image-mode and pdf-tools conflict

[Ambrevar]

Depending on the load order, one mode takes precedence over the other which makes the latter unusable.

This might have to do with an inheritance problem.
Bug was reported upstream: politza/pdf-tools#324

[jojojames]

I don't use pdf-tools so won't be able to look at it directly.

I'm curious what the minor map alist looks like before/after you normalize keymaps?

(evil-normalize-keymaps)

evil-mode-map-alist <----------

[Ambrevar]

The before/after keymaps are the same.
Let me know if you want a dump.

A first glance at the problem reveals that

• doc-view and image-mode suffer from the same conflict.
• image-mode-map contains quite a few "remap". This could be the very root of the issue.

[Ambrevar]

By the way since doc-view is also concerned, you should be able to reproduce :)

[Ambrevar]

Some first experiments:

• The conflict happens in any state, Emacs state included.

• Emacs without evil is fine.

• I don't think it has anything to do with remap as j is not a remapped
  binding. I am not sure though.

• If doc-view / pdf-view maps are set first, then everything is OK.

• If image-mode map is set first, then the last binding will override the rest.

I tried using that result over the loading process of evil-collection to get
doc-view and image-mode to work but it did not. There must be something else.

Initial setup:

(require 'evil)
(evil-mode 1)

Some tests:

;;; Issue: doc-view overrides image-mode.

(evil-set-initial-state 'image-mode 'motion)
(evil-define-key 'motion image-mode-map "j" 'message-news)
(find-file "bar.png")

(evil-set-initial-state 'doc-view-mode 'motion)
(evil-define-key 'motion doc-view-mode-map "j" 'emacs-version)
(find-file "foo.odt")

;;; Change order.
;;; Issue: None.

(evil-set-initial-state 'doc-view-mode 'motion)
(evil-define-key 'motion doc-view-mode-map "j" 'emacs-version)
(find-file "foo.odt")

(evil-set-initial-state 'image-mode 'motion)
(evil-define-key 'motion image-mode-map "j" 'message-news)
(find-file "bar.png")

;;; Emacs state suffers from the same conflict.
;;; Issue: doc-view overrides image-mode.

(evil-set-initial-state 'image-mode 'emacs)
(evil-define-key 'emacs image-mode-map "j" 'message-news)
(find-file "bar.png")

(evil-define-key 'emacs doc-view-mode-map "j" 'emacs-version)
(find-file "foo.odt")

;;; Emacs without Evil is fine.
;;; Issue: None.

(find-file "bar.png")
(define-key image-mode-map "j" 'message-news)
(find-file "foo.odt")
(define-key doc-view-mode-map "j" 'emacs-version)

;;; Issue: image-mode binding is undefined

(evil-set-initial-state 'image-mode 'emacs)
(find-file "bar.png")
(evil-define-key 'emacs doc-view-mode-map "j" 'emacs-version)
(find-file "foo.odt")
(evil-define-key 'emacs image-mode-map "j" 'message-news)

;;; Issue: Both bindings are undefined.

(evil-set-initial-state 'image-mode 'emacs)
(find-file "bar.png")
(find-file "foo.odt")
(evil-define-key 'emacs doc-view-mode-map "j" 'emacs-version)
(evil-define-key 'emacs image-mode-map "j" 'message-news)

;;; The starred functions trigger the same issue.
;;; Issue: doc-view overrides image-mode

(evil-set-initial-state 'image-mode 'emacs)
(require 'image-mode)
(require 'doc-view)
(evil-define-key* 'emacs image-mode-map "j" 'message-news)
(evil-define-key* 'emacs doc-view-mode-map "j" 'emacs-version)
(find-file "bar.png")
(find-file "foo.odt")

[Ambrevar]

emacs-evil/evil#982 fixes this.

[Ambrevar]

Special thanks to @noctuid, this was a hard one.