Subject: 26.3; window-body-width wrong return value when display-line-numbers-mode is on
From: "Matsievskiy S.V." <[email-masked]>
To: [email-masked]
Date: Tue, 26 May 2020 13:50:38 +0300
List-Id: <debbugs-submit.debbugs.gnu.org>

`window-body-width` and `window-width` return wrong numbers when
`display-line-numbers-mode` is on.

For example:
```emacs-lisp
(message (format "Width without line numbers: %d" (window-body-width)))
(display-line-numbers-mode 1)
(message (format "Width with line numbers: %d" (window-body-width)))
```

return these lines:
```
Width without line numbers: 209
Width with line numbers: 209
```

This is obviously wrong since line numbers take some window space.
This breaks some packages that rely on `window-body-width` and
`window-width` to align strings. 

In GNU Emacs 26.3 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.24.20)
 of 2020-05-17, modified by Debian built on x86-csail-01
Windowing system distributor 'The X.Org Foundation', version
11.0.12008000
System Description:     Debian GNU/Linux bullseye/sid

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Mark set
Width without line numbers: 209
Width with line numbers: 209

Configured using:
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Major mode: Lisp Interaction

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