Subject: Re: bug#66670: [PATCH] Use buffer-local comment-continue in comment-indent-new-line

From: Stefan Kangas <[email-masked]>
Date: Wed, 12 Feb 2025 23:09:15 -0800

Stefan Monnier <[email-masked]> writes:

>>>>                       ;; Recreate comment-continue from comment-start.
>>>> -                     ;; FIXME: wrong if comment-continue was set explicitly!
>>>>                       ;; FIXME: use prev line's continuation if available.
>>>> -                     (comment-continue nil))
>>>> +                     (comment-continue (if (local-variable-p 'comment-continue)
>>>> +                                           comment-continue
>>>> +                                         nil)))
>>>
>>> Are you sure?  `comment-continue` is very rarely set globally.
>>> Usually it's set buffer-locally by `comment-normalize-vars`.
>>
>> Or by the major-mode!  But yes, I see your point, this patch is
>> effectively removing the (comment-continue nil) definition.
>
> Yup.
>
>> I guess that the (comment-continue nil) definition is there in the first
>> place so that comment-normalize-vars recalculates it based on
>> comment-start,
>
> Indeed, that's what the comment tries to say.
>
>> which is the comment prefix from the previous line?
>
> Something like that, yes.
>
>> So we therefore copy the prefix from the previous line?
>
> Not necessarily.  If the previous line was the beginning of the comment
> with "/*" we should use " *".
>
>> Should we just recalculate comment-continue directly in
>> comment-indent-new-line instead, if necessary?
>
> We could.  But we still need to decide whether to do that or to just
> trust the `comment-continue` value set by those major modes which set
> it by hand :-(

Spencer, what is the latest here?  Did you make any progress with this
patch?