The patch series results in a change in output as specified below. Only
few cases
have been shown here to keep it short. The output for other cases are
similar.
$ git branch
* master
foo
bar
Before patch,
$ # Trying to rename non-existent branch
$ git branch -m hypothet no_such_branch
error: refname refs/heads/hypothet not found
fatal: Branch rename failed
$ # Trying to rename non-existent branch into existing one
$ git branch -m hypothet master
error: refname refs/heads/hypothet not found
fatal: Branch rename failed
$ # Trying to force update current branch
$ git branch -M foo master
fatal: Cannot force update the current branch.
$ # Trying to force rename an in-existent branch with an invalid name
$ git branch -M hypothet ?123
fatal: '?123' is not a valid branch name.
After patch,
$ # Trying to rename non-existent branch
$ git branch -m hypothet no_such_branch
fatal: branch 'hypothet' doesn't exist
$ # Trying to rename non-existent branch into existing one
$ git branch -m hypothet master
fatal: branch 'hypothet' doesn't exist, and branch 'master' already exists
$ # Trying to force update current branch
$ git branch -M foo master
fatal: cannot force update the current branch
$ # Trying to force rename an in-existent branch with an invalid name
$ git branch -M hypothet ?123
fatal: branch 'hypothet' doesn't exist, and branch name '?123' is invalid
