Several people have reported seeing a very strange error message from Subversion, usually when they're trying to submit, that looks like the following:

svn: MKCOL of '/670/!svn/wrk/1fbb671d-fe29-0410-8551-f45a352d06c5/lee1tim-leonsico/turnin/Project5':
405 Method Not Allowed (http://svn.barzilay.org)
      

Since this error message gives you almost no information about what's going on, people immediately email me in a panic when they see this. Fortunately, it's usually pretty easy to get around this problem.

I've seen this error message arise in two cases. First, you will see this error if you try to add a directory to the repository that already exists in the repository. In this case, here's how to proceed:

1. Move your copy of the directory out of the way.

2. Use svn revert to back out of the uncommitted svn add or svn mkdir. Specify the name of the directory as an argument to the revert command so you don't delete any other changes by mistake.

3. Use svn update to get the repository's copy of the new directory, then merge the contents of your copy in by hand.

Second, you will see this error as you're following the submission instructions but create your <TMP> directory in your existing working copy. To fix this, just delete the temp directory and try again in another location.

The next time you see this error message, please try these steps to fix the problem before you email me.

And, since this is a course about constructing robust software, there's something else we can learn from this. This error is a perfect example of why you must think about your software's error messages, and whether or not they'll be helpful to your users—who almost certainly don't know the software as well as you do.