"git gc" removes ".git/refs/heads/master".

Hi,

maybe I found a bug in git. When I execute "git gc" in my local repository, git removes the file ".git/refs/heads/master". Is this an intended behavior (but why?) or is that a bug?

Some commands to reproduce:
~ $ mkdir tmp; cd tmp
~/tmp $ git init
Initialized empty Git repository in /home/myuser/tmp/.git/
~/tmp $ echo "content" > a
~/tmp $ git add .
~/tmp $ git commit -a -m "first commit"
Created initial commit 0b67f33: first commit
 1 files changed, 1 insertions(+), 0 deletions(-)
 create mode 100644 a
~/tmp $ cat .git/refs/heads/master
0b67f33fff4152a912fdbe8819480b8fc1f2e990
~/tmp $ git gc
Counting objects: 3, done.
Writing objects: 100% (3/3), done.
Total 3 (delta 0), reused 0 (delta 0)
~/tmp $ cat .git/refs/heads/master
cat: .git/refs/heads/master: No such file or directory
~/tmp $ cat .git/HEAD
ref: refs/heads/master
~/tmp $ 

I tested this with git v1.6.0.6, v1.6.1.1 and the current master (a34a9dbb..).

Best regards,

Bernd Lommerzheim