Hi, Ævar Arnfjörð Bjarmason wrote: > So the reason we have this for -m is: > > commit 3f59481e33 > Author: Jonathan Nieder <jrnieder@xxxxxxxxx> > Date: Fri Nov 25 20:30:02 2011 -0600 > > branch: allow a no-op "branch -M <current-branch> HEAD" > > Overwriting the current branch with a different commit is forbidden, as it > will make the status recorded in the index and the working tree out of > sync with respect to the HEAD. There however is no reason to forbid it if > the current branch is renamed to itself, which admittedly is something > only an insane user would do, but is handy for scripts. > > 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. Thanks and hope that helps, Jonathan