Fix timestamp bug when write-region appends nothing.

* fileio.c (Fwrite_region): When neither O_EXCL nor O_TRUNC is used,
the file's time stamp doesn't change if Emacs happens to write nothing
to the file, and on a buggy file system this could cause Emacs to
incorrectly infer that the file system doesn't have the bug.
Avoid this problem by inhibiting the inference in this case.

Fixes: debbugs:13149

1 files changed, 9 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 9682da24235..b4c3195973c 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2013-02-01  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Fix timestamp bug when write-region appends nothing (Bug#13149).
+        * fileio.c (Fwrite_region): When neither O_EXCL nor O_TRUNC is used,
+        the file's time stamp doesn't change if Emacs happens to write nothing
+        to the file, and on a buggy file system this could cause Emacs to
+        incorrectly infer that the file system doesn't have the bug.
+        Avoid this problem by inhibiting the inference in this case.
+
 2013-02-01  Dmitry Antipov  <dmantipov@yandex.ru>
 
         * window.h (struct window): Convert base_line_number, base_line_pos