Re: RFC: Supporting .git/hooks/$NAME.d/* && /etc/git/hooks/$NAME.d/*

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

On Tue, Apr 26, 2016 at 3:40 PM, Marc Branchaud <marcnarc@xiplink.com> wrote:
> On 2016-04-26 06:58 AM, Ævar Arnfjörð Bjarmason wrote:
>>
>> Makes sense to have an experimental.* config tree for git for stuff like this.
>
> I disagree.
>
> * If the point is to express some kind of warning to users, I think the
> community has been much better served by leaving experimental settings
> undocumented (or documented only in unmerged topic branches).  It feels like
> an experimental.* tree is a doorway to putting experimental features in
> official releases, which seems odd considering that (IMHO) git has so far
> done very well with the carefully-planned-out integration of all sorts of
> features.
>
> * Part of the experiment is coming up with appropriate configuration knobs,
> including where those knobs should live.  Often such considerations lead to a
> better implementation for the feature.  Dumping things into an experimental.*
> tree would merely postpone that part of the feature's design.
>
> * Such a tree creates a flag day when the experimental feature eventually
> becomes a "real" feature. That'll annoy any early adopters. Sure, they
> *should* be prepared to deal with config tree bike-shedding, but still that
> extra churn seems unnecessary.

By "stuff like this", yeah I did mean, and I assume Junio means,
putting "experimental" features in official releases.

E.g. perl does this, if you type "perldoc experimental" on a Linux box
you'll get the documentation.

Basically you can look at patches to a project on a spectrum of:

 1. You hacked something up locally
 2. It's in someone's *.git repo as a POC
 3. It's a third-party patch series used by a bunch of people
 4. In an official release but documented as experimental
 5. In an official release as a first-rate feature

Something like an experimental.WHATEVER=bool flag provides #4.

I think aside from this feature just leaving these things undocumented
really provides the worst of both worlds.

Now you have some feature that's undocumented *because* you're not
sure about it, but you can't ever be sure about it unless people
actually use it, and if it's not documented at all effectively it's as
visible as some third-party patch series. I.e. only people really
involved in the project will ever use it.

Which is why perl has the "experimental" subsystem, it allows for
playing around with features the maintainers aren't quite sure about
in official releases, and the users know they're opting in to trying
something unstable that may go away or have its semantics changed from
under them.