Fixed bug mdev-5132.

Objects of the classes Item_func_isnull and Item_func_isnotnull
must have the flag sargable set to TRUE.
Set the value of the flag sargable only in constructors of the 
classes inherited from Item_int_func.

mysql-test/r/null.result

@@ -373,3 +373,12 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 SELECT * FROM t1 WHERE NOT (concat( dt, '1' ) IS NOT NULL);
 dt
 DROP TABLE t1;
+#
+# Bug mdev-5132: crash when exeicuting a join query
+#                with IS NULL and IS NOT NULL in where
+#
+CREATE TABLE t1 (a DATE, b INT, c INT, KEY(a), KEY(b), KEY(c)) ENGINE=MyISAM;
+CREATE TABLE t2 (d DATE) ENGINE=MyISAM;
+SELECT  * FROM t1,t2 WHERE  1 IS NOT NULL AND t1.b IS NULL;
+a	b	c	d
+DROP TABLE t1,t2;

mysql-test/t/null.test

@@ -283,3 +283,15 @@ SELECT * FROM t1 WHERE NOT (concat( dt, '1' ) IS NOT NULL);
 SELECT * FROM t1 WHERE NOT (concat( dt, '1' ) IS NOT NULL); 
 
 DROP TABLE t1;
+
+--echo #
+--echo # Bug mdev-5132: crash when exeicuting a join query
+--echo #                with IS NULL and IS NOT NULL in where
+--echo #
+
+CREATE TABLE t1 (a DATE, b INT, c INT, KEY(a), KEY(b), KEY(c)) ENGINE=MyISAM; 
+CREATE TABLE t2 (d DATE) ENGINE=MyISAM; 
+
+SELECT  * FROM t1,t2 WHERE  1 IS NOT NULL AND t1.b IS NULL;
+
+DROP TABLE t1,t2;

sql/item_cmpfunc.cc

@@ -539,8 +539,6 @@ void Item_bool_func2::fix_length_and_dec()
     to the collation of A.
   */
 
-  sargable= true;
-
   DTCollation coll;
   if (args[0]->result_type() == STRING_RESULT &&
       args[1]->result_type() == STRING_RESULT &&
@@ -2185,7 +2183,6 @@ void Item_func_between::fix_length_and_dec()
   THD *thd= current_thd;
   max_length= 1;
   compare_as_dates= 0;
-  sargable= true;
 
   /*
     As some compare functions are generated after sql_yacc,
@@ -3865,7 +3862,6 @@ void Item_func_in::fix_length_and_dec()
   uint found_types= 0;
   uint type_cnt= 0, i;
   Item_result cmp_type= STRING_RESULT;
-  sargable= true;
   left_result_type= args[0]->cmp_type();
   if (!(found_types= collect_cmp_types(args, arg_count, true)))
     return;
@@ -5492,6 +5488,7 @@ Item_equal::Item_equal(Item *f1, Item *f2, bool with_const_item)
   equal_items.push_back(f2);
   compare_as_dates= with_const_item && f2->cmp_type() == TIME_RESULT;
   upper_levels= NULL;
+  sargable= TRUE; 
 }
 
 
@@ -5521,6 +5518,7 @@ Item_equal::Item_equal(Item_equal *item_equal)
   compare_as_dates= item_equal->compare_as_dates;
   cond_false= item_equal->cond_false;
   upper_levels= item_equal->upper_levels;
+  sargable= TRUE;
 }
 
 
@@ -5944,7 +5942,6 @@ void Item_equal::fix_length_and_dec()
   Item *item= get_first(NO_PARTICULAR_TAB, NULL);
   eval_item= cmp_item::get_comparator(item->cmp_type(), item,
                                       item->collation.collation);
-  sargable= true;
 }
 
 

sql/item_cmpfunc.h

@@ -118,7 +118,7 @@ public:
   Item_bool_func(Item *a,Item *b) :Item_int_func(a,b) {}
   Item_bool_func(THD *thd, Item_bool_func *item) :Item_int_func(thd, item) {}
   bool is_bool_func() { return 1; }
-  void fix_length_and_dec() { decimals=0; max_length=1; sargable= true;}
+  void fix_length_and_dec() { decimals=0; max_length=1; }
   uint decimal_precision() const { return 1; }
 };
 
@@ -364,7 +364,8 @@ protected:
 
 public:
   Item_bool_func2(Item *a,Item *b)
-    :Item_int_func(a,b), cmp(tmp_arg, tmp_arg+1), abort_on_null(FALSE) {}
+    :Item_int_func(a,b), cmp(tmp_arg, tmp_arg+1),
+     abort_on_null(FALSE) { sargable= TRUE; }
   void fix_length_and_dec();
   void set_cmp_func()
   {
@@ -668,7 +669,7 @@ public:
   /* TRUE <=> arguments will be compared as dates. */
   Item *compare_as_dates;
   Item_func_between(Item *a, Item *b, Item *c)
-    :Item_func_opt_neg(a, b, c), compare_as_dates(FALSE) {}
+    :Item_func_opt_neg(a, b, c), compare_as_dates(FALSE) { sargable= TRUE; }
   longlong val_int();
   optimize_type select_optimize() const { return OPTIMIZE_KEY; }
   enum Functype functype() const   { return BETWEEN; }
@@ -1284,6 +1285,7 @@ public:
   {
     bzero(&cmp_items, sizeof(cmp_items));
     allowed_arg_cols= 0;  // Fetch this value from first argument
+    sargable= TRUE;
   }
   longlong val_int();
   bool fix_fields(THD *, Item **);
@@ -1349,7 +1351,7 @@ public:
 class Item_func_isnull :public Item_bool_func
 {
 public:
-  Item_func_isnull(Item *a) :Item_bool_func(a) {}
+  Item_func_isnull(Item *a) :Item_bool_func(a) { sargable= TRUE; }
   longlong val_int();
   enum Functype functype() const { return ISNULL_FUNC; }
   void fix_length_and_dec()
@@ -1410,7 +1412,8 @@ class Item_func_isnotnull :public Item_bool_func
 {
   bool abort_on_null;
 public:
-  Item_func_isnotnull(Item *a) :Item_bool_func(a), abort_on_null(0) {}
+  Item_func_isnotnull(Item *a) :Item_bool_func(a), abort_on_null(0)
+  { sargable= TRUE; }
   longlong val_int();
   enum Functype functype() const { return ISNOTNULL_FUNC; }
   void fix_length_and_dec()
@@ -1717,7 +1720,7 @@ public:
   inline Item_equal()
     : Item_bool_func(), with_const(FALSE), eval_item(0), cond_false(0),
       context_field(NULL)
-  { const_item_cache=0 ;}
+  { const_item_cache=0; sargable= TRUE; }
   Item_equal(Item *f1, Item *f2, bool with_const_item);
   Item_equal(Item_equal *item_equal);
   /* Currently the const item is always the first in the list of equal items */