Subject: bug#29597: 26.0.90; line-number-display-width returns incorrect width

From: Eli Zaretskii <[email-masked]>
Date: Thu, 07 Dec 2017 08:55:05 +0000

On December 7, 2017 5:34:51 AM GMT+00:00, Paul Rankin <[email-masked]> wrote:
> After reading #28248[1] I’m not sure if this is now fixed on the
> release branch, but on 26.0.90 function line-number-display-width
> returns an off-by-2 incorrect value.
> 
> See attached screenshot or [2] also.
> 
> To reproduce:
> 
> 1. emacs -Q (or emacs -Q -nw)
> 2. (display-line-numbers-mode)
> 3. (line-number-display-width)
> 
> Expected results:
> 4
> 
> Actual results:
> 2
> 
> Configuration:
> 
> GNU Emacs 26.0.90 (build 1, x86_64-apple-darwin17.2.0, NS
> appkit-1561.10 Version 10.13.1 (Build 17B48)) of 2017-11-05
> macOS 10.13.1 (17B1003)
> 
> [1]: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=28248
> [2]: https://imgur.com/a/kuZjA

This is not a bug, see the doc string on the release branch.  The latest code on the branch has more flexible API when the optional argument is non-nil.