Re: Regression: submodule worktrees can clobber core.worktree config

From: Duy Nguyen <pclouds@gmail.com>
Date: Jan 8, 2019, 23:22 UTC
Message-ID: <CACsJy8Cvc8v_4OEmpgKPWSO5csV6jRya7mnSQjEs4mMhHRq4AQ@mail.gmail.com>
In-Reply-To: <CAG0vfyQeA3Hm7AsYgYtP4v-Yg0=rKXW0YYfg_emAwEscZha4VA@mail.gmail.com>

On Wed, Jan 9, 2019 at 5:56 AM Tomasz Śniatowski <tsniatowski@vewd.com> wrote:

Show 24 quoted lines

>
> After upgrading to 2.20.1 I noticed in some submodule+worktree scenarios git
> will break the submodule configuration. Reproducible with:
>     git init a && (cd a; touch a; git add a; git commit -ma)
>     git init b && (cd b; git submodule add ../a; git commit -mb)
>     git -C b worktree add ../b2
>     git -C b/a worktree add ../../b2/a
>     git -C b status
>     git -C b2 submodule update
>     git -C b status
>
> The submodule update in the _worktree_ puts an invalid core.worktree value in
> the _original_ repository submodule config (b/.git/modules/a/config), causing
> the last git status to error out with:
>     fatal: cannot chdir to '../../../../../../b2/a': No such file or directory
>     fatal: 'git status --porcelain=2' failed in submodule a
>
> Looking at the config file itself, the submodule update operation applies the
> following change (the new path is invalid):
>     -       worktree = ../../../a
>     +       worktree = ../../../../../../b2/a
>
> This worked fine on 2.19.2 (no config change, no error), and was useful to have
> a worktree with (large) submodules that are also worktrees.

This scenario is not supported (or at least known to be broken in theory) so I wouldn't call this a regression even if it happens to work on 2.19.2 for some reason.

The good news is, I have something that should make it work reliably. But I don't know if it will make it to 2.21 or not.

Show 6 quoted lines

> Bisects down to:
> 74d4731da1 submodule--helper: replace connect-gitdir-workingtree by
> ensure-core-worktree
>
> --
> Tomasz Śniatowski

-- 
Duy