Re: [git-users] Problem using detached worktrees with commands implemented in scripts

From: Philip Oakley <philipoakley@iee.org>
Date: Oct 16, 2013, 22:39 UTC
Message-ID: <29AA597BEBC146B09E8B370949EC2CE9@PhilipOakley>
In-Reply-To: <xmqqeh7k51vg.fsf@gitster.dls.corp.google.com>

From: "Junio C Hamano" <gitster@pobox.com>

Show 8 quoted lines

> worley@alum.mit.edu (Dale R. Worley) writes:
>
>> In general, Git commands on a repository with a detached worktree can
>> be executed by cd'ing into the directory containing the .git
>> directory, ...
>
> Eh?  News to me; it might happened to have appeared to work by
> accident, but that is not by design.

I think it is this part in Dale's original email

"However, this approach does not work with "git filter-branch", which objects with "You need to run this command from the toplevel of the working tree."

that is the problem Dale has seen. IIRC there are a few commands that do require to be run from the toplevel ('git bisect' I think is another), and the detection process for 'toplevel' may not work properly when in a separated work-tree environment.

Perhaps something to consider.

Philip

Show 23 quoted lines

>
> IIRC, the intended use pattern (i.e. the change that introduced
> GIT_DIR and GIT_WORK_TREE environment variables was designed to
> support) for such a working tree is to:
>
> - export GIT_DIR that points at the correct .git directory;
>
> - export GIT_WORK_TREE that points at the correct top-level of such
>   a working tree; and then
>
> - run the commands anywhere in the working tree, as if you did not
>   export these two environment variables and instead had the .git
>   directory at the usual place in the working tree.
>
> It _is_ possible that we may have broken this canonical use pattern
> over time with more recent updates; I do not think we have extensive
> test coverage for "detached worktree" use case in the first place.
>
>> Does anyone have any feedback on this?
>
> Not exporting GIT_DIR variable in sh-setup was done not by accident
> but as a very deliberate design choice, IIRC.
> --