MDEV-10397: Server crashes in key_copy with join_cache_level > 2 and join on BIT fields

For BIT field null_bit is not set to 0 even for a field defined as NOT NULL.
So now in the function TABLE::create_key_part_by_field, if the bit field is not nullable
then the null_bit is explicitly set to 0

mysql-test/r/join_outer.result

@@ -2339,5 +2339,18 @@ Warnings:
 Note	1003	select `test`.`t1`.`col1` AS `col1`,`test`.`t2`.`col1` AS `col1`,`test`.`t2`.`col3` AS `col3` from `test`.`t1` left join `test`.`t2` on((`test`.`t2`.`col2` = `test`.`t1`.`col1`)) where (`f1`(`test`.`t2`.`col3`,0) = 0)
 DROP FUNCTION f1;
 DROP TABLE t1,t2;
+#
+# MDEV-10397: Server crashes in key_copy with join_cache_level > 2 and join on BIT fields
+#
+CREATE TABLE t1 (b1 BIT NOT NULL);
+INSERT INTO t1 VALUES (0),(1);
+CREATE TABLE t2 (b2 BIT NOT NULL);
+INSERT INTO t2 VALUES (0),(1);
+SET SESSION JOIN_CACHE_LEVEL = 3;
+SELECT t1.b1+'0' , t2.b2 + '0' FROM t1 LEFT JOIN t2 ON b1 = b2;
+t1.b1+'0'	t2.b2 + '0'
+0	0
+1	1
+DROP TABLE t1, t2;
 # end of 5.5 tests
 SET optimizer_switch=@save_optimizer_switch;

mysql-test/r/join_outer_jcl6.result

@@ -2350,6 +2350,19 @@ Warnings:
 Note	1003	select `test`.`t1`.`col1` AS `col1`,`test`.`t2`.`col1` AS `col1`,`test`.`t2`.`col3` AS `col3` from `test`.`t1` left join `test`.`t2` on((`test`.`t2`.`col2` = `test`.`t1`.`col1`)) where (`f1`(`test`.`t2`.`col3`,0) = 0)
 DROP FUNCTION f1;
 DROP TABLE t1,t2;
+#
+# MDEV-10397: Server crashes in key_copy with join_cache_level > 2 and join on BIT fields
+#
+CREATE TABLE t1 (b1 BIT NOT NULL);
+INSERT INTO t1 VALUES (0),(1);
+CREATE TABLE t2 (b2 BIT NOT NULL);
+INSERT INTO t2 VALUES (0),(1);
+SET SESSION JOIN_CACHE_LEVEL = 3;
+SELECT t1.b1+'0' , t2.b2 + '0' FROM t1 LEFT JOIN t2 ON b1 = b2;
+t1.b1+'0'	t2.b2 + '0'
+0	0
+1	1
+DROP TABLE t1, t2;
 # end of 5.5 tests
 SET optimizer_switch=@save_optimizer_switch;
 set join_cache_level=default;

mysql-test/t/join_outer.test

@@ -1881,6 +1881,20 @@ DROP FUNCTION f1;
 
 DROP TABLE t1,t2;
 
+--echo #
+--echo # MDEV-10397: Server crashes in key_copy with join_cache_level > 2 and join on BIT fields
+--echo #
+
+CREATE TABLE t1 (b1 BIT NOT NULL);
+INSERT INTO t1 VALUES (0),(1);
+
+CREATE TABLE t2 (b2 BIT NOT NULL);
+INSERT INTO t2 VALUES (0),(1);
+
+SET SESSION JOIN_CACHE_LEVEL = 3;
+SELECT t1.b1+'0' , t2.b2 + '0' FROM t1 LEFT JOIN t2 ON b1 = b2;
+DROP TABLE t1, t2;
+
 --echo # end of 5.5 tests
 
 SET optimizer_switch=@save_optimizer_switch;

sql/table.cc

@@ -5987,6 +5987,14 @@ void TABLE::create_key_part_by_field(KEY_PART_INFO *key_part_info,
     might be reused.
   */
   key_part_info->store_length= key_part_info->length;
+  /*
+    For BIT fields null_bit is not set to 0 even if the field is defined
+    as NOT NULL, look at Field_bit::Field_bit
+  */
+  if (!field->real_maybe_null())
+  {
+    key_part_info->null_bit= 0;
+  }
 
   /*
      The total store length of the key part is the raw length of the field +