Re: [PATCH] setup: warn about un-enabled extensions

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi,

On Tue, 14 Jul 2020, Derrick Stolee wrote:

> On 7/14/2020 11:27 AM, Junio C Hamano wrote:
> > Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
> >
> >>> If you don't mind, I was already going to squash Junio's commit into
> >>> mine (almost completely replacing mine) but I could add a small
> >>> commit on top that provides the following improvement to the error
> >>> message:
> >>
> >> I don't mind at all. I'd just like to know that v2.28.0 avoids confusing
> >> users in the same was as v2.28.0-rc0 confused me.
> >
> > In a nearby thread, Jonathan Nieder raised an interesting approach
> > to avoid confusing users, which I think (if I am reading him
> > correctly) makes sense (cf. <20200714040616.GA2208896@google.com>)
> >
> > What if we accept the extensions the code before the topic in
> > question that was merged in -rc0 introduced the "confusion" accepts
> > even in v0?  If we see extensions other than those handpicked and
> > grandfathered ones (which are presumably the ones we add later and
> > support in v1 and later repository versions) in a v0 repository, we
> > keep ignoring.  Also we'd loosen the overly strict code that
> > prevents upgrading from v0 to v1 in the presence of any extensions
> > in -rc0, so that the grandfathered ones will not prevent the
> > upgrading.
> >
> > The original reasoning behind the strict check was because the users
> > could have used extensions.frotz for their own use with their own
> > meaning, trusting that Git would simply ignore it, and an upgrade to
> > later version in which Git uses extensions.frotz for a purpose that
> > is unrelated to the reason why these users used would just break the
> > repository.
> >
> > But the ones that were (accidentally) honored in v0 couldn't have
> > been used by the users for the purposes other than how Git would use
> > them anyway, so there is no point to make them prevent the upgrade
> > of the repository version from v0 to v1.
> >
> > At least, that is how I understood the world would look like in
> > Jonathan's "different endgame".
> >
> > What do you three (Dscho, Derrick and Jonathan) think?
>
> If "v0" includes "core.repositoryFormatVersion is unset" then I
> would consider this to be a way to avoid all user pain, which is
> positive.

I concur.

> I'd be happy to test and review a patch that accomplishes this
> goal.

Wouldn't that just be a matter of extending your patch to re-set
`has_unhandled_extensions` also for `preciousObjects` and `partialClone`?

Ciao,
Dscho

>
> CC'ing Ed Thomson because this extension stuff affects other tools,
> like libgit2.
>
> Thanks,
> -Stolee
>
>