Fix an unlikely `copyright-find-copyright' problem

* lisp/emacs-lisp/copyright.el (copyright-find-copyright): Make
the copyright matcher more robust (bug#7179).

1 files changed, 10 insertions, 5 deletions

diff --git a/lisp/emacs-lisp/copyright.el b/lisp/emacs-lisp/copyright.el
index 6ba2e7804bb..d2e4891acee 100644
--- a/lisp/emacs-lisp/copyright.el
+++ b/lisp/emacs-lisp/copyright.el
@@ -144,11 +144,16 @@ This function sets the match-data that `copyright-update-year' uses."
   (with-demoted-errors "Can't update copyright: %s"
     ;; (1) Need the extra \\( \\) around copyright-regexp because we
     ;; goto (match-end 1) below. See note (2) below.
-    (copyright-re-search (concat "\\(" copyright-regexp
-                                 "\\)\\([ \t]*\n\\)?.*\\(?:"
-                                 copyright-names-regexp "\\)")
-                         (copyright-limit)
-                         t)))
+    (let ((regexp (concat "\\(" copyright-regexp
+                          "\\)\\([ \t]*\n\\)?.*\\(?:"
+                          copyright-names-regexp "\\)")))
+      (when (copyright-re-search regexp (copyright-limit) t)
+        ;; We may accidentally have landed in the middle of a
+        ;; copyright line, so re-perform the search without the
+        ;; search.  (Otherwise we may be inserting the new year in the
+        ;; middle of the list of years.)
+        (goto-char (match-beginning 0))
+        (copyright-re-search regexp nil t)))))
 
 (defun copyright-find-end ()
   "Possibly adjust the search performed by `copyright-find-copyright'.