CC Mode: Fix wrong value of comment-start-skip, fixing half of bug #41952

Also add functions to enable correct use of CC Mode's filling functionality
from major modes which don't initialize CC Mode fully.  These modes are
currently js-mode and mhtml-mode.

* lisp/progmodes/cc-langs.el (comment-start-skip): Replace "\\(" by "\\(?:" so
that (match-end 1) isn't falsely taken to be the start of the comment.

* lisp/progmodes/cc-engine.el (c-foreign-truncate-lit-pos-cache)
(c-foreign-init-lit-pos-cache): New functions.

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index 1977eadb5c61fbe061121de5e6f5e87f922ea1c5..fec1065fe167e3e90ecd45e1dad5adf1446421f4 100644 (file)
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -3186,6 +3186,24 @@ comment at the start of cc-engine.el for more info."
        c-semi-near-cache-limit (min c-semi-near-cache-limit pos)
        c-full-near-cache-limit (min c-full-near-cache-limit pos)))
 
+(defun c-foreign-truncate-lit-pos-cache (beg _end)
+  "Truncate CC Mode's literal cache.
+
+This function should be added to the `before-change-functions'
+hook by major modes that use CC Mode's filling functionality
+without initializing CC Mode.  Currently (2020-06) these are
+js-mode and mhtml-mode."
+  (c-truncate-lit-pos-cache beg))
+
+(defun c-foreign-init-lit-pos-cache ()
+  "Initialize CC Mode's literal cache.
+
+This function should be called from the mode functions of major
+modes which use CC Mode's filling functionality without
+initializing CC Mode.  Currently (2020-06) these are js-mode and
+mhtml-mode."
+  (c-truncate-lit-pos-cache 1))
+
 \f
 ;; A system for finding noteworthy parens before the point.
 

diff --git a/lisp/progmodes/cc-langs.el b/lisp/progmodes/cc-langs.el
index 814a85c72a6dc9bd7db54bb5dee5b6aeb7fbf911..b77bf3303b6b95a9392f3a45554de79757f1521f 100644 (file)
--- a/lisp/progmodes/cc-langs.el
+++ b/lisp/progmodes/cc-langs.el
@@ -1769,7 +1769,7 @@ ender."
 `comment-start-skip' is initialized from this."
   ;; Default: Allow the last char of the comment starter(s) to be
   ;; repeated, then allow any amount of horizontal whitespace.
-  t (concat "\\("
+  t (concat "\\(?:"
            (c-concat-separated
             (mapcar (lambda (cs)
                       (when cs