Re: [PATCH 1/1] Introduce "precious" file concept

[Duy Nguyen <pclouds@gmail.com>]

On Wed, Feb 20, 2019 at 4:19 PM Ævar Arnfjörð Bjarmason
<avarab@gmail.com> wrote:
> > I personally do not believe in "backup log"; if we can screw up and
> > can fail to stop an operation that must avoid losing info, then we
> > can screw up the same way and fail to design and implement "backup"
> > to save info before an operation loses it.
>
> Yes, there could be some unforseen interaction between git commands
> where we should have such a backup log, but did not think to implement
> it. I'd hope such cases would be reported, and we could fix them.
>
> But those sorts of cases aren't why we started discussing this, rather
> we *know* what the data shredding command interaction is, but there
> wasn't a consensus for just not shredding data by default by making
> users use "checkout -f" or "merge -f" to proceed. I.e. taking some
> variant of my "trashable" patch[1].
>
> > If we do a good job in
> > supporting "precious" in various operations, we can rely less on
> > "backup log" and still be safe ;-)
>
> Is noted in previous discussions[2] I think that's entirely
> implausible. I think at best the "precious" facility will be used to
> mark e.g *.o files as "don't check in, but don't clean (Makefile handles
> it)".
>
> Most git users are at the level of only knowing very basic
> add/commit/pull/push command interaction. I feel strongly that we need
> to make our tools safe to use by default, and not require some
> relatively advanced "precious"/attribute facility to be carefully
> configured in advance so we don't throw away uncommitted work on the
> likes of merge/checkout.

There is a trade off somewhere. "new user first" should not come at
the cost for more experienced users.

Making "git checkout/merge" abort while it's working before breaks
scripts. And requiring to mark trashable files manually duplicates a
lot of ignore patterns. Have a look at any .gitignore file, the
majority of them is for discardable files because "ignored" class was
created with those in mind (*.o and friends). So now you would need to
add more or less the same set of ignore rules in .gitattributes to
mark them trashable, and gitignore/gitattributes rules are not exactly
compatible, you can't just blindly copy them over. Every time you add
one more .gitignore rule, there's a good chance you need to add a
similar rule for trashable attribute.

Maybe we just add a new "newbie" config knob and turn on the safety
nets on. Leave the knob on by default. And I will turn it off in my
~/.gitconfig as soon as it's real.
-- 
Duy