Lisp error: (wrong-type-argument stringp w3m-filter-prefer-lazy-images)

[Michael Pagan <pegzmasta@xxxxxxxxxxxxxx>]

I can't browse webpages with emacs-w3m since the latest commit about 19 hours
ago, [1604c85][0] (adds new filter). 

GNU Emacs version:
GNU Emacs 26.2 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.18.9) of 2019-04-27

Compile-Log (errors):
w3m-ucs.el:46:1:Error: Cannot open load file: No such file or directory, un-define

Backtrace:
Debugger entered--Lisp error: (wrong-type-argument stringp w3m-filter-prefer-lazy-images)
  (string-match w3m-filter-prefer-lazy-images "about:")
  (w3m-filter "about:")
  (w3m-create-page "about:" "text/html" iso-2022-7bit #<buffer *w3m*>)
  (w3m--retrieve-and-render--handler-function "about:" nil #<buffer *w3m*> (23763 30548 732670 107000) nil "text/html")
  (#f(compiled-function (G340 G341 G342 G343 G344 G345 G346 type) #<bytecode 0x1071fa5>) ----current-buffer--193-- ----temp-buffer--192-- --silent-- --arrival-time-- --page-buffer-- --charset-- --url-- "text/html")
  (apply #f(compiled-function (G340 G341 G342 G343 G344 G345 G346 type) #<bytecode 0x1071fa5>) ----current-buffer--193-- ----temp-buffer--192-- --silent-- --arrival-time-- --page-buffer-- --charset-- --url-- "text/html")
  ((lambda (&rest --cl-rest--) (apply (function #f(compiled-function (G340 G341 G342 G343 G344 G345 G346 type) #<bytecode 0x1071fa5>)) (quote ----current-buffer--193--) (quote ----temp-buffer--192--) (quote --silent--) (quote --arrival-time--) (quote --page-buffer--) (quote --charset--) (quote --url--) --cl-rest--)) "text/html")
  (w3m-retrieve-and-render "about:" nil nil nil nil ((lambda (&rest --cl-rest--) (apply (function #f(compiled-function (G373 G374 G375 G376 G377 G378 G379 G380 G381 G382 action) #<bytecode 0x1dd0d11>)) (quote --reuse-history--) (quote --history-position--) (quote --name--) (quote --referer--) (quote --post-data--) (quote --charset--) (quote --redisplay--) (quote --reload--) (quote --url--) (quote --orig--) --cl-rest--))))
  (w3m--goto-url--valid-url "about:" nil nil nil nil nil nil nil nil)
  (w3m-goto-url "about:")
  (w3m "about:" nil t)
  (funcall-interactively w3m "about:" nil t)
  (call-interactively w3m record nil)
  (command-execute w3m record)
  (execute-extended-command nil "w3m" "w3m")
  (funcall-interactively execute-extended-command nil "w3m" "w3m")
  (call-interactively execute-extended-command nil nil)
  (command-execute execute-extended-command)

I configured Emacs to update all of my packages (emacs-w3m, included) everyday,
so today I was surprised when I “M-x w3m”, and was sent straight to a *Backtrace*
buffer.

I’ve made a workaround for now so that I can still use emacs-w3m:
(with-eval-after-load "w3m"
  (use-package w3m-filter
    :ensure nil
    :config
    ;; Workaround for `emacs-w3m' commit: <https://github.com/emacs-w3m/emacs-w3m/commit/1604c85039779efd4d2cfa5743a1930bb37ee9a4>
    (setq w3m-filter-configuration (butlast w3m-filter-configuration 1))
    (setq w3m-filter-configuration
          (append '((nil
                     ("Prefer a lazy image specified with data-src= in img tags" "img タグ内の data-src= で指定される遅延画像を優先します")
                     w3m-filter-prefer-lazy-images)) w3m-filter-configuration))))

This workaround deletes the ‘w3m-filter-prefer-lazy-images’ list (with
value of ’t) from ‘w3m-filter-configuration, and then appends the
deleted list with a new value of nil to said variable.  Now emacs-w3m
loads webpages again; however, since I set
‘w3m-default-display-inline-images’ to ’t, I believe that I can
benefit from the newly added filter if it was modified some more.
Alas, I am just a casual emacs user, and my only experience with elisp
is with modifying my init.el file… that’s it.

Is there a way for me to use this new filter?  Also, what benefits
would this filter provide; faster load time for webpages?

I welcome your feedback!

[0]: https://github.com/emacs-w3m/emacs-w3m/commit/1604c85039779efd4d2cfa5743a1930bb37ee9a4
-- 
Michael Pagan (pegzmasta) | Casual GNU Emacs user
GPG Key ID: B942 AD12 82B1 6D14 27A0  86AE 119E 451E 71B4 6D72