Images generated by code blocks not refreshed

[wmedrano]

• Arch Linux with "graphviz" installed
• Emacs 30.1 in graphical mode on Wayland
• org-preview-html-mode using eww

How to Reproduce

Reproduce

1. Prerequisite

Have graphviz installed. This should provide the dot command. Enable dot in org babel with Elisp:

(org-babel-do-load-languages
 'org-babel-load-languages
 '((dot . t)))

2. Create an org file with dot src code:

#+BEGIN_SRC dot :file dot.png
digraph {
  HelloWorld
}
#+END_SRC

3. Enable org-preview-html-mode

This may ask to evaluate dot (say yes). Org preview then shows an image with a circle with "HelloWorld".

4. Update the text

Run M-x org-preview-html-refresh. This may ask to evaluate the code, say yes.

#+BEGIN_SRC dot :file dot.png
digraph {
  ByeWorld
}
#+END_SRC

5. Result

• Preview still shows "HelloWorld"
• M-x find-file for "dot.png" opens an image that says "ByeWorld"

[wmedrano]

Feel free to close. This seems to be a problem with eww, but it makes preview mode for some use cases useless.

What's worse is that eww persists the cache even when reloading the entire Emacs session. May look into it more later, but I only got things to refresh by deleting the entire ~/.emacs.d/url/cache directory.

[wmedrano]

My current workaround so that I can have a good org-preview-html experience:

(defun url-is-cached-no-local-files (url-is-cached-fn &rest args)
  "Patch URL-IS-CACHED-FN with ARGS to return nil if the file is local.

Makes it so that eww does not cache local files.

See https://github.com/jakebox/org-preview-html/issues/23."
  (if (and (stringp (car args)) (string-prefix-p "file:///" (car args)))
      nil
    (apply url-is-cached-fn args)))

(advice-add 'url-is-cached :around #'url-is-cached-no-local-files)

[jakebox]

Sorry I never checked this out. Thanks for the detailed notes. I'm not sure about adding the advice to the package. Perhaps we could add this into the README?