Fix bugs in file timestamp newness comparisons.

* fileio.c (Ffile_newer_than_file_p):
* lread.c (Fload): Use full timestamp resolution of files,
not just the 1-second resolution, so that files that are only
slightly newer still count as newer.
* fileio.c (Ffile_newer_than_file_p): Don't assume file
timestamps fit in 'int'; this fixes a Y2038 bug on most hosts.

3 files changed, 19 insertions, 8 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 87e92170261..5433c2ff831 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,16 @@
+2012-07-04  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Fix bugs in file timestamp newness comparisons.
+        * fileio.c (Ffile_newer_than_file_p):
+        * lread.c (Fload): Use full timestamp resolution of files,
+        not just the 1-second resolution, so that files that are only
+        slightly newer still count as newer.
+        * fileio.c (Ffile_newer_than_file_p): Don't assume file
+        timestamps fit in 'int'; this fixes a Y2038 bug on most hosts.
+
 2012-07-03  Paul Eggert  <eggert@cs.ucla.edu>
 
+
         * fileio.c: Improve handling of file time marker.  (Bug#11852)
         (special_mtime): New function.
         (Finsert_file_contents, Fverify_visited_file_modtime):
diff --git a/src/fileio.c b/src/fileio.c
index 6c3a3b206e8..1dadd06c283 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -3079,8 +3079,7 @@ otherwise, if FILE2 does not exist, the answer is t.  */)
   (Lisp_Object file1, Lisp_Object file2)
 {
   Lisp_Object absname1, absname2;
-  struct stat st;
-  int mtime1;
+  struct stat st1, st2;
   Lisp_Object handler;
   struct gcpro gcpro1, gcpro2;
 
@@ -3106,15 +3105,14 @@ otherwise, if FILE2 does not exist, the answer is t.  */)
   absname2 = ENCODE_FILE (absname2);
   UNGCPRO;
 
-  if (stat (SSDATA (absname1), &st) < 0)
+  if (stat (SSDATA (absname1), &st1) < 0)
     return Qnil;
 
-  mtime1 = st.st_mtime;
-
-  if (stat (SSDATA (absname2), &st) < 0)
+  if (stat (SSDATA (absname2), &st2) < 0)
     return Qt;
 
-  return (mtime1 > st.st_mtime) ? Qt : Qnil;
+  return (EMACS_TIME_GT (get_stat_mtime (&st1), get_stat_mtime (&st2))
+          ? Qt : Qnil);
 }
 
 #ifndef READ_BUF_SIZE
diff --git a/src/lread.c b/src/lread.c
index 7a0b20880e9..1e496bf9742 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -26,6 +26,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <errno.h>
 #include <limits.h>     /* For CHAR_BIT.  */
 #include <setjmp.h>
+#include <stat-time.h>
 #include "lisp.h"
 #include "intervals.h"
 #include "character.h"
@@ -1214,7 +1215,8 @@ Return t if the file exists and loads successfully.  */)
               SSET (efound, SBYTES (efound) - 1, 'c');
             }
 
-          if (result == 0 && s1.st_mtime < s2.st_mtime)
+          if (result == 0
+              && EMACS_TIME_LT (get_stat_mtime (&s1), get_stat_mtime (&s2)))
             {
               /* Make the progress messages mention that source is newer.  */
               newer = 1;