From: Karl Fogel <kfogel@red-bean.com>
To: Emacs Devel <emacs-devel@gnu.org>
Cc: Stefan Monnier <monnier@iro.umontreal.ca>
Subject: Re: [elpa] externals/org ee0961ba31: lisp/org-table.el: fix warning about `eq' usage
Date: Wed, 01 Nov 2023 01:07:50 -0500 [thread overview]
Message-ID: <87pm0u9fbd.fsf@red-bean.com> (raw)
In-Reply-To: <jwvwmv2i3b7.fsf-monnier+emacs@gnu.org>
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Stefan Monnier wrote:
>> This change does not affect the behavior of
>> `org-table-make-reference' because `eq' treats all instances
>> of the empty string as the same object anyway, e.g.,
>> `(eq (string-trim "aaabbb" "a+" "b+") "")' ==> t.
>
>Not quite so: (eq (string-to-multibyte "") "") => nil
Thank you for noticing this, Stefan.
I did many tests with `eq' and various kinds of generated empty
strings before writing that commit message -- but, alas, I didn't
think of testing with a multibyte string. (I also looked in the
documentation, and the fact that there was no explicit mention of
all empty strings being the same object should have tipped me
off!)
So, I believe this means there is an error in that commit message.
I've attached the commitinfo below for easy reference, with
'inline' disposition.
However, the code change itself remains correct... I think? That
is: the previous code presumably had a latent bug, in that there
*could* have been times when the `eq' test would fail when
comparing against a multibyte empty string.
I don't know much about how Org Mode gets merged into Emacs, nor
whether there are opportunities for rebasing anywhere along the
way in that process. If there's a way to update that commit
message, then I'd do so (I can post a new one here). But if
there's no such opportunity, then so be it: I'll be on the
permanent record with a technical mistake in a log message. I'm
sure it wouldn't be the first time :-/.
Best regards,
-Karl
[-- Attachment #2: commit ee0961ba317 --]
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commit ee0961ba3170f7bc89c2f6fabda4b6ea2e7a2c88
Author: Karl Fogel <kfogel@red-bean.com>
AuthorDate: Mon Oct 30 10:33:29 2023 -0500
Commit: Bastien Guerry <bzg@gnu.org>
CommitDate: Tue Oct 31 21:38:23 2023 +0100
lisp/org-table.el: fix warning about `eq' usage
* lisp/org-table.el (org-table-make-reference): Use `equal' instead of
`eq' to compare strings.
This change makes the following warning go away:
Warning (comp): org-table.el:2867:23: \
Warning: `eq' called with literal string that may never match (arg 2)
This change does not affect the behavior of `org-table-make-reference'
because `eq' treats all instances of the empty string as the same
object anyway, e.g., `(eq (string-trim "aaabbb" "a+" "b+") "")' ==> t.
The only effect of this change is to eliminate the warning.
M lisp/org-table.el
next prev parent reply other threads:[~2023-11-01 6:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <169879312007.20093.7465071871654518215@vcs2.savannah.gnu.org>
[not found] ` <20231031225840.6A0FEC06553@vcs2.savannah.gnu.org>
2023-11-01 3:05 ` [elpa] externals/org ee0961ba31: lisp/org-table.el: fix warning about `eq' usage Stefan Monnier
2023-11-01 6:07 ` Karl Fogel [this message]
2023-11-01 9:04 ` Bastien
2023-11-01 11:31 ` Stefan Monnier
2023-11-01 16:22 ` Karl Fogel
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