Subject: [PATCH v4 0/4] approxidate: tweak special date formats

From: Tuomas Ahola <[email-masked]>
Date: Sat, 16 May 2026 18:15:36 +0300

The approxidate system is an endless source of absurdities.  Let's make the
usual "eh, that's crazy, let's do better with this input" type of fix[1], and
tweak some sharp edge cases, including one noticed by Linus back in 2006[2].

After this series, "tea" and "noon" will work predictably with all kinds of
date formats (today, yesterday, last Friday, January 5th, one year ago
yesterday...) regardless of the current time of day.

More importantly, approxidate is taught about "today", meaning by default
the last midnight, as discussed in the RFC thread.[3]

Links:
  1. https://lore.kernel.org/git/[email-masked]/
  2. https://lore.kernel.org/git/[email-masked]/
  3. https://lore.kernel.org/git/[email-masked]/

Tuomas Ahola (4):
  approxidate: make "today" wrap to midnight
  t0006: add support for approxidate test date adjustment
  approxidate: make "specials" respect fixed day-of-month
  approxidate: use deferred mday adjustments for "specials"

 Documentation/rev-list-options.adoc |  3 +-
 date.c                              | 45 ++++++++++++++++++++++-------
 t/t0006-date.sh                     | 43 ++++++++++++++++++++++++++-
 3 files changed, 79 insertions(+), 12 deletions(-)

Intervall-diff mot v3:
-:  ---------- > 1:  86bcb70ac2 approxidate: make "today" wrap to midnight
1:  7ea9c9967b = 2:  9863f359a1 t0006: add support for approxidate test date adjustment
2:  3a21727dbe < -:  ---------- approxidate: alias "today" to "now"
3:  d1992d23d0 = 3:  830de02f74 approxidate: make "specials" respect fixed day-of-month
4:  0b1a10305c ! 4:  d33195dc91 approxidate: use deferred mday adjustments for "specials"
    @@ Commit message
         field for deferred date adjustments which can be easily reverted, so
         that the default logic of the special formats only applies if we don't
         get any explicit date (mday) specification.  In particular, overwrite
    -    the field with -1 in "now" and "yesterday", so that those formats will
    +    the field with -1 in "today" and "yesterday", so that those formats will
         be relative to the current date.  That makes specifications like "tea
         yesterday" behave more sensibly: instead of going backwards to the
         last tea-time and then a day back, Git will now understand that as the
    @@ date.c: void datestamp(struct strbuf *out)
      	if (tm->tm_mon < 0)
      		tm->tm_mon = now->tm_mon;
      	if (tm->tm_year < 0) {
    -@@ date.c: static void pending_number(struct tm *tm, int *num)
    - static void date_now(struct tm *tm, struct tm *now, int *num)
    - {
    - 	*num = 0;
    -+	tm->tm_mday = -1;
    - 	update_tm(tm, now, 0);
    - }
    - 
    +@@ date.c: static void date_now(struct tm *tm, struct tm *now, int *num)
      static void date_yesterday(struct tm *tm, struct tm *now, int *num)
      {
      	*num = 0;
    @@ date.c: static void pending_number(struct tm *tm, int *num)
      }
      
      static void date_pm(struct tm *tm, struct tm *now UNUSED, int *num)
    +@@ date.c: static void date_today(struct tm *tm, struct tm *now, int *num UNUSED)
    + 	if (tm->tm_hour == now->tm_hour &&
    + 	    tm->tm_min == now->tm_min &&
    + 	    tm->tm_sec == now->tm_sec)
    +-		date_time(tm, now, 0);
    ++		date_time(tm, 0);
    ++	tm->tm_mday = -1;
    + 	update_tm(tm, now, 0);
    + }
    + 
     
      ## t/t0006-date.sh ##
     @@ t/t0006-date.sh: check_approxidate '3:00' '2009-08-30 03:00:00'

base-commit: 94f057755b7941b321fd11fec1b2e3ca5313a4e0
-- 
2.30.2