Re: git worktrees must exist even if locked

[Duy Nguyen <pclouds@gmail.com>]

On Thu, May 11, 2017 at 3:24 AM, taylor, david <David.Taylor@dell.com> wrote:
> The Git documentation in describing worktrees says that one reason
> why you might want to lock a worktree is to prevent it from being pruned
> if it is on a removable media that isn't currently mounted.
>
> So, my expectation was that if the worktree is inaccessible (and locked), Git
> would pretend that there is no worktree by that name.
>
> In reality, if you have such a worktree, Git gets an error.
>
>  On local systems, /home is local to a machine; home directories are elsewhere.
> Home directories are NFS mounted; /home is not.
>
> . create a repository in /my/home/dir/my-repo.git with
>
>     git clone --bare <some arguments>
>
> . create an empty directory /home/somedir/worktree-tests
>
> . use 'git worktree add' to add /home/somedir/worktree-tests/<branch-name>
>   as a worktree on branch <branch-name>.  It gets populated with the correct
>   content.
>
> . lock it using'git worktree lock'
>
> So far, so good.  Now, go to a different computer -- one on which
> /home/somedir/worktree-tests does not exist (and therefore
> /home/somedir/worktree-tests/<branch-name> does not exist).
>
> . cd /my/home/dir/my-repo.git
>
> Now, try issuing Git commands.  Many will fail.
>
>   git fetch ==> fails:
>
>   fatal: Invalid path '/home/somedir/worktree-tests': No such file or directory
>
>   git status ==> fails -- same error as above
>   git help worktree ==> fails -- same error as above

FWIW I couldn't reproduce this. The fact that "git help" also fails
suggests this is triggered by some early setup code, which narrows
down the starting point to strbuf_realpath (that can print "Invalid
path", the other call in read-cache.c involves adding index entries
and can be ignored). But I fail to see how early setup code needs to
look at any worktree at all, especially when you issue command
standing from my-repo.git (i.e. bare repo setup, even current worktree
is ignored). An strace output, if possible, might help pinpoint the
problem.
-- 
Duy