Re: Lisp primitives and their calling of the change hooks

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Date: Tue, 09 Jan 2018 08:30:21 -0500
> 
> >> Not just convenience but also "obviously correct", i.e. more maintainable.
> > We obviously disagree about what's "correct" in this case, so this
> > argument doesn't convince me, exactly like my arguments didn't
> > convince you.
> 
> Calling `del_range` is "obviously correct" because it's higher level and
> guarantees we follow various rules, such as those of b-c-f/a-c-f.
> In contract `del_range_2` is a lower-level function which requires more
> care to use.

There are 3 other places in our sources that call del_range_2, so I
see no reason to fear of one more, or proclaim that "incorrect" or
"less obviously correct".

> > As for maintainability, I think this is beyond splitting hair, because
> > I cannot for the life of me see any difference in maintainability
> > between the two variants.
> 
> The fact that someone like Alan failed to notice the need for a call to
> update_compositions is good enough evidence for me.

No, it just is another manifestation of a known truism that patch
review is a very useful and efficient technique for catching bugs
before they happen.  We all make mistakes, and the fact that we do
doesn't necessarily mean the code we wrote is "incorrect" or
"difficult to maintain".