Don't squash-merge if the old and new commits are the same.
lrwxrwxrwx 14 git-subtree -> git-subtree.sh
-rwxr-xr-x 11259 git-subtree.sh
-rw-r--r-- 23 shellopts.sh
-rwxr-xr-x 4326 test.sh
-rw-r--r-- 593 todo