After upgrading my Subversion server to Ubuntu Feisty, I noticed that when committing I got the following error:
svn: MERGE request failed on '/svn/repository/trunk' svn: MERGE of '/svn/repository/trunk': 200 OK (http://svn.myserver.com)
Although the messages says that the commit failed, it has not. A simple 'svn update' will merge the changes you made to the repository to your working copy again and you're good to go.
So, what is the problem here? Are you by any chance running Trac? Did you install the post-commit hook to integrate Subversion with Trac? Right, so did I.
The problem here is that the trac-post-commit-hook script needs a few updates in order to include the proper modules. Take a look at the most recent 0.10.x version.
After updating the trac-post-commit-hook script, commits worked fine again. Such an easy fix for such a nasty problem.