Re: Reconsider defaults for use-package-vc-prefer-newest

[Eli Zaretskii <eliz@gnu.org>]

> From: "Martin Edström" <meedstrom@runbox.eu>
> CC: "emacs-devel" <emacs-devel@gnu.org>
> Date: Mon, 16 Sep 2024 18:15:45 +0200 (CEST)
> 
> Okay, I'll accept that for the command package-vc-install, as I have not thought much about its use cases.  
> 
> I want to call attention to the old use-package :vc, shipped under the confusing name vc-use-package [1], that people could install on Emacs 29 and earlier.  The Emacs 30 use-package :vc is a drop-in almost 1:1 replacement for this thing.  It had the opposite default behavior from the default Emacs 30 is about to have.  That change needs justification, not the other way around!
> 
> [1] https://github.com/slotThe/vc-use-package

That's a different package, so I don't see why we should necessarily
follow its decisions.  When users migrate to use-package :vc, they
should expect some changes in the default behavior.

> > > I should also point out that the catastrophe occurs not at release time, but years afterwards, when we're on Emacs 31, 32, 33... but devs still want to support Emacs 30, getting worse with time. So I do hope that it will be possible to change a setting like this with Emacs 30.2 or some other "bugfix" release.
> > 
> > There's no reason to do this for user options, since customizing an
> > option if the user doesn't like its default is easy.
> 
> You cannot rely on users to configure this kind of thing for themselves, most of them would not know the reason why things broke. It is not a matter of "liking" the default, since breakage in one direction would be much more severe than is possible to encounter in the other direction (years out of date vs. slightly too new).

Nowadays an Internet search will bring the answers very quickly and
efficiently.  And if that's not enough, there are enough user-level
help forums where people could ask questions and get useful answers.

IOW, "not a catastrophe".

> It is absolutely Emacs' responsibility, at least as long as stability for users is desired. Isn't it the reason to favor conservative defaults? Avoiding breakage? I get this new default comes from a good place, intending stability, but it is a radical departure from what has been the norm established by Straight/Quelpa/el-get and their use-package integrations, and that will work against stability.  

We can only be responsible for stability when our own implementation
and decisions are concerned.  We cannot be expected to blindly follow
someone else's decision in the name of "stability" for users who
switch from other packages, this kind of expectation is completely
unreasonable.

> > I consider advancing Package-Version when significant changes are made
> > a simple and uncontroversial thing to do for any package developer.  I
> > cannot imagine why someone who wants their package in good shape to
> > regard this as some annoyance.
> 
> This email discussion risks getting long, but let me know if you want me to describe why I do not find it simple.  For now, I believe the relevant thing from Emacs' perspective is that there does exist developers who will not advance Package-Version, nevermind why.

Well, simple or not, it is their act to get together.  Not ours.

Also, if we want to go an extra mile, I suggested a couple more
measures that would delineate the issue to unsuspecting users.