emacs-27 ad5e350: c-end-of-macro: Handle block coment lines with unescaped NLs correctly

[Alan Mackenzie]

branch: emacs-27
commit ad5e350ab764f3a420d29f24ab3222f671b2e8c0
Author: Alan Mackenzie <address@hidden>
Commit: Alan Mackenzie <address@hidden>

    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 c3cd31f..23fb1ef 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 8d0ade7..6675617 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.