Fix ambiguity in nil DST flag
commit0bec064454adac2bdff04a11bbdfaa79aa4ce052
authorPaul Eggert <eggert@cs.ucla.edu>
Fri, 21 Sep 2018 21:24:42 +0000 (21 14:24 -0700)
committerPaul Eggert <eggert@cs.ucla.edu>
Fri, 21 Sep 2018 21:25:19 +0000 (21 14:25 -0700)
treeab85b4e46d2ab44dd3d02b85a5a540470842e470
parent167274d44f1ccaee65a5b68e15c3ed79a53447d1
Fix ambiguity in nil DST flag

Formerly nil meant both that DST was not in effect and that
the DST flag was unknown, and different functions interpreted
the flag differently.  Now the meaning is consistently nil for
DST not in effect, and -1 for DST flag not known.
* doc/lispref/os.texi (Time Conversion): The DST slot is
now three-valued, not two-.
* doc/misc/emacs-mime.texi (time-date): Adjust to new behavior.
* etc/NEWS: Mention this.
* lisp/calendar/parse-time.el (parse-time-string):
* src/editfns.c (Fdecode_time):
Return -1 for unknown DST flag.
* test/lisp/calendar/parse-time-tests.el (parse-time-tests):
Adjust tests to match new behavior, and add a new
test for nil vs -1.
doc/lispref/os.texi
doc/misc/emacs-mime.texi
etc/NEWS
lisp/calendar/parse-time.el
src/editfns.c
test/lisp/calendar/parse-time-tests.el