Fix (date-to-time "2021-12-04")

This should complete the fix for Bug#52209.
* lisp/calendar/time-date.el (date-to-time): Apply
decoded-time-set-defaults only to the output of (parse-time-string
date), and only when the output has a year (to avoid confusion
when dates lack years).  There is no point applying it after
timezone-make-date-arpa-standard since the latter fills in all the
blanks.  And the former code mistakenly called encode-time on an
already-encoded time.  This goes back to the code a couple of days
ago, except with changed behavior (to fix Bug#52209) only when
timezone-make-date-arpa-standard is not called.
* test/lisp/calendar/time-date-tests.el (test-date-to-time)
(test-days-between): New tests.

diff --git a/doc/lispref/os.texi b/doc/lispref/os.texi
index e420644cd81577c7abd9d6e0a88a4d25960af593..b4efc44b039c8c91b55c1992b829dc7df0e4d0bc 100644 (file)
--- a/doc/lispref/os.texi
+++ b/doc/lispref/os.texi
@@ -1724,7 +1724,8 @@ This function parses the time-string @var{string} and returns the
 corresponding Lisp timestamp.  The argument @var{string} should represent
 a date-time, and should be in one of the forms recognized by
 @code{parse-time-string} (see below).  This function assumes Universal
-Time if @var{string} lacks explicit time zone information.
+Time if @var{string} lacks explicit time zone information,
+and assumes earliest values if @var{string} lacks month, day, or time.
 The operating system limits the range of time and zone values.
 @end defun
 

diff --git a/etc/NEWS b/etc/NEWS
index ac1787d7f80faa703098ed6a29c5605ad1b81317..2b4eaaf8a1a2f938d0523728fa8a0e1928fde555 100644 (file)
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1084,6 +1084,10 @@ cookies set by web pages on disk.
 ** New variable 'help-buffer-under-preparation'.
 This variable is bound to t during the preparation of a "*Help*" buffer.
 
++++
+** 'date-to-time' now assumes earliest values if its argument lacks
+month, day, or time.  For example, (date-to-time "2021-12-04") now
+assumes a time of 00:00 instead of signaling an error.
 \f
 * Changes in Emacs 29.1 on Non-Free Operating Systems
 

diff --git a/lisp/calendar/time-date.el b/lisp/calendar/time-date.el
index 8a6ee0f270257d63d4d34db1f1318bfd2f79e70d..37a16d3b98c8be22a2dcb8301f008afc3bd4eb68 100644 (file)
--- a/lisp/calendar/time-date.el
+++ b/lisp/calendar/time-date.el
@@ -153,28 +153,22 @@ it is assumed that PICO was omitted and should be treated as zero."
   "Parse a string DATE that represents a date-time and return a time value.
 DATE should be in one of the forms recognized by `parse-time-string'.
 If DATE lacks timezone information, GMT is assumed."
-  ;; Pass the result of parsing through decoded-time-set-defaults
-  ;; because encode-time signals if HH:MM:SS are not filled in.
-  (encode-time
-    (decoded-time-set-defaults
-      (condition-case err
-          (let ((time (parse-time-string date)))
-            (prog1 time
-              ;; Cause an error if data `parse-time-string' returns is invalid.
-              (setq time (encode-time time))))
-        (error
-         (let ((overflow-error '(error "Specified time is not representable")))
-           (if (or (equal err overflow-error)
-                   ;; timezone-make-date-arpa-standard misbehaves if
-                   ;; not given at least HH:MM as part of the date.
-                   (not (string-match ":" date)))
-               (signal (car err) (cdr err))
-             (condition-case err
-                 (parse-time-string (timezone-make-date-arpa-standard date))
-               (error
-                (if (equal err overflow-error)
-                    (signal (car err) (cdr err))
-                  (error "Invalid date: %s" date)))))))))))
+  (condition-case err
+      (let ((parsed (parse-time-string date)))
+       (when (decoded-time-year parsed)
+         (decoded-time-set-defaults parsed))
+       (encode-time parsed))
+    (error
+     (let ((overflow-error '(error "Specified time is not representable")))
+       (if (equal err overflow-error)
+          (signal (car err) (cdr err))
+        (condition-case err
+            (encode-time (parse-time-string
+                          (timezone-make-date-arpa-standard date)))
+          (error
+           (if (equal err overflow-error)
+               (signal (car err) (cdr err))
+             (error "Invalid date: %s" date)))))))))
 
 ;;;###autoload
 (defalias 'time-to-seconds 'float-time)

diff --git a/test/lisp/calendar/time-date-tests.el b/test/lisp/calendar/time-date-tests.el
index 4568947c0b3523f4c74f7b33d844842cd5b6e92e..d5269804ad22cfda58d310f440c04c8a9da4e0f7 100644 (file)
--- a/test/lisp/calendar/time-date-tests.el
+++ b/test/lisp/calendar/time-date-tests.el
@@ -41,6 +41,13 @@
                    (encode-time-value 1 2 3 4 3))
                  '(1 2 3 4))))
 
+(ert-deftest test-date-to-time ()
+  (should (equal (format-time-string "%F %T" (date-to-time "2021-12-04"))
+                 "2021-12-04 00:00:00")))
+
+(ert-deftest test-days-between ()
+  (should (equal (days-between "2021-10-22" "2020-09-29") 388)))
+
 (ert-deftest test-leap-year ()
   (should-not (date-leap-year-p 1999))
   (should-not (date-leap-year-p 1900))