Bug#52177 crash with explain, row comparison, join, text field

The crash is the result of an attempt made by JOIN::optimize to evaluate
the WHERE condition when no records have been actually read.
The fix is to remove erroneous 'outer_join' variable check.


mysql-test/r/join.result:
  test result
mysql-test/t/join.test:
  test case
sql/sql_select.cc:
  removed erroneous 'outer_join' variable check.

mysql-test/r/join.result

@@ -930,4 +930,16 @@ Warnings:
 Note	1003	select 1 AS `1` from `test`.`t1` left join `test`.`t1` `t2` on((1 = 1)) left join (`test`.`t1` left join `test`.`t1` `t2` on((1 = 1))) on(rand()) where 1
 DROP VIEW v1;
 DROP TABLE t1;
+#
+# Bug#52177 crash with explain, row comparison, join, text field
+#
+CREATE TABLE t1 (a TINYINT, b TEXT, KEY (a));
+INSERT INTO t1 VALUES (0,''),(0,'');
+FLUSH TABLES;
+EXPLAIN SELECT 1 FROM t1 LEFT JOIN t1 a ON 1
+WHERE ROW(t1.a, 1111.11) = ROW(1111.11, 1111.11) AND
+ROW(t1.b, 1111.11) <=> ROW('','');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+DROP TABLE t1;
 End of 5.0 tests.

mysql-test/t/join.test

@@ -725,4 +725,15 @@ SELECT 1 FROM v1 right join v1 AS v2 ON RAND();
 DROP VIEW v1;
 DROP TABLE t1;
 
+--echo #
+--echo # Bug#52177 crash with explain, row comparison, join, text field
+--echo #
+CREATE TABLE t1 (a TINYINT, b TEXT, KEY (a));
+INSERT INTO t1 VALUES (0,''),(0,'');
+FLUSH TABLES;
+EXPLAIN SELECT 1 FROM t1 LEFT JOIN t1 a ON 1
+WHERE ROW(t1.a, 1111.11) = ROW(1111.11, 1111.11) AND
+ROW(t1.b, 1111.11) <=> ROW('','');
+DROP TABLE t1;
+
 --echo End of 5.0 tests.

sql/sql_select.cc

@@ -1029,7 +1029,7 @@ JOIN::optimize()
     }
   }
 
-  if (conds &&!outer_join && const_table_map != found_const_table_map && 
+  if (conds && const_table_map != found_const_table_map &&
       (select_options & SELECT_DESCRIBE) &&
       select_lex->master_unit() == &thd->lex->unit) // upper level SELECT
   {