[Emacs-diffs] master b31d359 1/2: CC Mode: Stop Font Lock forcing fontification from BOL. Fixes debbugs#19669.

[Alan Mackenzie]

branch: master
commit b31d359d182eb252a11f0468a7dc1ee1eafb28e9
Author: Alan Mackenzie <address@hidden>
Commit: Alan Mackenzie <address@hidden>

    CC Mode: Stop Font Lock forcing fontification from BOL.  Fixes 
debbugs#19669.
    
    cc-mode.el (c-font-lock-init): Setq font-lock-extend-region-functions to
    nil.
---
 lisp/ChangeLog            |    8 ++++++++
 lisp/progmodes/cc-mode.el |    8 ++++++++
 2 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 7060258..38bb8af 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,11 @@
+2015-02-01  Alan Mackenzie  <address@hidden>
+
+       CC Mode: Stop Font Lock forcing fontification from BOL.  Fixes
+       debbugs#19669.
+
+       * progmodes/cc-mode.el (c-font-lock-init): Setq
+       font-lock-extend-region-functions to nil.
+
 2015-04-06  Fabián Ezequiel Gallina  <address@hidden>
 
        python.el: Do not break IPython magic completions.  (Bug#19736)
diff --git a/lisp/progmodes/cc-mode.el b/lisp/progmodes/cc-mode.el
index 42ee140..d88fe70 100644
--- a/lisp/progmodes/cc-mode.el
+++ b/lisp/progmodes/cc-mode.el
@@ -1302,6 +1302,14 @@ This function is called from `c-common-init', once per 
mode initialization."
          (font-lock-mark-block-function
           . c-mark-function)))
 
+  ;; Prevent `font-lock-default-fontify-region' extending the region it will
+  ;; fontify to whole lines by removing `font-lock-extend-region-whole-lines'
+  ;; (and, coincidentally, `font-lock-extend-region-multiline' (which we do
+  ;; not need)) from `font-lock-extend-region-functions'.  (Emacs only).  This
+  ;; fixes Emacs bug #19669.
+  (when (boundp 'font-lock-extend-region-functions)
+    (setq font-lock-extend-region-functions nil))
+
   (make-local-variable 'font-lock-fontify-region-function)
   (setq font-lock-fontify-region-function 'c-font-lock-fontify-region)