MDEV-17928 Conversion from TIMESTAMP to VARCHAR SP variables does not work well on fractional digits

mysql-test/main/sp.result

@@ -8559,11 +8559,11 @@ RETURN a = timestamp'2038-01-19 03:14:07.999999'
 END
 $$
 SELECT f1(e) FROM t1;
-ERROR 22007: Truncated incorrect DOUBLE value: '2001-01-01 10:20:30'
+ERROR 22007: Truncated incorrect DOUBLE value: '2001-01-01 10:20:30.000000'
 SELECT f2(e) FROM t1;
-ERROR 22007: Truncated incorrect DOUBLE value: '2001-01-01 10:20:30'
+ERROR 22007: Truncated incorrect DOUBLE value: '2001-01-01 10:20:30.000000'
 SELECT f3(e) FROM t1;
-ERROR 22007: Truncated incorrect DOUBLE value: '2001-01-01 10:20:30'
+ERROR 22007: Truncated incorrect DOUBLE value: '2001-01-01 10:20:30.000000'
 DROP FUNCTION f1;
 DROP FUNCTION f2;
 DROP FUNCTION f3;

mysql-test/main/type_timestamp.result

@@ -1033,5 +1033,40 @@ CREATE TABLE t1 (a TIMESTAMP);
 INSERT INTO t1 SELECT CAST(20010101 AS UNSIGNED);
 DROP TABLE t1;
 #
+# MDEV-17928 Conversion from TIMESTAMP to VARCHAR SP variables does not work well on fractional digits
+#
+SET time_zone='+00:00';
+SET timestamp=UNIX_TIMESTAMP('2001-01-01 10:20:30.123456');
+CREATE PROCEDURE p1()
+BEGIN
+DECLARE ts10 TIMESTAMP(1) DEFAULT NOW();
+DECLARE ts16 TIMESTAMP(1) DEFAULT NOW(6);
+DECLARE dt10 DATETIME(1) DEFAULT NOW();
+DECLARE dt16 DATETIME(1) DEFAULT NOW(6);
+DECLARE vts10 VARCHAR(32) DEFAULT ts10;
+DECLARE vts16 VARCHAR(32) DEFAULT ts16;
+DECLARE vdt10 VARCHAR(32) DEFAULT dt10;
+DECLARE vdt16 VARCHAR(32) DEFAULT dt16;
+DECLARE tts10 TEXT(32) DEFAULT ts10;
+DECLARE tts16 TEXT(32) DEFAULT ts16;
+DECLARE tdt10 TEXT(32) DEFAULT dt10;
+DECLARE tdt16 TEXT(32) DEFAULT dt16;
+SELECT vts10, vts16, vdt10, vdt16;
+SELECT tts10, tts16, tdt10, tdt16;
+END;
+$$
+CALL p1;
+vts10	2001-01-01 10:20:30.0
+vts16	2001-01-01 10:20:30.1
+vdt10	2001-01-01 10:20:30.0
+vdt16	2001-01-01 10:20:30.1
+tts10	2001-01-01 10:20:30.0
+tts16	2001-01-01 10:20:30.1
+tdt10	2001-01-01 10:20:30.0
+tdt16	2001-01-01 10:20:30.1
+DROP PROCEDURE p1;
+SET timestamp=DEFAULT;
+SET time_zone=DEFAULT;
+#
 # End of 10.4 tests
 #

mysql-test/main/type_timestamp.test

@@ -625,6 +625,41 @@ CREATE TABLE t1 (a TIMESTAMP);
 INSERT INTO t1 SELECT CAST(20010101 AS UNSIGNED);
 DROP TABLE t1;
 
+
+--echo #
+--echo # MDEV-17928 Conversion from TIMESTAMP to VARCHAR SP variables does not work well on fractional digits
+--echo #
+
+SET time_zone='+00:00';
+SET timestamp=UNIX_TIMESTAMP('2001-01-01 10:20:30.123456');
+DELIMITER $$;
+CREATE PROCEDURE p1()
+BEGIN
+  DECLARE ts10 TIMESTAMP(1) DEFAULT NOW();
+  DECLARE ts16 TIMESTAMP(1) DEFAULT NOW(6);
+  DECLARE dt10 DATETIME(1) DEFAULT NOW();
+  DECLARE dt16 DATETIME(1) DEFAULT NOW(6);
+  DECLARE vts10 VARCHAR(32) DEFAULT ts10;
+  DECLARE vts16 VARCHAR(32) DEFAULT ts16;
+  DECLARE vdt10 VARCHAR(32) DEFAULT dt10;
+  DECLARE vdt16 VARCHAR(32) DEFAULT dt16;
+  DECLARE tts10 TEXT(32) DEFAULT ts10;
+  DECLARE tts16 TEXT(32) DEFAULT ts16;
+  DECLARE tdt10 TEXT(32) DEFAULT dt10;
+  DECLARE tdt16 TEXT(32) DEFAULT dt16;
+
+  SELECT vts10, vts16, vdt10, vdt16;
+  SELECT tts10, tts16, tdt10, tdt16;
+END;
+$$
+DELIMITER ;$$
+--vertical_results
+CALL p1;
+--horizontal_results
+DROP PROCEDURE p1;
+SET timestamp=DEFAULT;
+SET time_zone=DEFAULT;
+
 --echo #
 --echo # End of 10.4 tests
 --echo #

sql/field.cc

@@ -1831,12 +1831,9 @@ int Field::store(const char *to, size_t length, CHARSET_INFO *cs,
 }
 
 
-int Field::store_timestamp(my_time_t ts, ulong sec_part)
+int Field::store_timestamp_dec(const timeval &ts, uint dec)
 {
-  MYSQL_TIME ltime;
+  return store_time_dec(Datetime(get_thd(), ts).get_mysql_time(), dec);
-  THD *thd= get_thd();
-  thd->timestamp_to_TIME(&ltime, ts, sec_part, date_mode_t(0));
-  return store_time_dec(&ltime, decimals());
 }
 
 /**
@@ -5014,7 +5011,7 @@ int Field_timestamp::save_in_field(Field *to)
 {
   ulong sec_part;
   my_time_t ts= get_timestamp(&sec_part);
-  return to->store_timestamp(ts, sec_part);
+  return to->store_timestamp_dec(Timeval(ts, sec_part), decimals());
 }
 
 my_time_t Field_timestamp::get_timestamp(const uchar *pos,
@@ -5126,11 +5123,11 @@ int Field_timestamp::store(longlong nr, bool unsigned_val)
 }
 
 
-int Field_timestamp::store_timestamp(my_time_t ts, ulong sec_part)
+int Field_timestamp::store_timestamp_dec(const timeval &ts, uint dec)
 {
   int warn= 0;
   time_round_mode_t mode= Datetime::default_round_mode(get_thd());
-  store_TIMESTAMP(Timestamp(ts, sec_part).round(decimals(), mode, &warn));
+  store_TIMESTAMP(Timestamp(ts).round(decimals(), mode, &warn));
   if (warn)
   {
     /*
@@ -5144,7 +5141,7 @@ int Field_timestamp::store_timestamp(my_time_t ts, ulong sec_part)
     */
     set_warning(Sql_condition::WARN_LEVEL_WARN, ER_WARN_DATA_OUT_OF_RANGE, 1);
   }
-  if (ts == 0 && sec_part == 0 &&
+  if (ts.tv_sec == 0 && ts.tv_usec == 0 &&
       get_thd()->variables.sql_mode & (ulonglong) TIME_NO_ZERO_DATE)
   {
     ErrConvString s(

sql/field.h

@@ -784,7 +784,12 @@ public:
   virtual int  store(longlong nr, bool unsigned_val)=0;
   virtual int  store_decimal(const my_decimal *d)=0;
   virtual int  store_time_dec(const MYSQL_TIME *ltime, uint dec);
-  virtual int  store_timestamp(my_time_t timestamp, ulong sec_part);
+  virtual int  store_timestamp_dec(const timeval &ts, uint dec);
+  int store_timestamp(my_time_t timestamp, ulong sec_part)
+  {
+    return store_timestamp_dec(Timeval(timestamp, sec_part),
+                               TIME_SECOND_PART_DIGITS);
+  }
   int store_time(const MYSQL_TIME *ltime)
   { return store_time_dec(ltime, TIME_SECOND_PART_DIGITS); }
   int store(const char *to, size_t length, CHARSET_INFO *cs,
@@ -2744,7 +2749,7 @@ public:
   int  store(longlong nr, bool unsigned_val);
   int  store_time_dec(const MYSQL_TIME *ltime, uint dec);
   int  store_decimal(const my_decimal *);
-  int  store_timestamp(my_time_t timestamp, ulong sec_part);
+  int  store_timestamp_dec(const timeval &ts, uint dec);
   int  save_in_field(Field *to);
   double val_real(void);
   longlong val_int(void);

sql/sql_show.cc

@@ -7495,7 +7495,8 @@ static int get_schema_partitions_record(THD *thd, TABLE_LIST *tables,
         }
         else if (part_info->vers_info->interval.is_set())
         {
-          table->field[11]->store_timestamp((my_time_t)part_elem->range_value, 0);
+          Timeval tv((my_time_t) part_elem->range_value, 0);
+          table->field[11]->store_timestamp_dec(tv, AUTO_SEC_PART_DIGITS);
           table->field[11]->set_notnull();
         }
       }

sql/sql_type.h

@@ -2234,6 +2234,9 @@ public:
   Timestamp(my_time_t timestamp, ulong sec_part)
    :Timeval(timestamp, sec_part)
   { }
+  explicit Timestamp(const timeval &tv)
+   :Timeval(tv)
+  { }
   const struct timeval &tv() const { return *this; }
   long fraction_remainder(uint dec) const
   {

sql/structs.h

@@ -853,6 +853,9 @@ public:
     tv_sec= sec;
     tv_usec= usec;
   }
+  explicit Timeval(const timeval &tv)
+   :timeval(tv)
+  { }
 };