From ad5e350ab764f3a420d29f24ab3222f671b2e8c0 Mon Sep 17 00:00:00 2001
From: Alan Mackenzie <acm@muc.de>
Date: Mon, 10 Feb 2020 21:20:12 +0000
Subject: [PATCH] c-end-of-macro: Handle block coment lines with unescaped NLs
 correctly

* lisp/progmodes/cc-langs.el (c-last-open-c-comment-start-on-line-re): Make
obsolete, and supersede by ...
(c-open-c-comment-on-logical-line-re): New language variable.

* lisp/progmodes/cc-engine.el (c-end-of-macro): Inside macros, handle
multiline block comments whose line ends are not escaped correctly.
---
 lisp/progmodes/cc-engine.el | 17 ++++++++++-------
 lisp/progmodes/cc-langs.el  | 19 ++++++++++++++++++-
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index c3cd31fdd00..23fb1effdd4 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -388,14 +388,17 @@ comment at the start of cc-engine.el for more info."
 			 (forward-char)
 			 t)))
 	      (let ((cand-EOM (point)))
-		(if (and c-last-open-c-comment-start-on-line-re
+		(if (and c-open-c-comment-on-logical-line-re
 			 (re-search-backward
-			  c-last-open-c-comment-start-on-line-re
-			  (c-point 'bol) t))
-		    (progn
-		      (goto-char (match-beginning 1))
-		      (and (c-forward-single-comment)
-			   (> (point) cand-EOM)))
+			  c-open-c-comment-on-logical-line-re
+			  nil t)
+			 (match-beginning 1)
+			 (progn
+			   (goto-char (match-beginning 1))
+			   (and (c-forward-single-comment)
+				(> (point) cand-EOM))))
+		    t
+		  (goto-char cand-EOM)
 		  nil)))))
 
       (when (and (car c-macro-cache)
diff --git a/lisp/progmodes/cc-langs.el b/lisp/progmodes/cc-langs.el
index 8d0ade70f36..667561719cb 100644
--- a/lisp/progmodes/cc-langs.el
+++ b/lisp/progmodes/cc-langs.el
@@ -1707,7 +1707,10 @@ ender."
 	       (c-lang-const c-last-c-comment-end-on-line-re))
 
 (c-lang-defconst c-last-open-c-comment-start-on-line-re
-  "Regexp which matches the last block comment start on the
+  "Do NOT use this constant any more.  Instead use
+`c-open-c-comment-on-logical-line-re' (2020-02-10).
+
+Regexp which matches the last block comment start on the
 current ine, if any, or nil in those languages without block
 comments.  When a match is found, submatch 1 contains the comment
 starter."
@@ -1715,6 +1718,20 @@ starter."
   awk nil)
 (c-lang-defvar c-last-open-c-comment-start-on-line-re
 	       (c-lang-const c-last-open-c-comment-start-on-line-re))
+(make-obsolete-variable 'c-last-open-c-comment-start-on-line-re
+			'c-open-c-comment-on-logical-line-re
+			"5.35")
+
+(c-lang-defconst c-open-c-comment-on-logical-line-re
+  "Regexp which matches an open block comment on the current logical line.
+It is intended for searching backwards from the end of a line.
+Such a search will stop at the first encountered non-escaped
+newline or open block comment.  If the comment is found, submatch
+1 contains the comment starter."
+t "[^\\\n][\r\n]\\|\\(/\\*\\)\\([^*]\\|\\*+\\([^*/]\\|$\\)\\)*$"
+awk nil)
+(c-lang-defvar c-open-c-comment-on-logical-line-re
+	       (c-lang-const c-open-c-comment-on-logical-line-re))
 
 (c-lang-defconst c-literal-start-regexp
   ;; Regexp to match the start of comments and string literals.
-- 
2.39.5