Do not allow out-of-range character position in Fcompare_strings.

* src/fns.c (validate_subarray): Add prototype.
(Fcompare_substring): Use validate_subarray to check ranges.
Adjust comment to mention that the semantics was changed.  Also see
http://lists.gnu.org/archive/html/emacs-devel/2014-06/msg00447.html.
* lisp/files.el (dir-locals-find-file, file-relative-name):
* lisp/info.el (Info-complete-menu-item):
* lisp/minibuffer.el (completion-table-subvert): Prefer string-prefix-p
to compare-strings to avoid out-of-range errors.
* lisp/subr.el (string-prefix-p): Adjust to match strict range
checking in compare-strings.
* test/automated/fns-tests.el (fns-tests-compare-string): New test.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 9f676a6518d..fc47fbc8978 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,11 @@
+2014-06-25  Dmitry Antipov  <dmantipov@yandex.ru>
+
+        Do not allow out-of-range character position in Fcompare_strings.
+        * fns.c (validate_subarray): Add prototype.
+        (Fcompare_substring): Use validate_subarray to check ranges.
+        Adjust comment to mention that the semantics was changed.  Also see
+        http://lists.gnu.org/archive/html/emacs-devel/2014-06/msg00447.html.
+
 2014-06-24  Paul Eggert  <eggert@cs.ucla.edu>
 
         Be more consistent about the 'Qfoo' naming convention.