Backporting from 10.4 to 10.3: MDEV-17325 NULL-ability problems with LEAST() in combination with NO_ZERO_DATE and NO_ZERO_IN_DATE

This also fixes:
MDEV-17299 Assertion `maybe_null' failed in make_sortkey

Note, during merge of the 10.1 version of MDEV-17299,
please use the 10.3 version of the code (i.e. null merge the 10.1 version).

mysql-test/main/func_hybrid_type.result

@@ -3771,5 +3771,119 @@ t2	CREATE TABLE `t2` (
 DROP TABLE t1, t2;
 SET sql_mode=DEFAULT;
 #
+# MDEV-17325 NULL-ability problems with LEAST() in combination with NO_ZERO_DATE and NO_ZERO_IN_DATE
+#
+SET sql_mode='NO_ZERO_DATE,NO_ZERO_IN_DATE';
+SELECT
+LEAST('0000-00-00',DATE'2001-01-01') AS s1,
+LEAST('0001-00-01',DATE'2001-01-01') AS s2,
+LEAST('0000-00-00',TIMESTAMP'2001-01-01 00:00:00') AS s3,
+LEAST('0001-00-01',TIMESTAMP'2001-01-01 00:00:00') AS s4,
+LEAST(0,DATE'2001-01-01') AS i1,
+LEAST(20010001,DATE'2001-01-01') AS i2,
+LEAST(0,TIMESTAMP'2001-01-01 00:00:00') AS i3,
+LEAST(20010001,TIMESTAMP'2001-01-01 00:00:00') AS i4;
+Catalog	Database	Table	Table_alias	Column	Column_alias	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
+def					s1	10	10	0	Y	128	0	63
+def					s2	10	10	0	Y	128	0	63
+def					s3	12	26	0	Y	128	6	63
+def					s4	12	26	0	Y	128	6	63
+def					i1	10	10	0	Y	128	0	63
+def					i2	10	10	0	Y	128	0	63
+def					i3	12	19	0	Y	128	0	63
+def					i4	12	19	0	Y	128	0	63
+s1	s2	s3	s4	i1	i2	i3	i4
+NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
+Warnings:
+Warning	1292	Incorrect datetime value: '0000-00-00'
+Warning	1292	Incorrect datetime value: '0001-00-01'
+Warning	1292	Incorrect datetime value: '0000-00-00 00:00:00'
+Warning	1292	Incorrect datetime value: '0001-00-01 00:00:00'
+Warning	1292	Incorrect datetime value: '0000-00-00'
+Warning	1292	Incorrect datetime value: '2001-00-01'
+Warning	1292	Incorrect datetime value: '0000-00-00 00:00:00'
+Warning	1292	Incorrect datetime value: '2001-00-01 00:00:00'
+SET sql_mode='NO_ZERO_DATE,NO_ZERO_IN_DATE';
+CREATE TABLE t1 AS SELECT
+LEAST('0000-00-00',DATE'2001-01-01') AS s1,
+LEAST('0001-00-01',DATE'2001-01-01') AS s2,
+LEAST('0000-00-00',TIMESTAMP'2001-01-01 00:00:00') AS s3,
+LEAST('0001-00-01',TIMESTAMP'2001-01-01 00:00:00') AS s4,
+LEAST(0,DATE'2001-01-01') AS i1,
+LEAST(20010001,DATE'2001-01-01') AS i2,
+LEAST(0,TIMESTAMP'2001-01-01 00:00:00') AS i3,
+LEAST(20010001,TIMESTAMP'2001-01-01 00:00:00') AS i4;
+Warnings:
+Warning	1292	Incorrect datetime value: '0000-00-00'
+Warning	1292	Incorrect datetime value: '0001-00-01'
+Warning	1292	Incorrect datetime value: '0000-00-00 00:00:00'
+Warning	1292	Incorrect datetime value: '0001-00-01 00:00:00'
+Warning	1292	Incorrect datetime value: '0000-00-00'
+Warning	1292	Incorrect datetime value: '2001-00-01'
+Warning	1292	Incorrect datetime value: '0000-00-00 00:00:00'
+Warning	1292	Incorrect datetime value: '2001-00-01 00:00:00'
+SELECT * FROM t1;
+s1	s2	s3	s4	i1	i2	i3	i4
+NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `s1` date DEFAULT NULL,
+  `s2` date DEFAULT NULL,
+  `s3` datetime(6) DEFAULT NULL,
+  `s4` datetime(6) DEFAULT NULL,
+  `i1` date DEFAULT NULL,
+  `i2` date DEFAULT NULL,
+  `i3` datetime DEFAULT NULL,
+  `i4` datetime DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t1;
+SET timestamp=UNIX_TIMESTAMP('2001-01-01 10:20:30');
+CREATE TABLE t1 AS SELECT LEAST(CURRENT_DATE,CURRENT_TIME) AS c1;
+SELECT * FROM t1;
+c1
+2001-01-01 00:00:00
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `c1` datetime NOT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t1;
+SET old_mode=ZERO_DATE_TIME_CAST;
+CREATE TABLE t1 AS SELECT LEAST(CURRENT_DATE,CURRENT_TIME) AS c1;
+Warnings:
+Warning	1292	Incorrect datetime value: '0000-00-00 10:20:30'
+SELECT * FROM t1;
+c1
+NULL
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `c1` datetime DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t1;
+SET old_mode=DEFAULT;
+SET timestamp=DEFAULT;
+SET sql_mode=DEFAULT;
+SET sql_mode='';
+SELECT LEAST(999,TIME'10:20:30') AS c1;
+c1
+NULL
+Warnings:
+Warning	1292	Incorrect datetime value: '999'
+CREATE TABLE t1 AS SELECT LEAST(999,TIME'10:20:30') AS c1;
+Warnings:
+Warning	1292	Incorrect datetime value: '999'
+SELECT * FROM t1;
+c1
+NULL
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `c1` time DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t1;
+SET sql_mode=DEFAULT;
+#
 # End of 10.3 tests
 #

mysql-test/main/func_hybrid_type.test

@@ -628,6 +628,68 @@ SET sql_mode=DEFAULT;
 
 
 --echo #
---echo # End of 10.3 tests
+--echo # MDEV-17325 NULL-ability problems with LEAST() in combination with NO_ZERO_DATE and NO_ZERO_IN_DATE
 --echo #
 
+SET sql_mode='NO_ZERO_DATE,NO_ZERO_IN_DATE';
+
+--disable_ps_protocol
+--enable_metadata
+SELECT
+  LEAST('0000-00-00',DATE'2001-01-01') AS s1,
+  LEAST('0001-00-01',DATE'2001-01-01') AS s2,
+  LEAST('0000-00-00',TIMESTAMP'2001-01-01 00:00:00') AS s3,
+  LEAST('0001-00-01',TIMESTAMP'2001-01-01 00:00:00') AS s4,
+  LEAST(0,DATE'2001-01-01') AS i1,
+  LEAST(20010001,DATE'2001-01-01') AS i2,
+  LEAST(0,TIMESTAMP'2001-01-01 00:00:00') AS i3,
+  LEAST(20010001,TIMESTAMP'2001-01-01 00:00:00') AS i4;
+--disable_metadata
+--enable_ps_protocol
+
+SET sql_mode='NO_ZERO_DATE,NO_ZERO_IN_DATE';
+CREATE TABLE t1 AS SELECT
+  LEAST('0000-00-00',DATE'2001-01-01') AS s1,
+  LEAST('0001-00-01',DATE'2001-01-01') AS s2,
+  LEAST('0000-00-00',TIMESTAMP'2001-01-01 00:00:00') AS s3,
+  LEAST('0001-00-01',TIMESTAMP'2001-01-01 00:00:00') AS s4,
+  LEAST(0,DATE'2001-01-01') AS i1,
+  LEAST(20010001,DATE'2001-01-01') AS i2,
+  LEAST(0,TIMESTAMP'2001-01-01 00:00:00') AS i3,
+  LEAST(20010001,TIMESTAMP'2001-01-01 00:00:00') AS i4;
+SELECT * FROM t1;
+SHOW CREATE TABLE t1;
+DROP TABLE t1;
+
+SET timestamp=UNIX_TIMESTAMP('2001-01-01 10:20:30');
+
+# A TIME always converts to a non-NULL DATETIME with the new CAST style
+# Expect a NOT NULL column
+CREATE TABLE t1 AS SELECT LEAST(CURRENT_DATE,CURRENT_TIME) AS c1;
+SELECT * FROM t1;
+SHOW CREATE TABLE t1;
+DROP TABLE t1;
+
+# A TIME can convert to a NULL DATETIME with old CAST style
+# Expect a NULL-able column
+SET old_mode=ZERO_DATE_TIME_CAST;
+CREATE TABLE t1 AS SELECT LEAST(CURRENT_DATE,CURRENT_TIME) AS c1;
+SELECT * FROM t1;
+SHOW CREATE TABLE t1;
+DROP TABLE t1;
+SET old_mode=DEFAULT;
+SET timestamp=DEFAULT;
+
+SET sql_mode=DEFAULT;
+
+SET sql_mode='';
+SELECT LEAST(999,TIME'10:20:30') AS c1;
+CREATE TABLE t1 AS SELECT LEAST(999,TIME'10:20:30') AS c1;
+SELECT * FROM t1;
+SHOW CREATE TABLE t1;
+DROP TABLE t1;
+SET sql_mode=DEFAULT;
+
+--echo #
+--echo # End of 10.3 tests
+--echo #

mysql-test/main/type_date.result

@@ -863,6 +863,31 @@ d	COUNT(*)
 NULL	2
 DROP TABLE t1;
 #
+# MDEV-17299 Assertion `maybe_null' failed in make_sortkey
+#
+CREATE TABLE t1 (pk int NOT NULL, d1 date, d2 date NOT NULL);
+INSERT INTO t1 values (1,'2018-06-22','2018-06-22'),(2,'2018-07-11','2018-07-11');
+CREATE VIEW v1 AS SELECT * FROM t1;
+SELECT group_concat(d1/(CASE 'b' WHEN 'j' THEN 'c' END))
+FROM v1 GROUP BY greatest(pk, 0, d2);
+group_concat(d1/(CASE 'b' WHEN 'j' THEN 'c' END))
+NULL
+Warnings:
+Warning	1292	Incorrect datetime value: '1' for column `test`.`t1`.`pk` at row 1
+Warning	1292	Incorrect datetime value: '2' for column `test`.`t1`.`pk` at row 1
+Warning	1292	Incorrect datetime value: '1' for column `test`.`t1`.`pk` at row 1
+Warning	1292	Incorrect datetime value: '1' for column `test`.`t1`.`pk` at row 1
+Warning	1292	Incorrect datetime value: '2' for column `test`.`t1`.`pk` at row 2
+CREATE TABLE t2 AS SELECT greatest(pk, 0, d2) AS c1 FROM t1 LIMIT 0;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `c1` date DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+DROP TABLE t2;
+DROP VIEW v1;
+DROP TABLE t1;
+#
 # End of 10.1 tests
 #
 #

mysql-test/main/type_date.test

@@ -591,6 +591,20 @@ INSERT INTO t1 VALUES ('1985-05-13'),('1989-12-24');
 SELECT d, COUNT(*) FROM t1 GROUP BY d WITH ROLLUP HAVING CASE d WHEN '2017-05-25' THEN 0 ELSE 1 END;
 DROP TABLE t1;
 
+--echo #
+--echo # MDEV-17299 Assertion `maybe_null' failed in make_sortkey
+--echo #
+
+CREATE TABLE t1 (pk int NOT NULL, d1 date, d2 date NOT NULL);
+INSERT INTO t1 values (1,'2018-06-22','2018-06-22'),(2,'2018-07-11','2018-07-11');
+CREATE VIEW v1 AS SELECT * FROM t1;
+SELECT group_concat(d1/(CASE 'b' WHEN 'j' THEN 'c' END))
+  FROM v1 GROUP BY greatest(pk, 0, d2);
+CREATE TABLE t2 AS SELECT greatest(pk, 0, d2) AS c1 FROM t1 LIMIT 0;
+SHOW CREATE TABLE t2;
+DROP TABLE t2;
+DROP VIEW v1;
+DROP TABLE t1;
 
 --echo #
 --echo # End of 10.1 tests

sql/sql_type.cc

@@ -2933,6 +2933,97 @@ bool Type_handler::
 }
 
 
+bool Type_handler_temporal_result::
+       Item_func_min_max_fix_attributes(THD *thd, Item_func_min_max *func,
+                                        Item **items, uint nitems) const
+{
+  bool rc= Type_handler::Item_func_min_max_fix_attributes(thd, func,
+                                                          items, nitems);
+  if (rc || func->maybe_null)
+    return rc;
+  /*
+    LEAST/GREATES(non-temporal, temporal) can return NULL.
+    CAST functions Item_{time|datetime|date}_typecast always set maybe_full
+    to true. Here we try to detect nullability more thoroughly.
+    Perhaps CAST functions should also reuse this idea eventually.
+  */
+  const Type_handler *hf= func->type_handler();
+  for (uint i= 0; i < nitems; i++)
+  {
+    /*
+      If items[i] does not need conversion to the current temporal data
+      type, then we trust items[i]->maybe_null, which was already ORred
+      to func->maybe_null in the argument loop in fix_fields().
+      If items[i] requires conversion to the current temporal data type,
+      then conversion can fail and return NULL even for NOT NULL items.
+    */
+    const Type_handler *ha= items[i]->type_handler();
+    if (hf == ha)
+      continue; // No conversion.
+    if (ha->cmp_type() != TIME_RESULT)
+    {
+      func->maybe_null= true; // Conversion from non-temporal is not safe
+      break;
+    }
+    timestamp_type tf= hf->mysql_timestamp_type();
+    timestamp_type ta= ha->mysql_timestamp_type();
+    if (tf == ta ||
+        (tf == MYSQL_TIMESTAMP_DATETIME && ta == MYSQL_TIMESTAMP_DATE))
+    {
+      /*
+        If handlers have the same mysql_timestamp_type(),
+        then conversion is NULL safe. Conversion from DATE to DATETIME
+        is also safe. This branch includes data type pairs:
+        Function return type Argument type  Comment
+        -------------------- -------------  -------------
+        TIMESTAMP            TIMESTAMP      no conversion
+        TIMESTAMP            DATETIME       not possible
+        TIMESTAMP            DATE           not possible
+        DATETIME             DATETIME       no conversion
+        DATETIME             TIMESTAMP      safe conversion
+        DATETIME             DATE           safe conversion
+        DATE                 DATE           no conversion
+        TIME                 TIME           no conversion
+
+        Note, a function cannot return TIMESTAMP if it has non-TIMESTAMP
+        arguments (it would return DATETIME in such case).
+      */
+      DBUG_ASSERT(hf->field_type() != MYSQL_TYPE_TIMESTAMP || tf == ta);
+      continue;
+    }
+    /*
+      Here we have the following data type pairs that did not match
+      the condition above:
+
+      Function return type Argument type Comment
+      -------------------- ------------- -------
+      TIMESTAMP            TIME          Not possible
+      DATETIME             TIME          depends on OLD_MODE_ZERO_DATE_TIME_CAST
+      DATE                 TIMESTAMP     Not possible
+      DATE                 DATETIME      Not possible
+      DATE                 TIME          Not possible
+      TIME                 TIMESTAMP     Not possible
+      TIME                 DATETIME      Not possible
+      TIME                 DATE          Not possible
+
+      Most pairs are not possible, because the function data type
+      would be DATETIME (according to LEAST/GREATEST aggregation rules).
+      Conversion to DATETIME from TIME is not safe when
+      OLD_MODE_ZERO_DATE_TIME_CAST is set:
+      - negative TIME values cannot be converted to not-NULL DATETIME values
+      - TIME values can produce DATETIME values that do not pass
+        NO_ZERO_DATE and NO_ZERO_IN_DATE tests.
+    */
+    DBUG_ASSERT(hf->field_type() == MYSQL_TYPE_DATETIME);
+    if (!(thd->variables.old_behavior & OLD_MODE_ZERO_DATE_TIME_CAST))
+      continue;
+    func->maybe_null= true;
+    break;
+  }
+  return rc;
+}
+
+
 bool Type_handler_real_result::
        Item_func_min_max_fix_attributes(THD *thd, Item_func_min_max *func,
                                         Item **items, uint nitems) const

sql/sql_type.h

@@ -2138,6 +2138,8 @@ public:
                                    Item *source_expr, Item *source_const) const;
   bool subquery_type_allows_materialization(const Item *inner,
                                             const Item *outer) const;
+  bool Item_func_min_max_fix_attributes(THD *thd, Item_func_min_max *func,
+                                        Item **items, uint nitems) const;
   bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const;
   bool Item_sum_sum_fix_length_and_dec(Item_sum_sum *) const;
   bool Item_sum_avg_fix_length_and_dec(Item_sum_avg *) const;