Re: [PATCH/RFC] branch: add tests for new copy branch feature

>>> My understanding of that last part is that Jonathan/someone (see
>>> reported-by in that patch) had some script which was renaming
>>> branches, and it was easier for whatever reason to just make it no-op
>>> if the rename would have yielded the same result as doing nothing at
>>> all.
>>>
>>> Most likely your implementation will consist of just re-using the
>>> logic in rename_branch() (and renaming it to e.g.
>>> copy_or_rename_branch() ...) so you could just re-use the no-op
>>> behavior we use for -m, or if there's some reason not to no-op and
>>> error instead for -c we could just do that, but in any case this case
>>> of `git branch -c master master` or `git branch -c currentbranch`
>>> should be tested for.
>>
>> I may be missing some context, but notice that the above mentioned
>> commit is about -M, not -m.
>
> The context was just that that commit added a change in how -M
> interacted when clobbering the current HEAD, and that -C should have a
> test for that behavior, which the patch now submitted to the list has:
>
>     +test_expect_success 'git branch -C master master should work when master is checked out' '
>     +       git checkout master &&
>     +       git branch -C master master
>     +'