Setting combobulate-key-prefix on :custom keyword doesn't work when combobulate is installed using use-package :vc keyword

[bormoge]

When I tried to change the value of combobulate-key-prefix from "C-c o" to "s-o" it didn't work. This is the configuration I used to install combobulate:

(use-package combobulate
  :vc (:url "https://github.com/mickeynp/combobulate"
       :rev :newest
       :branch "master"
       :vc-backend Git)
  :ensure t
  :defer t
  :custom
  (combobulate-key-prefix "s-o")
  :hook ((prog-mode . combobulate-mode)))

So I went into the code to see what was causing this, but I couldn't find the specific root of this bug. Here is what I found:

• combobulate-key-prefix is located in combobulate-settings.el
• Lines 417 and 418 of combobulate-setup.el are the ones that create combobulate-key-map using the prefix, so I assume combobulate-setup.el is loaded before the user can change the value of combobulate-key-prefix.
• Creating a previous variable named the same as combobulate-key-prefix and assigning that value to the original variable by modifying the original code does work. For that I used this line of code:
  (defcustom combobulate-key-prefix (if combobulate-key-prefix combobulate-key-prefix "C-c o")
• Later, I tested the original example in the README. That example does work, so the bug must be related to how combobulate is installed. Original example:

(use-package combobulate
   :custom
   ;; You can customize Combobulate's key prefix here.
   ;; Note that you may have to restart Emacs for this to take effect!
   (combobulate-key-prefix "C-c o")
   :hook ((prog-mode . combobulate-mode))
   ;; Amend this to the directory where you keep Combobulate's source
   ;; code.
   :load-path ("path-to-git-checkout-of-combobulate"))

• The main difference between both ways of installing combobulate seems to be that the :vc keyword automatically generates two files, combobulate-pkg.el and combobulate-autoloads.el. Specifically, I noticed combobulate-autoloads.el has these lines of code starting at 131

(autoload 'combobulate-mode "combobulate-setup" "\
Navigate and edit by syntactic constructs.

This is a helper command that tries to activate the right
Combobulate minor mode suitable for the current buffer.

(fn &optional ARG &rest _)" t)

• This auto-generated code must be related to line 498 of combobulate-setup.el.

For now this is what I found about this bug.

[mickeynp]

Thanks for investigating. I'll mark it as a bug.