On Wed, Aug 23, 2017 at 01:13:34PM -0700, Nish Aravamudan wrote: > Hello, > > Hopefully, I've got this right -- I noticed a change in behavior in git > with Ubuntu 17.10, which recently got 2.14.1. Specifically, that when in > an orphaned branch, -M ends up moving HEAD to the new branch name, > clobbering the working tree. As far as I know, from the manpages, > orphaned branches are still supported and should work? > > I think an example will demonstrate more than words (the following are > done in LXD containers, hence the root user): > > # git --version > git version 2.14.1 > # mkdir test && cd test && git init . > Initialized empty Git repository in /root/test/.git/ > # git checkout -b a > Switched to a new branch 'a' > # touch testfile && git add testfile && git commit -m 'initial commit' > [a (root-commit) 6061193] initial commit > Committer: root <root@xxxxxxxxxxxxxxxxxxx> > 1 file changed, 0 insertions(+), 0 deletions(-) > create mode 100644 testfile > # git checkout --orphan master > Switched to a new branch 'master' > # git status > On branch master > > No commits yet > > Changes to be committed: > (use "git rm --cached <file>..." to unstage) > > new file: testfile > > # git reset --hard && git status > On branch master > > No commits yet > > nothing to commit (create/copy files and use "git add" to track) > # git branch -M a b > # git status > On branch b > Changes to be committed: > (use "git reset HEAD <file>..." to unstage) > > deleted: testfile > > This is very unexpected. I force-renamed a branch I wasn't currently > checked out to and now I'm checked out to it *and* I have staged file > removals (I think what is effectively happening is my current working > directory (empty) is being staged into the new branch, but I'm not > 100%). > > For comparision, on 17.04: > > # git --version > git version 2.11.0 > # mkdir test && cd test && git init . > Initialized empty Git repository in /root/test/.git/ > # git checkout -b a > Switched to a new branch 'a' > # touch testfile && git add testfile && git commit -m 'initial commit' > [a (root-commit) f8d0d53] initial commit > Committer: root <root@xxxxxxxxxxxxxxxxxxx> > 1 file changed, 0 insertions(+), 0 deletions(-) > create mode 100644 testfile > # git checkout --orphan master > Switched to a new branch 'master' > # git status > On branch master > > No commits yet > > Changes to be committed: > (use "git rm --cached <file>..." to unstage) > > new file: testfile > > # git reset --hard && git status > On branch master > > No commits yet > > nothing to commit (create/copy files and use "git add" to track) > # git branch -M a b > # git status > On branch master > > Initial commit > > nothing to commit (create/copy files and use "git add" to track) > > This is what I expect to see, the branch rename has no effect on HEAD. > > I haven't yet bisected this (but I can if necessary). My initial > suspicion is > https://github.com/git/git/commit/70999e9ceca47e03b8900bfb310b2f804125811e#diff-d18f86ea14e2f1e5bff391b2e54438cb > where a comparison between the oldname of the branch and HEAD was > performed before attempting to move HEAD (so that HEAD followed to the > new branch name, I believe). That change was dropped, though and perhaps > the new check in replace_each_worktree_head_symref of > > strcmp(oldref, worktrees[i]->head_ref) > > does not work for orphaned branches? I am unfamiliar with all the > details of the git internals, so please correct me if I'm wrong! > > Thanks, > Nish > > -- > Nishanth Aravamudan > Ubuntu Server > Canonical Ltd Thanks for this report. I've bisected it down to fa099d232 (worktree.c: kill parse_ref() in favor of refs_resolve_ref_unsafe(), 2017-04-24) I've CC'ed Duy, who made that commit. Kevin
