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.
This fix will not affect the values returned by UNIX_TIMESTAMP() for leap seconds.
But note that when converting the value returned by UNIX_TIMESTAMP() to broken 
down time the correction of leap seconds will still be applied.
Note that this fix will make a difference *only* if the OS is specially configured
to return leap seconds from the OS time calls or when using a MySQL time zone 
defintion that has leap seconds.
Even after this change date/time literals (or other broken down time 
representations) with leap seconds (ending on :59:60 or 59:61) will still be 
considered illegal and discarded by the server with an error or 
a warning depending on the sql mode.
Added a test case to demonstrate the effect of the fix.

mysql-test/r/timezone3.result:
  Bug #39920: test case
mysql-test/std_data/Moscow_leap:
  Bug #39920: updated the Moscow time zone to Dr. Olson's tzdata 2008i 
  to accomodate for the 2008 leap second
mysql-test/t/timezone3.test:
  Bug #39920: test case
sql/tztime.cc:
  Bug #39920: adjust leap seconds (:60 or :61) to :59
sql/tztime.h:
  Bug #39920: adjust leap seconds (:60 or :61) to :59

1 files changed, 22 insertions, 0 deletions

diff --git a/sql/tztime.cc b/sql/tztime.cc
index 709e3b64752..d3d952e3c1e 100644
--- a/sql/tztime.cc
+++ b/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) */