Fixed LP BUG#615378 Incorrect processing of NULL result in Item_cache fixed.

mysql-test/r/subselect_cache.result

@@ -3272,3 +3272,41 @@ FROM t2 ) AND table1 .`col_varchar_key` OR table1 .`pk` ;
 col_varchar_nokey
 drop table t1,t2;
 set @@optimizer_switch= default;
+# LP BUG#615378 (incorrect NULL result returning in Item_cache)
+CREATE TABLE `t1` (
+`pk` int(11) NOT NULL AUTO_INCREMENT,
+`col_varchar_key` varchar(1) DEFAULT NULL,
+PRIMARY KEY (`pk`),
+KEY `col_varchar_key` (`col_varchar_key`)
+) DEFAULT CHARSET=latin1;
+INSERT INTO `t1` VALUES (10,'v');
+INSERT INTO `t1` VALUES (11,'r');
+CREATE TABLE `t2` (
+`pk` int(11) NOT NULL AUTO_INCREMENT,
+`col_varchar_key` varchar(1) DEFAULT NULL,
+PRIMARY KEY (`pk`),
+KEY `col_varchar_key` (`col_varchar_key`)
+) DEFAULT CHARSET=latin1;
+INSERT INTO `t2` VALUES (1,'r');
+INSERT INTO `t2` VALUES (2,'c');
+CREATE TABLE `t3` (
+`pk` int(11) NOT NULL AUTO_INCREMENT,
+`col_varchar_key` varchar(1) DEFAULT NULL,
+PRIMARY KEY (`pk`),
+KEY `col_varchar_key` (`col_varchar_key`)
+) DEFAULT CHARSET=latin1;
+INSERT INTO `t3` VALUES (1,'w');
+SELECT  SUM( DISTINCT table2 . `pk` ) AS field2 ,
+(SELECT SUM( SUBQUERY1_t2 . `pk` ) AS SUBQUERY1_field1
+FROM t2 AS SUBQUERY1_t2 STRAIGHT_JOIN
+t3 AS SUBQUERY1_t3 ON (SUBQUERY1_t3 . `pk` = SUBQUERY1_t2 . `pk` )
+WHERE  table1 . `col_varchar_key` ) AS field3  
+FROM ( t1 AS table1 LEFT JOIN
+( t2 AS table2 STRAIGHT_JOIN
+t3 AS table3 ON (table3 . `pk` = table2 . `pk` ) )
+ON (table3 . `col_varchar_key` = table1 . `col_varchar_key` ) )
+WHERE ( table1 . `pk` < 5 ) OR ( table1 . `col_varchar_key` IS NOT NULL)
+GROUP BY field3
+HAVING (field3 <= 'h' AND field2 != 4) ;
+field2	field3
+drop tables t1, t2, t3;

mysql-test/t/subselect_cache.test

@@ -1566,3 +1566,48 @@ FROM t2 ) AND table1 .`col_varchar_key` OR table1 .`pk` ;
 
 drop table t1,t2;
 set @@optimizer_switch= default;
+
+#
+--echo # LP BUG#615378 (incorrect NULL result returning in Item_cache)
+#
+# if bug present here will be valgrind warnings (due to attempt to process
+# uninialized decimal value) but the result will be correct (due to 
+# Item::null_value) 
+
+CREATE TABLE `t1` (
+  `pk` int(11) NOT NULL AUTO_INCREMENT,
+  `col_varchar_key` varchar(1) DEFAULT NULL,
+  PRIMARY KEY (`pk`),
+  KEY `col_varchar_key` (`col_varchar_key`)
+) DEFAULT CHARSET=latin1;
+INSERT INTO `t1` VALUES (10,'v');
+INSERT INTO `t1` VALUES (11,'r');
+CREATE TABLE `t2` (
+  `pk` int(11) NOT NULL AUTO_INCREMENT,
+  `col_varchar_key` varchar(1) DEFAULT NULL,
+  PRIMARY KEY (`pk`),
+  KEY `col_varchar_key` (`col_varchar_key`)
+) DEFAULT CHARSET=latin1;
+INSERT INTO `t2` VALUES (1,'r');
+INSERT INTO `t2` VALUES (2,'c');
+CREATE TABLE `t3` (
+  `pk` int(11) NOT NULL AUTO_INCREMENT,
+  `col_varchar_key` varchar(1) DEFAULT NULL,
+  PRIMARY KEY (`pk`),
+  KEY `col_varchar_key` (`col_varchar_key`)
+) DEFAULT CHARSET=latin1;
+INSERT INTO `t3` VALUES (1,'w');
+
+SELECT  SUM( DISTINCT table2 . `pk` ) AS field2 ,
+(SELECT SUM( SUBQUERY1_t2 . `pk` ) AS SUBQUERY1_field1
+ FROM t2 AS SUBQUERY1_t2 STRAIGHT_JOIN
+      t3 AS SUBQUERY1_t3 ON (SUBQUERY1_t3 . `pk` = SUBQUERY1_t2 . `pk` )
+ WHERE  table1 . `col_varchar_key` ) AS field3  
+FROM ( t1 AS table1 LEFT JOIN
+       ( t2 AS table2 STRAIGHT_JOIN
+         t3 AS table3 ON (table3 . `pk` = table2 . `pk` ) )
+       ON (table3 . `col_varchar_key` = table1 . `col_varchar_key` ) )
+WHERE ( table1 . `pk` < 5 ) OR ( table1 . `col_varchar_key` IS NOT NULL)
+GROUP BY field3
+HAVING (field3 <= 'h' AND field2 != 4) ;
+drop tables t1, t2, t3;

sql/item.cc

@@ -7750,8 +7750,11 @@ void Item_cache_int::store_longlong(Item *item, longlong val_arg)
 String *Item_cache_int::val_str(String *str)
 {
   DBUG_ASSERT(fixed == 1);
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return NULL;
+  }
   str->set(value, default_charset());
   return str;
 }
@@ -7760,8 +7763,11 @@ String *Item_cache_int::val_str(String *str)
 my_decimal *Item_cache_int::val_decimal(my_decimal *decimal_val)
 {
   DBUG_ASSERT(fixed == 1);
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return NULL;
+  }
   int2my_decimal(E_DEC_FATAL_ERROR, value, unsigned_flag, decimal_val);
   return decimal_val;
 }
@@ -7769,16 +7775,22 @@ my_decimal *Item_cache_int::val_decimal(my_decimal *decimal_val)
 double Item_cache_int::val_real()
 {
   DBUG_ASSERT(fixed == 1);
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return 0.0;
+  }
   return (double) value;
 }
 
 longlong Item_cache_int::val_int()
 {
   DBUG_ASSERT(fixed == 1);
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return 0;
+  }
   return value;
 }
 
@@ -7796,16 +7808,22 @@ bool Item_cache_real::cache_value()
 double Item_cache_real::val_real()
 {
   DBUG_ASSERT(fixed == 1);
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return 0.0;
+  }
   return value;
 }
 
 longlong Item_cache_real::val_int()
 {
   DBUG_ASSERT(fixed == 1);
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return 0;
+  }
   return (longlong) rint(value);
 }
 
@@ -7813,8 +7831,11 @@ longlong Item_cache_real::val_int()
 String* Item_cache_real::val_str(String *str)
 {
   DBUG_ASSERT(fixed == 1);
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return NULL;
+  }
   str->set_real(value, decimals, default_charset());
   return str;
 }
@@ -7823,8 +7844,11 @@ String* Item_cache_real::val_str(String *str)
 my_decimal *Item_cache_real::val_decimal(my_decimal *decimal_val)
 {
   DBUG_ASSERT(fixed == 1);
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return NULL;
+  }
   double2my_decimal(E_DEC_FATAL_ERROR, value, decimal_val);
   return decimal_val;
 }
@@ -7845,8 +7869,11 @@ double Item_cache_decimal::val_real()
 {
   DBUG_ASSERT(fixed);
   double res;
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return 0.0;
+  }
   my_decimal2double(E_DEC_FATAL_ERROR, &decimal_value, &res);
   return res;
 }
@@ -7855,8 +7882,11 @@ longlong Item_cache_decimal::val_int()
 {
   DBUG_ASSERT(fixed);
   longlong res;
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return 0;
+  }
   my_decimal2int(E_DEC_FATAL_ERROR, &decimal_value, unsigned_flag, &res);
   return res;
 }
@@ -7864,8 +7894,11 @@ longlong Item_cache_decimal::val_int()
 String* Item_cache_decimal::val_str(String *str)
 {
   DBUG_ASSERT(fixed);
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return NULL;
+  }
   my_decimal_round(E_DEC_FATAL_ERROR, &decimal_value, decimals, FALSE,
                    &decimal_value);
   my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value, 0, 0, 0, str);
@@ -7875,8 +7908,11 @@ String* Item_cache_decimal::val_str(String *str)
 my_decimal *Item_cache_decimal::val_decimal(my_decimal *val)
 {
   DBUG_ASSERT(fixed);
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return NULL;
+  }
   return &decimal_value;
 }
 
@@ -7911,12 +7947,13 @@ double Item_cache_str::val_real()
   DBUG_ASSERT(fixed == 1);
   int err_not_used;
   char *end_not_used;
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return 0.0;
-  if (value)
+  }
   return my_strntod(value->charset(), (char*) value->ptr(),
                     value->length(), &end_not_used, &err_not_used);
-  return (double) 0;
 }
 
 
@@ -7924,21 +7961,24 @@ longlong Item_cache_str::val_int()
 {
   DBUG_ASSERT(fixed == 1);
   int err;
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return 0;
-  if (value)
+  }
   return my_strntoll(value->charset(), value->ptr(),
                      value->length(), 10, (char**) 0, &err);
-  else
-    return (longlong)0;
 }
 
 
 String* Item_cache_str::val_str(String *str)
 {
   DBUG_ASSERT(fixed == 1);
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return 0;
+  }
   return value;
 }
 
@@ -7946,20 +7986,24 @@ String* Item_cache_str::val_str(String *str)
 my_decimal *Item_cache_str::val_decimal(my_decimal *decimal_val)
 {
   DBUG_ASSERT(fixed == 1);
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    null_value= TRUE;
     return NULL;
-  if (value)
+  }
   string2my_decimal(E_DEC_FATAL_ERROR, value, decimal_val);
-  else
-    decimal_val= 0;
   return decimal_val;
 }
 
 
 int Item_cache_str::save_in_field(Field *field, bool no_conversions)
 {
-  if (!value_cached && !cache_value())
+  if ((!value_cached && !cache_value()) || null_value)
+  {
+    field->set_notnull();
+    null_value= TRUE;
     return 0;
+  }
   int res= Item_cache::save_in_field(field, no_conversions);
   return (is_varbinary && field->type() == MYSQL_TYPE_STRING &&
           value->length() < field->field_length) ? 1 : res;