magit/magit — pull request #1564 by vanicat (2014-10-24 12:26:25+00:00)
Title: Check for existance of the directory in wip.

If a buffer edit a file in an non existing directory magit-inside-worktree-p fill fail with an error. As turn-on-magit-wip-save is meant to be in post-command-hook, it must not fail with an error, so we check if the directory exists.