GNU bug report logs - #78989
31.0.50; classes and methods inheritance (defclass) seq-contains-p

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Message #38 received at 78989 <at> debbugs.gnu.org (full text, mbox):

From: Pip Cet <pipcet <at> protonmail.com>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: 78989 <at> debbugs.gnu.org, Eli Zaretskii <eliz <at> gnu.org>,
 "Pierre L. Nageoire" <devel <at> pollock-nageoire.net>
Subject: Re: bug#78989: 31.0.50;
 classes and methods inheritance (defclass) seq-contains-p
Date: Sun, 13 Jul 2025 10:23:57 +0000

"Stefan Monnier" <monnier <at> iro.umontreal.ca> writes:

>> I'm convinced both of your patches will still produce
>> topologically inconsistent orderings.
>
> Not without emitting a warning along the way.

I'm very confused here.  Can you make sure you sent the right patch?
Or point out where the last patch emits a warning?  I just don't see any
code to do so.

>> That is because the information necessary to figure out how to break
>> an artificial "cycle" is lost the second we stop considering the
>> inheritance graph and limit ourselves to previously-linearized
>> ancestor lists.
>
> Indeed.  That's a choice between losing monotonicity and suffering from
> artificial-cycles.  You can't avoid both.  But years of experience in
> other languages told us that it's easier for programmers to deal with
> artificial cycles than with loss of monotonicity.

I'm baffled by that, but I'll take your word for it.

Pip

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