Possible bug: Toggling minor mode with zero in init file breaks ido

[nicolaus1990]

Toggling minor mode off with zero in init-file, will break ido. For example: When C-x C-f, following error will appear:
Error in post-command-hook (ido-exhibit): (void-function ido-completions).

I don't know if this is an error, but it's not what I was expecting.

Here an init file that reproduces the error: (unfortunately I use 'use-package', but I hope it's understandable and init file should run as is). The error will not be there if one comments out (ido-vertical-mode 0). This error seems to only happen when (ido-vertical-mode 0) is called in init-file.

;;;;;;;;;;; 
;(package-initialize)
(require 'package)


(setq myPackageRepos '( ("melpa-stable" . "http://stable.melpa.org/packages/")
  ("melpa" . "http://melpa.org/packages/")
  ("marmalade" . "http://marmalade-repo.org/packages/")
  ("gnu" . "http://elpa.gnu.org/packages/")
))
(dolist (xs myPackageRepos)
  (unless (assoc-default (car xs) package-archives)
        (add-to-list 'package-archives
	  xs t)))

(package-initialize)

(unless (package-installed-p 'use-package)
  (package-refresh-contents)
  (package-install 'use-package))
;(eval-when-compile 
;  (require 'use-package))

;; use-package.el is no longer needed at runtime, which means that this at the
;; top will further reduce load time:
(eval-when-compile
  (require 'use-package))

;; If the package takes longer than 0.1s to load, you will see a message to
;; indicate this loading activity in the *Messages* buffer. The same will
;; happen for configuration, or :config blocks that take longer than 0.1s to
;; execute.
(setq use-package-verbose t)

;(setq use-package-always-defer t) ;;Unless :demand t
(setq use-package-always-ensure t)
;(require 'use-package)


;;; Ido: When typing "C-x b" ignore certain buffers.
(defvar ido-dont-ignore-buffer-names '("*grep*"))
(defun ido-ignore-most-star-buffers (name)
  (and
   (string-match-p "^*" name);Buffername starts with a star.
   (not (member name ido-dont-ignore-buffer-names))))


;;Note: Use C-j to make ido accept input as it is.
(use-package ido 
  :ensure t
  :init
  (progn
    (ido-mode 1)
    (ido-everywhere 1)
    ;; ido-use-faces is being set to nil because of flx highlights (see flx-ido)
    ;; (setq ido-default-buffer-method 'selected-window)
    (setq ido-ignore-buffers (list "\\` " #'ido-ignore-most-star-buffers))
))


(use-package ido-vertical-mode
  ;;List items vertically instead of horizontally and in brackets.
  ;:disabled
  :ensure t
  :after (ido)
  :config
  ;;Add colors
  (setq ido-use-faces t)
  (set-face-attribute 'ido-vertical-first-match-face nil
                      :background "#e5b7c0")
  (set-face-attribute 'ido-vertical-only-match-face nil
                      :background "#e52b50"
                      :foreground "white")
  (set-face-attribute 'ido-vertical-match-face nil
                      :foreground "#b00000")
  (setq ido-vertical-show-count t)
  ;;Enable
  (ido-mode 1)
  (ido-vertical-mode 0)
  ;(setq ido-vertical-define-keys 'C-n-and-C-p-only)
)

[pierre-rouleau]

I have seen the same issue with a simpler use of the package.

I have:

    (use-package ido-vertical-mode
      :ensure t
      :pin melpa
      :commands ido-vertical-mode)

[pierre-rouleau]

Well... I'v seen the problem occur (on Emacs 26.3) without ido-vertical-mode involved. I also have smex and ido-grid-mode active. More investigation is required to identify the culprit.
Any suggestions as to where I should be looking?

[pierre-rouleau]

Update: the issue I had was related to the order of execution. In my code ido-mode was not always set before the activation of the ido-vertical-mode. I fixed that and I have not yet run into the issue.

[pierre-rouleau]

My PEL system allows using ido-vertical-mode as well as other completion modes for Ido (standard, grid-mode) and other engines (ivy, helm). They can be selected by customization and commands exist to select them during a session. That helps testing the capabilities of various engines and use what best suits the task at hand. SO far my testing with ido-vertical-mode has shown no issue.