Fix for bug #31154: field.h:1649: virtual int Field_bit::cmp(const uchar*, const uchar*): Assertion

Problem: GROUP_CONCAT(DISTINCT BIT_FIELD...) uses a tree to store keys;
which are constructed using a temporary table fields,
see Item_func_group_concat::setup().
As a) we don't store null bits in the tree where the bit fields store parts 
of their data and b) there's no method to properly compare two table records
we've got problem.

Fix: convert BIT fields to INT in the temporary table used.


mysql-test/r/func_gconcat.result:
  Fix for bug #31154: field.h:1649: virtual int Field_bit::cmp(const uchar*, const uchar*): Assertion
    - test result.
mysql-test/t/func_gconcat.test:
  Fix for bug #31154: field.h:1649: virtual int Field_bit::cmp(const uchar*, const uchar*): Assertion
    - test case.
sql/item_sum.cc:
  Fix for bug #31154: field.h:1649: virtual int Field_bit::cmp(const uchar*, const uchar*): Assertion
    - force the create_tmp_table() to convert BIT columns to INT 
      in order to be able to compare records containing BIT fields.

mysql-test/r/func_gconcat.result

@@ -819,4 +819,46 @@ id	group_concat(b.name)
 1	ra,ra
 2	ra,ra
 drop table t1;
+create table t1(a bit not null);
+insert into t1 values (), (), ();
+Warnings:
+Warning	1364	Field 'a' doesn't have a default value
+select group_concat(distinct a) from t1;
+group_concat(distinct a)
+0
+select group_concat(distinct a order by a) from t1;
+group_concat(distinct a order by a)
+0
+drop table t1;
+create table t1(a bit(2) not null);
+insert into t1 values (1), (0), (0), (3), (1);
+select group_concat(distinct a) from t1;
+group_concat(distinct a)
+1,0,3
+select group_concat(distinct a order by a) from t1;
+group_concat(distinct a order by a)
+0,1,3
+select group_concat(distinct a order by a desc) from t1;
+group_concat(distinct a order by a desc)
+3,1,0
+drop table t1;
+create table t1(a bit(2), b varchar(10), c bit);
+insert into t1 values (1, 'a', 0), (0, 'b', 1), (0, 'c', 0), (3, 'd', 1),
+(1, 'e', 1), (3, 'f', 1), (0, 'g', 1);
+select group_concat(distinct a, c) from t1;
+group_concat(distinct a, c)
+10,01,00,31,11
+select group_concat(distinct a, c order by a) from t1;
+group_concat(distinct a, c order by a)
+00,01,11,10,31
+select group_concat(distinct a, c) from t1;
+group_concat(distinct a, c)
+10,01,00,31,11
+select group_concat(distinct a, c order by a, c) from t1;
+group_concat(distinct a, c order by a, c)
+00,01,10,11,31
+select group_concat(distinct a, c order by a desc, c desc) from t1;
+group_concat(distinct a, c order by a desc, c desc)
+31,11,10,01,00
+drop table t1;
 End of 5.0 tests

mysql-test/t/func_gconcat.test

@@ -562,4 +562,32 @@ insert into t1 (id, name) values (2, "
 select b.id, group_concat(b.name) from t1 a, t1 b group by b.id;
 drop table t1;
 
+#
+# Bug #31154: group_concat() and bit fields;
+#
+create table t1(a bit not null);
+insert into t1 values (), (), ();
+select group_concat(distinct a) from t1;
+select group_concat(distinct a order by a) from t1;
+drop table t1;
+
+create table t1(a bit(2) not null);
+insert into t1 values (1), (0), (0), (3), (1);
+select group_concat(distinct a) from t1;
+select group_concat(distinct a order by a) from t1;
+select group_concat(distinct a order by a desc) from t1;
+drop table t1;
+
+create table t1(a bit(2), b varchar(10), c bit);
+insert into t1 values (1, 'a', 0), (0, 'b', 1), (0, 'c', 0), (3, 'd', 1),
+(1, 'e', 1), (3, 'f', 1), (0, 'g', 1);
+select group_concat(distinct a, c) from t1;
+select group_concat(distinct a, c order by a) from t1;
+select group_concat(distinct a, c) from t1;
+select group_concat(distinct a, c order by a, c) from t1;
+select group_concat(distinct a, c order by a desc, c desc) from t1;
+
+drop table t1;
+
+
 --echo End of 5.0 tests

sql/item_sum.cc

@@ -3307,15 +3307,34 @@ bool Item_func_group_concat::setup(THD *thd)
   count_field_types(select_lex, tmp_table_param, all_fields, 0);
   tmp_table_param->force_copy_fields= force_copy_fields;
   DBUG_ASSERT(table == 0);
+  if (arg_count_order > 0 || distinct)
+  {
     /*
       Currently we have to force conversion of BLOB values to VARCHAR's
       if we are to store them in TREE objects used for ORDER BY and
       DISTINCT. This leads to truncation if the BLOB's size exceeds
       Field_varstring::MAX_SIZE.
     */
-  if (arg_count_order > 0 || distinct)
     set_if_smaller(tmp_table_param->convert_blob_length, 
                    Field_varstring::MAX_SIZE);
+
+    /*
+      Force the create_tmp_table() to convert BIT columns to INT
+      as we cannot compare two table records containg BIT fields
+      stored in the the tree used for distinct/order by.
+      Moreover we don't even save in the tree record null bits 
+      where BIT fields store parts of their data.
+    */
+    List_iterator_fast<Item> li(all_fields);
+    Item *item;
+    while ((item= li++))
+    {
+      if (item->type() == Item::FIELD_ITEM && 
+          ((Item_field*) item)->field->type() == FIELD_TYPE_BIT)
+        item->marker= 4;
+    }
+  }
+
   /*
     We have to create a temporary table to get descriptions of fields
     (types, sizes and so on).