Re: [PATCH] worktree add: be tolerant of corrupt worktrees

[Shaheed Haque <shaheedhaque@gmail.com>]

On Sat, 18 May 2019 at 12:50, Duy Nguyen <pclouds@gmail.com> wrote:
>
> On Fri, May 17, 2019 at 2:46 PM Eric Sunshine <sunshine@sunshineco.com> wrote:
> >
> > On Mon, May 13, 2019 at 6:50 AM Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
> > > find_worktree() can die() unexpectedly because it uses real_path()
> > > instead of the gentler version. When it's used in 'git worktree add' [1]
> > > and there's a bad worktree, this die() could prevent people from adding
> > > new worktrees.
> >
> > This is good to know because, to fix [1], I think we'll want to add a
> > new function[2] akin to find_worktree(), but without magic suffix
> > matching (that is, just literal absolute path comparison).
>
> Yeah. find_worktree() was made to handle command line options from
> worktree's move/remove, it's probably a bit too magical for this case.
>
> I still want to store relative path in "gitdir" files at some point,
> which would complicate the last "absolute path comparison" part a bit.
> But it should be manageable.
>
> > [1]: https://public-inbox.org/git/0308570E-AAA3-43B8-A592-F4DA9760DBED@synopsys.com/
> > [2]: https://public-inbox.org/git/CAPig+cQh8hxeoVjLHDKhAcZVQPpPT5v0AUY8gsL9=qfJ7z-L2A@mail.gmail.com/
> >
> > > The "bad" condition to trigger this is when a parent of the worktree's
> > > location is deleted. Then real_path() will complain.
> > >
> > > Use the other version so that bad worktrees won't affect 'worktree
> > > add'. The bad ones will eventually be pruned, we just have to tolerate
> > > them for a bit.
> >
> > The patch itself makes sense, though, as Shaheed noted in his
> > response, pruning seems to get short-circuited somehow under this
> > situation; perhaps that needs its own fix, but certainly shouldn't
> > hold up this fix.
>
> I might have missed that detail. Thanks for pointing out. Will get another look.

On the off-chance this is not obvious to you experts, 'worktree
remove' also hits this issue, as you can see from this little example
I just caught:

$ git worktree remove --force /tmp/tmp56t59s2k/git_worktree.pa44kgs0
fatal: Invalid path '/tmp/tmpy4f98pwj': No such file or directory
$ mkdir /tmp/tmpy4f98pwj
$ git worktree remove --force /tmp/tmp56t59s2k/git_worktree.pa44kgs0
fatal: Invalid path '/tmp/tmp_q3p2mon': No such file or directory
$ mkdir /tmp/tmp_q3p2mon
...
several more suppressed
...
$ git worktree remove --force /tmp/tmp56t59s2k/git_worktree.pa44kgs0
fatal: '/tmp/tmp56t59s2k/git_worktree.pa44kgs0' is not a working tree

Thanks, Shaheed

>
> --
> Duy