Why temp files when diffing working copy?

When I do a diff of my local modifications against base (or head, or any
other repository revision for that matter), subversion makes a copy of
my modified file in .svn/tmp and uses that for the diff.

Why does it do that? I find this very inconvenient. With CVS, I am
used to editing my modified files right in the graphical diff program
(for example to fix simple spelling errors in comments, or to revert one
of the diff chunks while keeping the others). I do this all the time,
and it's very annoying not to be able to do it in subversion.

-- 
Stefan Haller
Ableton
http://www.ableton.com/
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@subversion.tigris.org
For additional commands, e-mail: users-help@subversion.tigris.org