Checked it for you: To /tmp/foo1/ ! [rejected] ddd -> ddd (already exists) error: failed to push some refs to '/tmp/foo1/' hint: Update

Checked it for you: To /tmp/foo1/ ! [rejected] ddd -> ddd (already exists) error: failed to push some refs to '/tmp/foo1/' hint: Updates were rejected because the tag already exists in the remote. I think any ref is 'mutable' by these standards, and any hash is immutable (that's the entire point of a hash).