Re: [Emacs-diffs] master de76a16: Performance improvements for vc-hg

[Eli Zaretskii <eliz@gnu.org>]

> Cc: monnier@IRO.UMontreal.CA, emacs-devel@gnu.org
> From: Daniel Colascione <dancol@dancol.org>
> Date: Mon, 8 Feb 2016 12:28:29 -0800
> 
> >> I find the information useful, and we can now get it cheaply.
> > 
> > We are paying a non-trivial price as a project for that information,
> > see for example bug#21559.  Maybe it should be an option, off by
> > default?
> 
> bug#21559 is a corner case.

It could be the tip of an iceberg.

> vc has been in place for decades, and is one of the things that makes
> programming on Emacs pleasant. I'm not in favor of just removing the
> feature because there are a few unfixed bugs. There is nothing
> fundamentally wrong with the model.
> 
> Making vc itself an option that's off by default makes no sense.

I didn't suggest making VC an option.  I suggested to make running the
"status" command optional.

> Under what circumstances should a user enable the feature?

When she wants the mode line to display whatever it is that we display
there.

"When
> he's willing to pay the cost" is the answer I expect.


> How is he supposed to know the feature even exists?

How do users know about the existence of any other feature?  This one
is no different.

> There is no reason that vc integration can't work well and be on by
> default. It was working before my change; now it works better.

For a single VCS, and not the most important one.

The problem with calling "status" is that locks the repository, makes
changes in the filesystem, and interferes with Emacs features that are
sensitive to changes in the filesystem.  Making it optional could be
the only solution to that conundrum.

> A reasonable performance improvement should not be an occasion for
> discussing the removal of a feature made faster.

No one suggested removing the feature, this is a misunderstanding.