Automatic updating exports wrong background color under emacsclient

[jcaw]

Problem

When using emacsclient with emacs --daemon as the server, automatic theme exporting stops working. The wrong background color is extracted. Here's an example of what happens when theme-magic-export-theme-mode is active and the theme is changed to zenburn:

To the top right, wal has a preview of the current colors. Color0 (the background color) is not the only color affected, but it is the most dramatic.

Manual theme exporting still works.

Possible Cause

What seems to be happening is the default face isn't setting its background color until after theme-magic's advice is processed, but this only happens to emacsclients. (I don't currently know what would cause that.)

This may be related to the server running as a terminal-based Emacs. I don't know how that architecture works.

[jcaw]

Possible Solution

A possible solution would be run the export function on an idle timer, so it only gets exported after emacsclient has completely finished updating the theme. However, this isn't a perfect solution. It delays updating. The Linux theme wouldn't start updating until after Emacs has completely updated and run any additional code.

Emacs theme is updated -> Emacs does work -> Linux theme is updated.

If a theme is updated during startup and the startup takes a while, the theme would only be exported after the startup has completely finished. I'd rather not add this universally because it's only necessary for daemons.

Temporary Hack

Three options that could work as temporary hacks:

• Running graphical emacs as normal and using (server-start) instead of using emacs --daemon works fine.
• Exporting the theme manually works fine.
• Instead of using theme-magic-export-theme-mode, evaluate the following snippet, which updates the theme on an idle timer instead:

(mapcar (lambda (func-name)
          (advice-add
           func-name
           :after
           (lambda (&rest _)
             (run-with-idle-timer 0.01 nil 'theme-magic-from-emacs--wrapper))))
        theme-magic--theming-functions)