Re: [RFC/PATCH] Add multiple workdir support to branch/checkout

From: Nguyen Thai Ngoc Duy <pclouds@gmail.com>
Date: Oct 5, 2011, 04:02 UTC
Message-ID: <CACsJy8AqYq+YF+rvUp=BBeFUAtUz783iF2jbUp3fO58yLp9ptQ@mail.gmail.com>
In-Reply-To: <1317786204-57335-1-git-send-email-jaysoffian@gmail.com>

On Wed, Oct 5, 2011 at 2:43 PM, Jay Soffian <jaysoffian@gmail.com> wrote:

Show 14 quoted lines

> When using 'git new-workdir', there is no safety mechanism to prevent the
> same branch from being checked out twice, nor to prevent a checked out
> branch from being deleted.
>
> By teaching 'checkout' to record the workdir path using
> 'branch.<name>.checkout' when switching branches, we can easily check if a
> branch is already checked out in another workdir before switching to that
> branch. Similarly, we can now add a check before deleting a branch.
>
> Allow 'checkout -f' to force the checkout and issue a warning
> instead of an error.
>
> Guard this behavior behind 'core.recordCheckouts', which we will
> teach 'git new-workdir' to set in a followup commit.

I've wanted to to something like this, but you beat me to it ;)

Could you please consider a more generic approach? What I have in mind is a mechanism to "lock" a branch, so that only commands that have the key can update it.

So instead of branch.<name>.checkout, I would have something like branch.<name>.locked = <key>, where <key> is just a string. Only commands that provide the matching <key> are allowed to update the branch. In checkout case, <key> could be "checkout: worktree".

This approach addresses more cases than just multiple workdir. We could relax restrictions on pushing to a non-bare repository: we only disallow pushing to locked branches. We can also use this to prevent users from checking out another branch (by locking HEAD) while in the middle of interactive rebase/bisect/...

-- 
Duy