line-number: fix backward compatibility

There was an error in `linum-on` when `dotspacemacs-line-numbers` was set to
`'relative`.

- new function `spacemacs//linum-backward-compabitility` to test for old
supported values.
- Use an :around advice for `linum-on` instead of redefining it.
- move linum init time config to `:init` section of `use-package`
- fix relative linum initialization by testing if `dotspacemacs-line-numbers` is
  a list first.

layers/+distributions/spacemacs-base/funcs.el

@@ -1034,12 +1034,32 @@ if prefix argument ARG is given, switch to it in an other, possibly new window."
   (when compilation-last-buffer
     (delete-windows-on compilation-last-buffer)))
 
+
+;; Line number
+
 (defun spacemacs/no-linum (&rest ignore)
   "Disable linum if current buffer."
   (when (or 'linum-mode global-linum-mode)
     (linum-mode 0)))
 
-(defun spacemacs/linum-update-window-scale-fix (win)
+(defun spacemacs/enable-line-numbers-p ()
+  "Return non-nil if line numbers should be enabled for current buffer.
+Decision is based on `dotspacemacs-line-numbers'."
+  (and dotspacemacs-line-numbers
+       (spacemacs//linum-current-buffer-is-not-special)
+       (or (spacemacs//linum-backward-compabitility)
+           (spacemacs//linum-curent-buffer-is-not-too-big)
+           ;; explicitly enabled buffers take priority over explicitly disabled
+           ;; ones
+           (or (spacemacs//linum-enabled-for-current-major-mode)
+               (not (spacemacs//linum-disabled-for-current-major-mode))))))
+
+(defun spacemacs//linum-on (origfunc &rest args)
+  "Advice function to improve `linum-on' function."
+  (when (spacemacs/enable-line-numbers-p)
+    (apply origfunc args)))
+
+(defun spacemacs//linum-update-window-scale-fix (win)
   "Fix linum for scaled text in the window WIN."
   (set-window-margins win
                       (ceiling (* (if (boundp 'text-scale-mode-step)
@@ -1048,6 +1068,14 @@ if prefix argument ARG is given, switch to it in an other, possibly new window."
                                   (if (car (window-margins))
                                       (car (window-margins)) 1)))))
 
+(defun spacemacs//linum-backward-compabitility ()
+  "Return non-nil if `dotspacemacs-line-numbers' has an old format and if
+`linum' should be enabled."
+  (and dotspacemacs-line-numbers
+       (not (listp dotspacemacs-line-numbers))
+       (or (eq dotspacemacs-line-numbers t)
+           (eq dotspacemacs-line-numbers 'relative))))
+
 (defun spacemacs//linum-current-buffer-is-not-special ()
   "Return non-nil if current buffer is not a special buffer."
   (not (string-match-p "\\*.*\\*" (buffer-name))))
@@ -1070,14 +1098,3 @@ if prefix argument ARG is given, switch to it in an other, possibly new window."
   (and (spacemacs/mplist-get dotspacemacs-line-numbers :disabled-for-modes)
        (memq major-mode (spacemacs/mplist-get dotspacemacs-line-numbers
                                               :disabled-for-modes))))
-
-(defun spacemacs/enable-line-numbers-p ()
-  "Return non-nil if line numbers should be enabled for current buffer.
-Decision is based on `dotspacemacs-line-numbers'."
-  (and dotspacemacs-line-numbers
-       (spacemacs//linum-current-buffer-is-not-special)
-       (spacemacs//linum-curent-buffer-is-not-too-big)
-       ;; explicitly enabled buffers take priority over explicitly disabled
-       ;; ones
-       (or (spacemacs//linum-enabled-for-current-major-mode)
-           (not (spacemacs//linum-disabled-for-current-major-mode)))))

layers/+distributions/spacemacs-base/packages.el

@@ -241,26 +241,24 @@
 
 (defun spacemacs-base/init-linum ()
   (use-package linum
+    :init
+    (progn
+      (setq linum-format "%4d")
+      (spacemacs|add-toggle line-numbers
+        :mode linum-mode
+        :documentation "Show the line numbers."
+        :evil-leader "tn")
+      (advice-add #'linum-update-window
+                  :after #'spacemacs//linum-update-window-scale-fix)
+      (advice-add #'linum-on
+                  :around #'spacemacs//linum-on))
     :config
     (progn
-      (if (or (eq dotspacemacs-line-numbers t)
-              (eq dotspacemacs-line-numbers 'relative))
-          (progn
-            (add-hook 'prog-mode-hook 'linum-mode)
-            (add-hook 'text-mode-hook 'linum-mode)))
-      (defun linum-on ()
-        "Overwrite the original `linum-on' function with a more selective one."
-        (when (spacemacs/enable-line-numbers-p)
-          (linum-mode)))
+      (when (spacemacs//linum-backward-compabitility)
+        (add-hook 'prog-mode-hook 'linum-mode)
+        (add-hook 'text-mode-hook 'linum-mode))
       (when dotspacemacs-line-numbers
-        (global-linum-mode))))
-  (setq linum-format "%4d")
-  (spacemacs|add-toggle line-numbers
-    :mode linum-mode
-    :documentation "Show the line numbers."
-    :evil-leader "tn")
-  (advice-add #'linum-update-window
-              :after #'spacemacs/linum-update-window-scale-fix))
+        (global-linum-mode)))))
 
 (defun spacemacs-base/init-occur-mode ()
   (evilified-state-evilify-map occur-mode-map

layers/+spacemacs/spacemacs-evil/packages.el

@@ -260,8 +260,9 @@
     :init
     (progn
       (when (or (eq dotspacemacs-line-numbers 'relative)
-                (car (spacemacs/mplist-get dotspacemacs-line-numbers
-                                           :relative)))
+                (and (listp dotspacemacs-line-numbers)
+                     (car (spacemacs/mplist-get dotspacemacs-line-numbers
+                                                :relative))))
         (add-hook 'spacemacs-post-user-config-hook 'linum-relative-on))
       (spacemacs/set-leader-keys "tr" 'spacemacs/linum-relative-toggle))
     :config