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bug#56255: 28.1.50; sxhash-equal does not change when object is modified
From: |
Lars Ingebrigtsen |
Subject: |
bug#56255: 28.1.50; sxhash-equal does not change when object is modified |
Date: |
Tue, 28 Jun 2022 01:00:33 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) |
Lars Ingebrigtsen <larsi@gnus.org> writes:
> So I think the doc string overstates things.
>
> --
> If (equal A B), then (= (sxhash-equal A) (sxhash-equal B)).
> --
>
> Is not remotely true, but:
>
> --
> If (= (sxhash-equal A) (sxhash-equal B)) then it's quite likely that
> (equal A B), but the opposite is not true for deeply nested structures.
> --
Sorry, that's all wrong, and what the doc string says is true. That is,
if they're equal, then the hash is =.
But (= (sxhash-equal A) (sxhash-equal B)) does not imply that
(equal A B), and the doc string should say that explicitly.
It's the manual that's wrong here:
If the two objects are not ‘equal’, the values returned by
‘sxhash-equal’ are usually different, but not always; once in a
rare while, by luck, you will encounter two distinct-looking
objects that give the same result from ‘sxhash-equal’.
It's not "once in a rare while" for deeply nested structures.
--
(domestic pets only, the antidote for overdose, milk.)
bloggy blog: http://lars.ingebrigtsen.no
- bug#56255: 28.1.50; sxhash-equal does not change when object is modified, Ihor Radchenko, 2022/06/27
- bug#56255: 28.1.50; sxhash-equal does not change when object is modified, Lars Ingebrigtsen, 2022/06/27
- bug#56255: 28.1.50; sxhash-equal does not change when object is modified,
Lars Ingebrigtsen <=
- bug#56255: 28.1.50; sxhash-equal does not change when object is modified, Lars Ingebrigtsen, 2022/06/28
- bug#56255: 28.1.50; sxhash-equal does not change when object is modified, Ihor Radchenko, 2022/06/28
- bug#56255: 28.1.50; sxhash-equal does not change when object is modified, Lars Ingebrigtsen, 2022/06/29
- bug#56255: 28.1.50; sxhash-equal does not change when object is modified, Ihor Radchenko, 2022/06/29
- bug#56255: 28.1.50; sxhash-equal does not change when object is modified, Lars Ingebrigtsen, 2022/06/29
- bug#56255: 28.1.50; sxhash-equal does not change when object is modified, Ihor Radchenko, 2022/06/29
- bug#56255: 28.1.50; sxhash-equal does not change when object is modified, Lars Ingebrigtsen, 2022/06/29
- bug#56255: 28.1.50; sxhash-equal does not change when object is modified, Ihor Radchenko, 2022/06/29
- bug#56255: 28.1.50; sxhash-equal does not change when object is modified, Lars Ingebrigtsen, 2022/06/30
- bug#56255: 28.1.50; sxhash-equal does not change when object is modified, Ihor Radchenko, 2022/06/30