On Fri, Dec 14, 2018 at 7:50 AM Jacob Keller <jacob.kel...@gmail.com> wrote: > > On Thu, Dec 13, 2018 at 1:16 PM Mike Rappazzo <rappa...@gmail.com> wrote: > > > > On Thu, Dec 13, 2018 at 3:48 PM Stefan Beller <sbel...@google.com> wrote: > > > > > > > > The current situation is definitely a problem. If I am in a worktree, > > > > > using "head" should be the same as "HEAD". > > > > > > By any chance, is your file system case insensitive? > > > That is usually the source of confusion for these discussions. > > > > This behavior is the same for MacOS (High Sierra) and Windows 7. I > > assume other derivatives of those act the same. > > > > On CentOS "head" is an ambiguous ref. If Windows and Mac resulted in > > an ambiguous ref, that would also be OK, but as it is now, they return > > the result of "HEAD" on the primary worktree. > > > > Because refs are *not* case sensitive, and we know that "HEAD" should > be per-worktree, it gets checked in the per-worktree refs section. But > lowercase head is known to not be a per-worktree ref, so we then ask > the main worktree about head. Since you happen to be on a case > insensitive file system, it then finds refs/HEAD in the main refs > worktree, and returns that. > > I don't understand why the CentOS shows it as ambiguous, unless you > actually happen to have a ref named head. (possibly a branch?)
I think it's just our default answer when we can't decide $ git rev-parse head head fatal: ambiguous argument 'head': unknown revision or path not in the working tree. Use '--' to separate paths from revisions, like this: 'git <command> [<revision>...] -- [<file>...]' $ git rev-parse head -- fatal: bad revision 'head' > I suspect we could improve things by attempting to figure out if our > file system is case insensitive and warn users. However, I recall > patches which tried this, and no suitable method was found. Partly > because it's not just "case" that is the only problem. There might be > things like unicode characters which don't get properly encoded, etc. > > The best solution would be to get a non-filesystem backed ref storage > working that could be used in place of the filesystem. Even with a new ref storage, I'm pretty sure pseudo refs like HEAD, FETCH_HEAD... will forever be backed by filesystem. HEAD for example is part of the repository signature and must exist as a file. We could also lookup pseudo refs with readdir() instead of lstat(). On case-preserving-and-insensitive filesystems, we can reject "head" this way. But that comes with a high cost. -- Duy
