This is kind of similar to http://stackoverflow.com/questions/1601021/subversion-merge-has-different-repository-root-than - but appears to be a very different cause (especially as the answer for that question didn't resolve my problem).
A while back, we swapped out the server where our SVN repositories are located - but we've been using an alias so that the old server name points to the new server. I've been getting in the habit where I will use the new server name wherever I checkout new working copies - but we having made changes to most of the current working copies as they are live websites.
Until now, this hasn't been a problem - except that this morning I merged in some changes from my development branch to a working copy I have of the release version and I got the message "file has different repository root" and the merge stops dead.
I know this is because I'm using the new server name when the development branch was updated via the old server name - but is there a simple way to fix this?
Or if not a simple way - is there a well-documented way to fix this?