I know that it isn't normally safe to modify a commit from a pre-commit hook in Subversion because SVN clients will not see the version that has been committed, and will cache the wrong thing, but I'd like to clean the code from a versioning-naïve WebDAV client that won't keep a local cached copy. The idea is that when I look at the repository with an SVN client, the diffs are clean.

The client, by the way is MS Word, using 2003 XML format files. We're already using this format in a WebDAV system, but we'd like to add a versioning capability for expert users.

Everywhere I look for documentation on how to modify the code in a pre-commit hook, I get the answer "Don't do this", not the answer "Here's how to do this, but it's reccomeded you don't", so I can't even easily try it to see if it's going to cause me problems.