Re: [PATCH v2] hooks: propose project configured hooks

From: Derrick Stolee <stolee@gmail.com>
Date: Apr 7, 2021, 13:09 UTC
Message-ID: <9af3770f-204b-253b-d7f2-c9d5e7cf2fdb@gmail.com>
In-Reply-To: <87tuoijzsy.fsf@evledraar.gmail.com>

On 4/7/2021 3:53 AM, Ævar Arnfjörð Bjarmason wrote:

Show 18 quoted lines

> 
> On Wed, Apr 07 2021, brian m. carlson wrote:
>>
>> I continue to have serious reservations about this series and approach,
>> and I'm not sure that any proposal we can adopt here will address the
>> security concerns.  To be frank, I don't think this proposal should move
>> forward in its current state or otherwise, since I think the security
>> problems are inherent in this approach and fundamentally can't be fixed.
>>
>> This is, as should be obvious from my email address, my personal
>> opinion, despite my reference to my employer above.  Unless otherwise
>> stated, I don't speak for my employer and they don't speak for me.
> 
> I agree with pretty much every word you said, in particular the social
> engineering aspect of this. In past mails I've referred to elsewhere
> I've proposed some Emacs-like "ask" facility for git, but you've
> convinced me that that default would be a bad idea for the "user just
> clicks yes no matter what" reasons you noted.

These replies definitely speak from a perspective common to mine. This is very dangerous territory and should be handled carefully.

There is also a legitimate user need to use hooks _to contribute_ to some repositories. Hooks are not needed to read the repositories or interact with them as a document.

The current mechanisms require ad-hoc approaches that are custom to each project, so there would be value in creating a standard inside the Git client itself. I think the proposal goes too far in making this an automatic configuration, either because it assumes trust or assumes sufficient skepticism on behalf of the users. Either is not acceptable for the Git project.

Here are the hard lines I draw:

1. This should not happen in "git clone" (other than maybe a message
   over stderr that hooks are available to be configured through a
   different command).

2. Hooks should not update in "git checkout" (other than a message
   that hooks have updated).

3. Whatever document triggers a hook configuration should live at
   HEAD and should not be configured or updated until HEAD has been
   updated by one Git command (git clone, git checkout), time
   passes for the user to inspect the worktree, then _another_
   command (git hooks?) is run manually to reconfigure the hooks.

I think there is a potential way forward if these items are followed.

But I'd like to ask a different question: What problems are these custom hooks solving, and can Git solve those problems in-core?

If we care about checking commits for format or something, is that a common enough problem that we could implement it in Git itself and enable it through a Git config option? It might be interesting to pursue this direction and maybe we'll solve 80% of the need with extensions like that.

I'm aware of some hooks that insert things like a Gerrit change-id that would probably not be appropriate for such an in-core change.

There is always the extreme option of requiring users to use a specific fork of Git in order to work with your repository. That has its own pains, believe me. But, it does allow for the ultimate flexibility in how these things are done. Optional config can be enabled by default. Hooks can be replaced with in-core functionality.

Thanks, -Stolee