Default to 1970 in decoded-time-set-defaults

* lisp/calendar/time-date.el (decoded-time-set-defaults): Set an
unspecified year field to 1970, as promised in the docstring, and to
ensure it's representable on all systems (bug#48298).

diff --git a/lisp/calendar/time-date.el b/lisp/calendar/time-date.el
index 2df57a3c33dbcda640d168dd2f1228b594887104..1c169b78fd61dfea5fc5a630be6349e1e3d63e8d 100644 (file)
--- a/lisp/calendar/time-date.el
+++ b/lisp/calendar/time-date.el
@@ -525,6 +525,8 @@ changes in daylight saving time are not taken into account."
 (defun decoded-time-set-defaults (time &optional default-zone)
   "Set any nil values in `decoded-time' TIME to default values.
 The default value is based on January 1st, 1970 at midnight.
+This year is used to guarantee portability; see Info
+node `(elisp) Time of Day'.
 
 TIME is modified and returned."
   (unless (decoded-time-second time)
@@ -539,7 +541,7 @@ TIME is modified and returned."
   (unless (decoded-time-month time)
     (setf (decoded-time-month time) 1))
   (unless (decoded-time-year time)
-    (setf (decoded-time-year time) 0))
+    (setf (decoded-time-year time) 1970))
 
   ;; When we don't have a time zone, default to DEFAULT-ZONE without
   ;; DST if DEFAULT-ZONE if given, and to unknown DST otherwise.