Backport of a 5.0.74 fix into 5.0.72sp1:

Bug #39920: MySQL cannot deal with Leap Second expression in string literal.

Updated MySQL time handling code to react correctly on UTC leap second additions.
MySQL functions that return the OS current time, like e.g. CURDATE(), NOW() etc
will return :59:59 instead of :59:60 or 59:61.
As a result the reader will receive :59:59 for 2 or 3 consecutive seconds
during the leap second.

Original changesets:
> revision-id: kgeorge@mysql.com-20081201141835-rg8nnnadujj5wl9f
> parent: gshchepa@mysql.com-20081114172557-xh0jlzwal8ze3cy6
> committer: Georgi Kodinov <kgeorge@mysql.com>
> branch nick: B39920-5.0-bugteam
> timestamp: Mon 2008-12-01 16:18:35 +0200

> revision-id: kgeorge@mysql.com-20081201154106-c310zzy5or043rqa
> parent: kgeorge@mysql.com-20081201145656-6kjq91oga5nxbbob
> committer: Georgi Kodinov <kgeorge@mysql.com>
> branch nick: B39920-merge-5.0-bugteam
> timestamp: Mon 2008-12-01 17:41:06 +0200

mysql-test/r/timezone2.result

@@ -110,7 +110,7 @@ i	ts
 362793610	1981-07-01 04:00:00
 select from_unixtime(362793609);
 from_unixtime(362793609)
-1981-07-01 03:59:60
+1981-07-01 03:59:59
 drop table t1;
 create table t1 (ts timestamp);
 set time_zone='UTC';

mysql-test/r/timezone3.result

@@ -17,6 +17,9 @@ insert into t1 values
 insert into t1 values
 (unix_timestamp('1981-07-01 03:59:59'),'1981-07-01 03:59:59'),
 (unix_timestamp('1981-07-01 04:00:00'),'1981-07-01 04:00:00');
+insert into t1 values
+(unix_timestamp('2009-01-01 02:59:59'),'2009-01-01 02:59:59'),
+(unix_timestamp('2009-01-01 03:00:00'),'2009-01-01 03:00:00');
 select i, from_unixtime(i), c from t1;
 i	from_unixtime(i)	c
 1072904422	2004-01-01 00:00:00	2004-01-01 00:00:00
@@ -31,6 +34,8 @@ i	from_unixtime(i)	c
 1099180821	2004-10-31 02:59:59	2004-10-31 02:59:59
 362793608	1981-07-01 03:59:59	1981-07-01 03:59:59
 362793610	1981-07-01 04:00:00	1981-07-01 04:00:00
+1230768022	2009-01-01 02:59:59	2009-01-01 02:59:59
+1230768024	2009-01-01 03:00:00	2009-01-01 03:00:00
 drop table t1;
 create table t1 (ts timestamp);
 insert into t1 values (19730101235900), (20040101235900);
@@ -39,3 +44,6 @@ ts
 1973-01-01 23:59:00
 2004-01-01 23:59:00
 drop table t1;
+SELECT FROM_UNIXTIME(1230768022), FROM_UNIXTIME(1230768023), FROM_UNIXTIME(1230768024);
+FROM_UNIXTIME(1230768022)	FROM_UNIXTIME(1230768023)	FROM_UNIXTIME(1230768024)
+2009-01-01 02:59:59	2009-01-01 02:59:59	2009-01-01 03:00:00

mysql-test/t/timezone3.test

@@ -45,6 +45,10 @@ insert into t1 values
   (unix_timestamp('1981-07-01 03:59:59'),'1981-07-01 03:59:59'),
   (unix_timestamp('1981-07-01 04:00:00'),'1981-07-01 04:00:00');
 
+insert into t1 values
+  (unix_timestamp('2009-01-01 02:59:59'),'2009-01-01 02:59:59'),
+  (unix_timestamp('2009-01-01 03:00:00'),'2009-01-01 03:00:00');
+
 select i, from_unixtime(i), c from t1;
 drop table t1;
 
@@ -58,4 +62,12 @@ insert into t1 values (19730101235900), (20040101235900);
 select * from t1;
 drop table t1;
 
+#
+# Test Bug #39920: MySQL cannot deal with Leap Second expression in string
+# literal
+#
+
+# 2009-01-01 02:59:59, 2009-01-01 02:59:60 and 2009-01-01 03:00:00
+SELECT FROM_UNIXTIME(1230768022), FROM_UNIXTIME(1230768023), FROM_UNIXTIME(1230768024);
+
 # End of 4.1 tests

sql/tztime.cc

@@ -1073,6 +1073,7 @@ Time_zone_system::gmt_sec_to_TIME(MYSQL_TIME *tmp, my_time_t t) const
   localtime_r(&tmp_t, &tmp_tm);
   localtime_to_TIME(tmp, &tmp_tm);
   tmp->time_type= MYSQL_TIMESTAMP_DATETIME;
+  adjust_leap_second(tmp);
 }
 
 
@@ -1157,6 +1158,7 @@ Time_zone_utc::gmt_sec_to_TIME(MYSQL_TIME *tmp, my_time_t t) const
   gmtime_r(&tmp_t, &tmp_tm);
   localtime_to_TIME(tmp, &tmp_tm);
   tmp->time_type= MYSQL_TIMESTAMP_DATETIME;
+  adjust_leap_second(tmp);
 }
 
 
@@ -1260,6 +1262,7 @@ void
 Time_zone_db::gmt_sec_to_TIME(MYSQL_TIME *tmp, my_time_t t) const
 {
   ::gmt_sec_to_TIME(tmp, t, tz_info);
+  adjust_leap_second(tmp);
 }
 
 
@@ -2373,6 +2376,25 @@ Time_zone *my_tz_find_with_opening_tz_tables(THD *thd, const String *name)
   DBUG_RETURN(tz);
 }
 
+
+/**
+  Convert leap seconds into non-leap
+
+  This function will convert the leap seconds added by the OS to 
+  non-leap seconds, e.g. 23:59:59, 23:59:60 -> 23:59:59, 00:00:01 ...
+  This check is not checking for years on purpose : although it's not a
+  complete check this way it doesn't require looking (and having installed)
+  the leap seconds table.
+
+  @param[in,out] broken down time structure as filled in by the OS
+*/
+
+void Time_zone::adjust_leap_second(MYSQL_TIME *t)
+{
+  if (t->second == 60 || t->second == 61)
+    t->second= 59;
+}
+
 #endif /* !defined(TESTTIME) && !defined(TZINFO2SQL) */
 
 

sql/tztime.h

@@ -55,6 +55,9 @@ public:
     allocated on MEM_ROOT and should not require destruction.
   */
   virtual ~Time_zone() {};
+
+protected:
+  static inline void adjust_leap_second(MYSQL_TIME *t);
 };
 
 extern Time_zone * my_tz_UTC;