Re: "add worktree" fails with "fatal: Invalid path" error

From: Shaheed Haque <shaheedhaque@gmail.com>
Date: May 13, 2019, 12:55 UTC
Message-ID: <CAHAc2jf2Ojve=NaEshXx9qk8rtD4NHxqLEpqZq8c9t0yE4m_Qw@mail.gmail.com>
In-Reply-To: <CACsJy8C++Ds4kfs_Wc8UiVQgni-ypbyJ+0bFg1m5brt+s0Tfig@mail.gmail.com>

Hi Duy,

On Mon, 13 May 2019 at 10:21, Duy Nguyen <pclouds@gmail.com> wrote:

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>
> On Sun, May 12, 2019 at 5:14 PM Shaheed Haque <shaheedhaque@gmail.com> wrote:
> >
> > Hi,
> >
> > I'm running git v.2.20.1 on Ubuntu from a program which follows the pattern:
> >
> > ============
> > 1. create a temporary directory /tmp/tmpabc
>
> When is this directory deleted? After step 3a?

Yes. I note that I screwed up the numbering in my note - the order is ["git branch -D", "git worktree prune", delete directory].

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> > 2. in a loop:
> >     2a. create a second level of temporary directory /tmp/tmpabc/tmpworktree123
> >     2b. use "git worktree add" on the second level directory
> >     2c. do something
> > 3. cleanup
> >     3b. "git branch -D" on each basename(second level directory)
> >     3a. "git worktree prune"
> > ============
> >
> > The loop size is of the order of 8-20. In step 2b, I often get errors
> > like this (from a Bash reproducer):
> >
> > ============
> > $ git worktree add /tmp/tmpgtxug4y9/git_worktree.gBGqnfnU
> > Preparing worktree (new branch 'git_worktree.gBGqnfnU')
> > fatal: Invalid path '/tmp/tmp1q9ysvyl': No such file or directory
> > ============
> >
> > I can see that the problematic path exists in the "gitdir" file of
> > what must be an earlier worktree from an older run (the branch is
> > gone, but the tree is still there). The path appear to relate to the
> > older run's first level directory:
> >
> > ============
> > $ grep -r /tmp/tmp1q9ysvyl ../.git/worktrees/
> > ../.git/worktrees/git_worktree.frcwtjt_/gitdir:/tmp/tmp1q9ysvyl/git_worktree.frcwtjt_/.git
> > $ git worktree list
> > ...
> > /tmp/tmp1q9ysvyl/git_worktree.frcwtjt_  edde3f25 (detached HEAD)
> > ...
> > $ git branch | grep frcwtjt_
> > <no matches>
> > ============
>
> Yeah I think I know where that "Invalid path" comes from and it should
> not be there (at least it should not be a fatal error). I'll need to
> reproduce this first. But I'm certain you've given me enough
> information to do so.
>
> > NOTE: I've not yet had to try deleting the worktree, since "add
> > worktree" does appear to work some of the time, so I am able to limp
> > along.
>
> It's probably best to stay clean and delete things after you're done.
> At least you should be able to avoid this problem this way until it's
> fixed.

Ack.

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> > I have these questions:
> >
> > 1. There is no branch or first level directory, but "git prune" has
> > not deleted the worktree, is this expected?
>
> I assume you meant "git worktree prune", not "git prune". See
> gc.worktreePruneExpire. Dead worktree info stays for a while until
> it's deleted, so that you can recover stuff if you need to.

Yes, sorry for typo.

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> > 2. Is there something wrong with the sequence of steps I am following?
>
> Nope. I mean, you could try "git worktree remove" to be on the safe
> side. But it should work even without that. To me this looks very much
> like a bug.

The original code used the more obvious "git worktree remove" rather than "git worktree prune" but I switched partly because remove seemed slow (I cannot now quantify what caused me to think that), and partly because I was having other issues which, I now realise, you probably addressed in your recent "stat versus mkdir race" change.

BTW: I *love* worktrees. I have used/wrapped/developed multiple source
control systems over the years, and IMHO, this is one of the killer
features of git.

Thanks, Shaheed

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> > Thanks, Shaheed
> >
> > P.S. I have an strace of a failing worktree add if needed.
> --
> Duy