Bug? - Unexpected lock file error

In playing around with creating new unatached branches I came across a seemingly bogus "fatal: unable to create '.git/index.lock': File exists" error message.

Now I understand that the final merge below is a no-op at best but the resulting error message is less than intuitive.

This is in "git version 1.6.0.1.319.g9f32b.dirty" (msysgit/devel, but I doubt that makes a difference).

Comments?

# Make a couple of versions of 'a' in main repo mkdir foo cd foo git init -q touch a for i in a b c; do echo $i > a && git add a && git commit -q -m $i; done

# Make a new repo and push it into main repo (to make an unattached branch) mkdir empty cd empty git init -q git commit -q --allow-empty -m empty git push .. master:empty

# Trigger "fatal: unable to create '.git/index.lock': File exists" error cd .. git merge empty

If 'empty' has any commits then the merge happens as expected. Is this just another special case involving initial commits that I should just get over? Or is there something more substantive going on here?

- Eric