Special handling of the `custom-enabled-themes' custom variable.

* lisp/custom.el (custom--inhibit-theme-enable): Make it affect only
custom-theme-set-variables and custom-theme-set-faces.
(provide-theme): Ignore custom--inhibit-theme-enable.
(load-theme): Enable the theme explicitly if NO-ENABLE is non-nil.
(custom-enabling-themes): Delete variable.
(enable-theme): Accept only loaded themes as arguments.  Ignore
the special custom-enabled-themes variable.
(custom-enabled-themes): Forbid themes from setting this.
Eliminate use of custom-enabling-themes.
(custom-push-theme): Quote "changed" custom var entry.

lisp/ChangeLog

@@ -1,6 +1,15 @@
-2011-03-21  Chong Yidong  <cyd@stupidchicken.com>
+2011-03-22  Chong Yidong  <cyd@stupidchicken.com>
 
-	* custom.el (custom-push-theme): Quote "changed" custom var entry.
+	* custom.el (custom--inhibit-theme-enable): Make it affect only
+	custom-theme-set-variables and custom-theme-set-faces.
+	(provide-theme): Ignore custom--inhibit-theme-enable.
+	(load-theme): Enable the theme explicitly if NO-ENABLE is non-nil.
+	(custom-enabling-themes): Delete variable.
+	(enable-theme): Accept only loaded themes as arguments.  Ignore
+	the special custom-enabled-themes variable.
+	(custom-enabled-themes): Forbid themes from setting this.
+	Eliminate use of custom-enabling-themes.
+	(custom-push-theme): Quote "changed" custom var entry.
 
 2011-03-21  Leo Liu  <sdl.web@gmail.com>
 

lisp/custom.el

@@ -1081,10 +1081,10 @@ name."
   :version "24.1")
 
 (defvar custom--inhibit-theme-enable nil
-  "If non-nil, loading a theme does not enable it.
-This internal variable is set by `load-theme' when its NO-ENABLE
-argument is non-nil, and it affects `custom-theme-set-variables',
-`custom-theme-set-faces', and `provide-theme'." )
+  "Whether the custom-theme-set-* functions act immediately.
+If nil, `custom-theme-set-variables' and `custom-theme-set-faces'
+change the current values of the given variable or face.  If
+non-nil, they just make a record of the theme settings.")
 
 (defun provide-theme (theme)
   "Indicate that this file provides THEME.
@@ -1094,15 +1094,7 @@ property `theme-feature' (which is usually a symbol created by
   (unless (custom-theme-name-valid-p theme)
     (error "Custom theme cannot be named %S" theme))
   (custom-check-theme theme)
-  (provide (get theme 'theme-feature))
-  (unless custom--inhibit-theme-enable
-    ;; By default, loading a theme also enables it.
-    (push theme custom-enabled-themes)
-    ;; `user' must always be the highest-precedence enabled theme.
-    ;; Make that remain true.  (This has the effect of making user
-    ;; settings override the ones just loaded, too.)
-    (let ((custom-enabling-themes t))
-      (enable-theme 'user))))
+  (provide (get theme 'theme-feature)))
 
 (defcustom custom-safe-themes '(default)
   "List of themes that are considered safe to load.
@@ -1154,9 +1146,11 @@ Return t if THEME was successfully loaded, nil otherwise."
 			    (expand-file-name "themes/" data-directory)))
 		(member hash custom-safe-themes)
 		(custom-theme-load-confirm hash))
-	(let ((custom--inhibit-theme-enable no-enable))
-	  (eval-buffer)
-	  t)))))
+	(let ((custom--inhibit-theme-enable t))
+	  (eval-buffer))
+	(unless no-enable
+	  (enable-theme theme))
+	t))))
 
 (defun custom-theme-load-confirm (hash)
   "Query the user about loading a Custom theme that may not be safe.
@@ -1235,68 +1229,70 @@ NAME should be a symbol."
 
 ;;; Enabling and disabling loaded themes.
 
-(defvar custom-enabling-themes nil)
-
 (defun enable-theme (theme)
   "Reenable all variable and face settings defined by THEME.
-The newly enabled theme gets the highest precedence (after `user').
-If it is already enabled, just give it highest precedence (after `user').
-
-If THEME does not specify any theme settings, this tries to load
-the theme from its theme file, by calling `load-theme'."
+THEME should be either `user', or a theme loaded via `load-theme'.
+After this function completes, THEME will have the highest
+precedence (after `user')."
   (interactive (list (intern
 		      (completing-read
 		       "Enable custom theme: "
-		       obarray (lambda (sym) (get sym 'theme-settings))))))
+		       obarray (lambda (sym) (get sym 'theme-settings)) t))))
   (if (not (custom-theme-p theme))
-      (load-theme theme)
-    ;; This could use a bit of optimization -- cyd
-    (let ((settings (get theme 'theme-settings)))
-      (dolist (s settings)
-	(let* ((prop (car s))
-	       (symbol (cadr s))
-	       (spec-list (get symbol prop)))
-	  (put symbol prop (cons (cddr s) (assq-delete-all theme spec-list)))
-	  (if (eq prop 'theme-value)
-	      (custom-theme-recalc-variable symbol)
-	    (custom-theme-recalc-face symbol)))))
-    (unless (eq theme 'user)
-      (setq custom-enabled-themes
-	    (cons theme (delq theme custom-enabled-themes)))
-      (unless custom-enabling-themes
-	(enable-theme 'user)))))
+      (error "Undefined Custom theme %s" theme))
+  (let ((settings (get theme 'theme-settings)))
+    ;; Loop through theme settings, recalculating vars/faces.
+    (dolist (s settings)
+      (let* ((prop (car s))
+	     (symbol (cadr s))
+	     (spec-list (get symbol prop)))
+	(put symbol prop (cons (cddr s) (assq-delete-all theme spec-list)))
+	(cond
+	 ((eq prop 'theme-face)
+	  (custom-theme-recalc-face symbol))
+	 ((eq prop 'theme-value)
+	  ;; Don't change `custom-enabled-themes'; that's special.
+	  (unless (eq symbol 'custom-enabled-themes)
+	    (custom-theme-recalc-variable symbol)))))))
+  (unless (eq theme 'user)
+    (setq custom-enabled-themes
+	  (cons theme (delq theme custom-enabled-themes)))
+    ;; Give the `user' theme the highest priority.
+    (enable-theme 'user)))
 
 (defcustom custom-enabled-themes nil
   "List of enabled Custom Themes, highest precedence first.
+This list does not include the `user' theme, which is set by
+Customize and always takes precedence over other Custom Themes.
 
-This does not include the `user' theme, which is set by Customize,
-and always takes precedence over other Custom Themes."
+This variable cannot be defined inside a Custom theme; there, it
+is simply ignored."
   :group 'customize
   :type  '(repeat symbol)
   :set-after '(custom-theme-directory custom-theme-load-path
 				      custom-safe-themes)
   :risky t
   :set (lambda (symbol themes)
-	 ;; Avoid an infinite loop when custom-enabled-themes is
-	 ;; defined in a theme (e.g. `user').  Enabling the theme sets
-	 ;; custom-enabled-themes, which enables the theme...
-	 (unless custom-enabling-themes
-	   (let ((custom-enabling-themes t) failures)
-	     (setq themes (delq 'user (delete-dups themes)))
-	     (if (boundp symbol)
-		 (dolist (theme (symbol-value symbol))
-		   (if (not (memq theme themes))
-		       (disable-theme theme))))
-	     (dolist (theme (reverse themes))
-	       (condition-case nil
-		   (enable-theme theme)
-		 (error (progn (push theme failures)
-			       (setq themes (delq theme themes))))))
-	     (enable-theme 'user)
-	     (custom-set-default symbol themes)
-	     (if failures
-		 (message "Failed to enable themes: %s"
-			  (mapconcat 'symbol-name failures " ")))))))
+	 (let (failures)
+	   (setq themes (delq 'user (delete-dups themes)))
+	   ;; Disable all themes not in THEMES.
+	   (if (boundp symbol)
+	       (dolist (theme (symbol-value symbol))
+		 (if (not (memq theme themes))
+		     (disable-theme theme))))
+	   ;; Call `enable-theme' or `load-theme' on each of THEMES.
+	   (dolist (theme (reverse themes))
+	     (condition-case nil
+		 (if (custom-theme-p theme)
+		     (enable-theme theme)
+		   (load-theme theme))
+	       (error (setq failures (cons theme failures)
+			    themes (delq theme themes)))))
+	   (enable-theme 'user)
+	   (custom-set-default symbol themes)
+	   (if failures
+	       (message "Failed to enable theme: %s"
+			(mapconcat 'symbol-name failures ", "))))))
 
 (defsubst custom-theme-enabled-p (theme)
   "Return non-nil if THEME is enabled."