bug#22465: xwidget-webkit-scroll-behaviour = image is non-functional

[joakim@verona.se]

Paul Eggert <eggert@cs.ucla.edu> writes:

> joakim@verona.se wrote:
>> Perhaps someone still prefers the 'image method though.
>
> This seems unlikely, given that it recurses infinitely whenever it scrolls left
> or right. Anyway, thanks for following up. If nobody objects I would like to
> install the attached patch to emacs-25 to remove xwidget-webkit-scroll-behavior
> and therefore fix the bug.

I agree, please install this fix.

>
> From 58b7ecc4bcba46c775a7edca209587f034185861 Mon Sep 17 00:00:00 2001
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Sat, 7 May 2016 17:17:55 -0700
> Subject: [PATCH] Remove buggy non-native image scrolling
>
> This never worked, and could cause infinite recursion.
> Problem reported by Glenn Morris (Bug#22465).
> * lisp/xwidget.el (xwidget-webkit-scroll-behavior): Remove.
> All uses removed.
> ---
>  lisp/xwidget.el | 43 +++++++++----------------------------------
>  1 file changed, 9 insertions(+), 34 deletions(-)
>
> diff --git a/lisp/xwidget.el b/lisp/xwidget.el
> index 19f631f..7a0ca8b 100644
> --- a/lisp/xwidget.el
> +++ b/lisp/xwidget.el
> @@ -34,13 +34,6 @@
>  (require 'cl-lib)
>  (require 'bookmark)
>  
> -(defcustom xwidget-webkit-scroll-behavior 'native
> -  "Scrolling behavior of the webkit instance.
> -The possible values are: `native' or `image'."
> -  :version "25.1"
> -  :group 'frames   ; TODO add xwidgets group if more options are added
> -  :type '(choice (const native) (const image)))
> -
>  (declare-function make-xwidget "xwidget.c"
>                    (type title width height arguments &optional buffer))
>  (declare-function xwidget-set-adjustment "xwidget.c"
> @@ -141,40 +134,24 @@ xwidget-webkit-mode-map
>    "Keymap for `xwidget-webkit-mode'.")
>  
>  (defun xwidget-webkit-scroll-up ()
> -  "Scroll webkit up.
> -Depending on the value of `xwidget-webkit-scroll-behavior',
> -this scrolls in `native' fashion, or like `image-mode' would."
> +  "Scroll webkit up."
>    (interactive)
> -  (if (eq xwidget-webkit-scroll-behavior 'native)
> -      (xwidget-set-adjustment (xwidget-webkit-last-session) 'vertical t 50)
> -    (image-scroll-up)))
> +  (xwidget-set-adjustment (xwidget-webkit-last-session) 'vertical t 50))
>  
>  (defun xwidget-webkit-scroll-down ()
> -  "Scroll webkit down.
> -Depending on the value of `xwidget-webkit-scroll-behavior',
> -this scrolls in `native' fashion, or like `image-mode' would."
> +  "Scroll webkit down."
>    (interactive)
> -  (if (eq xwidget-webkit-scroll-behavior 'native)
> -      (xwidget-set-adjustment (xwidget-webkit-last-session) 'vertical t -50)
> -    (image-scroll-down)))
> +  (xwidget-set-adjustment (xwidget-webkit-last-session) 'vertical t -50))
>  
>  (defun xwidget-webkit-scroll-forward ()
> -  "Scroll webkit forwards.
> -Depending on the value of `xwidget-webkit-scroll-behavior',
> -this scrolls in `native' fashion, or like `image-mode' would."
> +  "Scroll webkit forwards."
>    (interactive)
> -  (if (eq xwidget-webkit-scroll-behavior 'native)
> -      (xwidget-set-adjustment (xwidget-webkit-last-session) 'horizontal t 50)
> -    (xwidget-webkit-scroll-forward)))   ; FIXME infloop!
> +  (xwidget-set-adjustment (xwidget-webkit-last-session) 'horizontal t 50))
>  
>  (defun xwidget-webkit-scroll-backward ()
> -  "Scroll webkit backwards.
> -Depending on the value of `xwidget-webkit-scroll-behavior',
> -this scrolls in `native' fashion, or like `image-mode' would."
> +  "Scroll webkit backwards."
>    (interactive)
> -  (if (eq xwidget-webkit-scroll-behavior 'native)
> -      (xwidget-set-adjustment (xwidget-webkit-last-session) 'horizontal t -50)
> -    (xwidget-webkit-scroll-backward))) ; FIXME infloop!
> +  (xwidget-set-adjustment (xwidget-webkit-last-session) 'horizontal t -50))
>  
>  
>  ;; The xwidget event needs to go into a higher level handler
> @@ -417,9 +394,7 @@ xwidget-webkit-adjust-size-to-content
>  (defun xwidget-webkit-adjust-size-dispatch ()
>    "Adjust size according to mode."
>    (interactive)
> -  (if (eq xwidget-webkit-scroll-behavior 'native)
> -      (xwidget-webkit-adjust-size-to-window)
> -    (xwidget-webkit-adjust-size-to-content))
> +  (xwidget-webkit-adjust-size-to-window)
>    ;; The recenter is intended to correct a visual glitch.
>    ;; It errors out if the buffer isn't visible, but then we don't get
>    ;; the glitch, so silence errors.

-- 
Joakim Verona