Re: Running 'git worktree add' in 'pre-commit' hook

From: Duy Nguyen <pclouds@gmail.com>
Date: May 16, 2019, 11:25 UTC
Message-ID: <CACsJy8DnkjuZD-9pbhAsFo16jHKt8U831LLxb3-nCQP5_FOmtA@mail.gmail.com>
In-Reply-To: <CAJFQqN+Z9eX6onaj8vVSqpvf-nOC7-Y0Un4NLUie6x6bGfmvZA@mail.gmail.com>

On Tue, May 14, 2019 at 9:53 PM Cosmin Polifronie <oppturbv@gmail.com> wrote:

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>
> Hello! I am trying to run 'git worktree add <path> HEAD' in the
> 'pre-commit' hook, more specifically in a Python script that is being
> called from the hook. When doing so, I am greeted with the following
> error:
>
> On Windows 10:
> Preparing worktree (detached HEAD cbfef18)
> fatal: Unable to create 'C:/Users/meh/Desktop/abc/.git/index.lock': No
> such file or directory
>
> On Arch Linux:
> Preparing worktree (detached HEAD cbfef18)
> fatal: Unable to create '/home/cosmin/Downloads/abc/.git/index.lock':
> Not a directory
>
> Is it forbidden to call this command from a hook?

pre-commit hook sets GIT_INDEX_FILE to this "index.lock" so you have the latest index content (which is not the same as from $GIT_DIR/index). This variable will interfere with any commands that work on a different worktree.

So you probably can still make it work by backing up $GIT_INDEX_FILE (in case you need it), then unset it before you use "git worktree" (or cd to it if you keep a permanent separate worktree for pre-commit activities). To make sure you don't have similar problems, you probably should do "env | grep GIT" from the hook and see if any other variables are set.

Show 6 quoted lines

> If yes, what kind of
> alternatives do I have? I need to make a copy of the repo in its HEAD
> state, process it and then decide if I will pass the current commit or
> not.
>
> Thanks! :)

-- 
Duy