Check there is a font-lock specification before initial fontification.

3 files changed, 35 insertions, 16 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index a6783b87baa..a79b6307d16 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,16 @@
+2012-02-26  Alan Mackenzie  <acm@muc.de>
+
+        Check there is a font-lock specification before doing initial
+        fontification.
+
+        * font-core.el (font-lock-mode): Move the conditional from
+        :after-hook to font-lock-initial-fontify.
+        (font-lock-default-function): Move the check for a specification
+        to font-lock-spec-present.
+
+        * font-lock.el (font-lock-initial-fontify): call ...
+        (font-lock-spec-present): New function.
+
 2012-02-26  Jim Blandy  <jimb@red-bean.com>
 
         * progmodes/gdb-mi.el (gdb-mi-quote): New function.
diff --git a/lisp/font-core.el b/lisp/font-core.el
index 9b655319bc9..4a88d973913 100644
--- a/lisp/font-core.el
+++ b/lisp/font-core.el
@@ -138,7 +138,7 @@ The above is the default behavior of `font-lock-mode'; you may specify
 your own function which is called when `font-lock-mode' is toggled via
 `font-lock-function'. "
   nil nil nil
-  :after-hook (if font-lock-mode (font-lock-initial-fontify))
+  :after-hook (font-lock-initial-fontify)
   ;; Don't turn on Font Lock mode if we don't have a display (we're running a
   ;; batch job) or if the buffer is invisible (the name starts with a space).
   (when (or noninteractive (eq (aref (buffer-name) 0) ?\s))
@@ -192,13 +192,7 @@ this function onto `change-major-mode-hook'."
 
   ;; Only do hard work if the mode has specified stuff in
   ;; `font-lock-defaults'.
-  (when (or font-lock-defaults
-            (if (boundp 'font-lock-keywords) font-lock-keywords)
-            (and mode
-                 (boundp 'font-lock-set-defaults)
-                 font-lock-set-defaults
-                 font-lock-major-mode
-                 (not (eq font-lock-major-mode major-mode))))
+  (when (font-lock-spec-present mode)
     (font-lock-mode-internal mode)))
 
 (defun turn-on-font-lock ()
diff --git a/lisp/font-lock.el b/lisp/font-lock.el
index a65a2c94c7d..7750b30f096 100644
--- a/lisp/font-lock.el
+++ b/lisp/font-lock.el
@@ -629,17 +629,29 @@ Major/minor modes can set this variable if they know which option applies.")
   ;; Shut up the byte compiler.
   (defvar font-lock-face-attributes))   ; Obsolete but respected if set.
 
+(defun font-lock-spec-present (mode)
+  ;; Is there enough specification to do fontification at all?
+  (or font-lock-defaults
+      (if (boundp 'font-lock-keywords) font-lock-keywords)
+      (and mode
+           (boundp 'font-lock-set-defaults)
+           font-lock-set-defaults
+           font-lock-major-mode
+           (not (eq font-lock-major-mode major-mode)))))
+
 (defun font-lock-initial-fontify ()
   ;; The first fontification after turning the mode on.  This must
   ;;  only be called after the mode hooks have been run.
-  (let ((max-size (font-lock-value-in-major-mode font-lock-maximum-size)))
-    (cond (font-lock-fontified
-           nil)
-          ((or (null max-size) (> max-size (buffer-size)))
-           (font-lock-fontify-buffer))
-          (font-lock-verbose
-           (message "Fontifying %s...buffer size greater than font-lock-maximum-size"
-                    (buffer-name))))))
+  (when (and font-lock-mode
+             (font-lock-spec-present t))
+    (let ((max-size (font-lock-value-in-major-mode font-lock-maximum-size)))
+      (cond (font-lock-fontified
+             nil)
+            ((or (null max-size) (> max-size (buffer-size)))
+             (font-lock-fontify-buffer))
+            (font-lock-verbose
+             (message "Fontifying %s...buffer size greater than font-lock-maximum-size"
+                      (buffer-name)))))))
 
 (defun font-lock-mode-internal (arg)
   ;; Turn on Font Lock mode.