and it is obviously being evaluated by the mediawiki software when creating a link from the [[media:filename|Download]] tag. 

Steps to reproduce:

1. Upload a file to mediawiki (say, "Test.pdf").
2. Navigate to the "file list" page (using the german version, so I'm not sure whether this is really called "file list" in the english mediawiki).
3. Click on the "description" link next to the "Test.pdf" link.
4. Now you are on the description page for Test.pdf. Mark the "Test.pdf" string from the link underneath the Acrobat logo and copy it (Ctrl+C).
5. Go to some arbitrary wiki-page, edit it and create the link [[media:Test.pdf|Download]]. Don't type the name of the file but paste it (Ctrl+V) right to the media: string.
6. Save the page and wonder why the link you just created is red and not blue (and is broken).
7. Return to the page editor, position your cursor between the "f" and the pipe "|" in the link and hit backspace. You will notice that the "f" is still there, because you just deleted some invisible character that was right beside the "f".
8. Save the page and be glad that the link now works!

This happened to me several times and it was really hard to solve, as there is no indication for the existance of that disturbing character. I suggest to ignore any invisible characters when parsing [[link]] strings.