Re: [BUG] minor: wrong handling of GIT_AUTHOR_DATE

Junio C Hamano [off-list ref] writes:

You've taught people here and on the kernel list that the "date" can use
any non-digit-non-word as a word separator, and "git log --since 2.days"
is something you often do.

People who followed that advice would have gotten used to this already, e.g.

   $ git reflog delete master@{07.04.2005.15:15:00.-0700}

should not be broken.

I think your first hunk needs to distinguish between "very-long-precision
posint" (in which case we ignore because it is likely to be nanoseconds
fraction) and others.

Perhaps like this.

-- >8 --
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sat, 16 Aug 2008 16:17:50 -0700
Subject: [PATCH] date parsing: do not mistake fractional nanosecond that follow HH:MM:SS

Some program output nanosecond fractional after the usual HH:MM:SS format.
If the fraction is large enough, it can be interpreted as the seconds
since epoch, and can overwrite the already parsed date/time.

We also make sure we use the seconds since epoch interpretation only when
we have not seen any other date/time data in the input yet.

Note that we cannot unconditionally drop anything that follows '.'; people
have been taught that we allow '.' as a word separator and have got used
to formats like "--since 2.days" and "2008.08.16.01:23:45.-0700" to work.

Noticed-by: Hermann Gausterer
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <redacted>
---
 date.c |   16 +++++++++++++++-
 1 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/date.c b/date.c
index 35a5257..b2c5a8b 100644
--- a/date.c
+++ b/date.c

@@ -363,6 +363,11 @@ static int match_multi_number(unsigned long num, char c, const char *date, char
 			tm->tm_hour = num;
 			tm->tm_min = num2;
 			tm->tm_sec = num3;
+			if (*end == '.') {
+				num = strspn(end+1, "0123456789");
+				if (9 <= num)
+					end += num + 1;
+			}
 			break;
 		}
 		return 0;

@@ -402,6 +407,15 @@ static int match_multi_number(unsigned long num, char c, const char *date, char
 	return end - date;
 }
 
+/* Have we filled in any part of the time/date yet? */
+static inline int nodate(struct tm *tm)
+{
+	return tm->tm_year < 0 &&
+		tm->tm_mon < 0 &&
+		tm->tm_mday < 0 &&
+		!(tm->tm_hour | tm->tm_min | tm->tm_sec);
+}
+
 /*
  * We've seen a digit. Time? Year? Date?
  */

@@ -418,7 +432,7 @@ static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt
 	 * more than 8 digits. This is because we don't want to rule out
 	 * numbers like 20070606 as a YYYYMMDD date.
 	 */
-	if (num >= 100000000) {
+	if (num >= 100000000 && nodate(tm)) {
 		time_t time = num;
 		if (gmtime_r(&time, tm)) {
 			*tm_gmt = 1;

-- 
1.6.0.rc3.17.gc14c8