GNU bug report logs - #75557
gnus-highlight-selected-tree is broken (fix)

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Pranshu Sharma <pranshu <at> bauherren.ovh>
To: bug-gnu-emacs <at> gnu.org
Subject: gnus-highlight-selected-tree is broken (fix)
Date: Wed, 15 Jan 2025 00:03:40 +1000

[Message part 1 (text/plain, inline)]

seems like buffer-live-p does not accept string buffer names anymore

[Message part 2 (text/x-diff, inline)]

diff --git a/lisp/gnus/gnus-salt.el b/lisp/gnus/gnus-salt.el
index 6514d8d4174..75daf7e7cfa 100644
--- a/lisp/gnus/gnus-salt.el
+++ b/lisp/gnus/gnus-salt.el
@@ -808,7 +808,7 @@ gnus-tree-perhaps-minimize
 
 (defun gnus-highlight-selected-tree (article)
   "Highlight the selected article in the tree."
-  (when (buffer-live-p gnus-tree-buffer)
+  (when (buffer-live-p (get-buffer gnus-tree-buffer))
     (let ((buf (current-buffer))
 	  region)
       (set-buffer gnus-tree-buffer)

[Message part 3 (text/plain, inline)]

-- 
Pranshu Sharma <https://p.bauherren.ovh>

Message #8 received at 75557 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Kangas <stefankangas <at> gmail.com>
To: Pranshu Sharma <pranshu <at> bauherren.ovh>
Cc: Eli Zaretskii <eliz <at> gnu.org>, Stefan Monnier <monnier <at> iro.umontreal.ca>,
 75557 <at> debbugs.gnu.org
Subject: Re: bug#75557: gnus-highlight-selected-tree is broken (fix)
Date: Sat, 1 Mar 2025 20:04:45 -0800

fixed 75557 31.1
thanks

Pranshu Sharma <pranshu <at> bauherren.ovh> writes:

> seems like buffer-live-p does not accept string buffer names anymore

It actually never did.

I installed the below change on master (in your name), thanks.

>
> diff --git a/lisp/gnus/gnus-salt.el b/lisp/gnus/gnus-salt.el
> index 6514d8d4174..75daf7e7cfa 100644
> --- a/lisp/gnus/gnus-salt.el
> +++ b/lisp/gnus/gnus-salt.el
> @@ -808,7 +808,7 @@ gnus-tree-perhaps-minimize
>
>  (defun gnus-highlight-selected-tree (article)
>    "Highlight the selected article in the tree."
> -  (when (buffer-live-p gnus-tree-buffer)
> +  (when (buffer-live-p (get-buffer gnus-tree-buffer))
>      (let ((buf (current-buffer))
>  	  region)
>        (set-buffer gnus-tree-buffer)

My only question is if we should perhaps make `buffer-live-p` throw an
error in case it is passed something of the wrong type.  Yes, it is a
backwards-incompatible change, but OTOH it would catch real bugs like
the above, instead of silently returning nil.

For example, we can currently do all of this nonsense:

    (buffer-live-p 123)                          => nil
    (buffer-live-p [foo])                        => nil
    (buffer-live-p (make-symbol "foo"))          => nil
    (buffer-live-p (lambda () (message "foo")))  => nil

Eli, Stefan, WDYT?

Message #13 received at 75557 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Stefan Kangas <stefankangas <at> gmail.com>
Cc: Eli Zaretskii <eliz <at> gnu.org>, Pranshu Sharma <pranshu <at> bauherren.ovh>,
 75557 <at> debbugs.gnu.org
Subject: Re: bug#75557: gnus-highlight-selected-tree is broken (fix)
Date: Sat, 01 Mar 2025 23:30:55 -0500

> My only question is if we should perhaps make `buffer-live-p` throw an
> error in case it is passed something of the wrong type.  Yes, it is a
> backwards-incompatible change, but OTOH it would catch real bugs like
> the above, instead of silently returning nil.
>
> For example, we can currently do all of this nonsense:
>
>     (buffer-live-p 123)                          => nil
>     (buffer-live-p [foo])                        => nil
>     (buffer-live-p (make-symbol "foo"))          => nil
>     (buffer-live-p (lambda () (message "foo")))  => nil
>
> Eli, Stefan, WDYT?

I'm pretty sure it would introduce bugs because I know I wrote code
which relies on `buffer-live-p` behaving "like a type check"
(i.e. accepting any object).
I'd be surprised if I was the only one.


        Stefan "who doesn't like the tendency of ELisp functions to
                accept buffer names in place of buffer objects."

Message #18 received at 75557-done <at> debbugs.gnu.org (full text, mbox):

From: Stefan Kangas <stefankangas <at> gmail.com>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: Eli Zaretskii <eliz <at> gnu.org>, Pranshu Sharma <pranshu <at> bauherren.ovh>,
 75557-done <at> debbugs.gnu.org
Subject: Re: bug#75557: gnus-highlight-selected-tree is broken (fix)
Date: Sat, 1 Mar 2025 20:32:59 -0800

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

>> My only question is if we should perhaps make `buffer-live-p` throw an
>> error in case it is passed something of the wrong type.  Yes, it is a
>> backwards-incompatible change, but OTOH it would catch real bugs like
>> the above, instead of silently returning nil.
>>
>> For example, we can currently do all of this nonsense:
>>
>>     (buffer-live-p 123)                          => nil
>>     (buffer-live-p [foo])                        => nil
>>     (buffer-live-p (make-symbol "foo"))          => nil
>>     (buffer-live-p (lambda () (message "foo")))  => nil
>>
>> Eli, Stefan, WDYT?
>
> I'm pretty sure it would introduce bugs because I know I wrote code
> which relies on `buffer-live-p` behaving "like a type check"
> (i.e. accepting any object).
> I'd be surprised if I was the only one.

OK, then I guess there's not much more to do here.

I'm therefore closing this bug report.

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