Re: [PATCH v2] builtin/branch.c: remove useless branch_get

> branch_get sometimes returns current_branch, which can be NULL (e.g., if
> you're on a detached HEAD). Try:
> 
>   $ git branch HEAD
>   fatal: no such branch 'HEAD'
> 
>   $ git branch ''
>   fatal: no such branch ''
> 
> However, it seems weird that we'd check those cases here (and provide
> such lousy messages). And indeed, dropping that and letting us
> eventually hit create_branch() gives a much better message:
> 
>   $ git branch HEAD
>   fatal: 'HEAD' is not a valid branch name.
> 
>   $ git branch ''
>   fatal: '' is not a valid branch name.