MDEV-4335: Unexpected results when selecting on information_schema

- When converting a subquery to a semi-join, propagate OPTION_SCHEMA_TABLE.

mysql-test/r/subselect_sj.result

@@ -2772,4 +2772,14 @@ execute stmt;
 a	b
 deallocate prepare stmt;
 drop table t1,t2;
+#
+# MDEV-4335: Unexpected results when selecting on information_schema
+#
+CREATE TABLE t1 (db VARCHAR(64) DEFAULT NULL);
+INSERT INTO t1 VALUES ('mysql'),('information_schema');
+SELECT * FROM t1 WHERE db IN (SELECT `SCHEMA_NAME` FROM information_schema.SCHEMATA);
+db
+mysql
+information_schema
+DROP TABLE t1;
 set optimizer_switch=@subselect_sj_tmp;

mysql-test/r/subselect_sj_jcl6.result

@@ -2786,6 +2786,16 @@ execute stmt;
 a	b
 deallocate prepare stmt;
 drop table t1,t2;
+#
+# MDEV-4335: Unexpected results when selecting on information_schema
+#
+CREATE TABLE t1 (db VARCHAR(64) DEFAULT NULL);
+INSERT INTO t1 VALUES ('mysql'),('information_schema');
+SELECT * FROM t1 WHERE db IN (SELECT `SCHEMA_NAME` FROM information_schema.SCHEMATA);
+db
+information_schema
+mysql
+DROP TABLE t1;
 set optimizer_switch=@subselect_sj_tmp;
 #
 # BUG#49129: Wrong result with IN-subquery with join_cache_level=6 and firstmatch=off

mysql-test/t/subselect_sj.test

@@ -2481,6 +2481,13 @@ execute stmt;
 deallocate prepare stmt;
 drop table t1,t2;
 
+--echo #
+--echo # MDEV-4335: Unexpected results when selecting on information_schema
+--echo #
+CREATE TABLE t1 (db VARCHAR(64) DEFAULT NULL); 
+INSERT INTO t1 VALUES ('mysql'),('information_schema'); 
+SELECT * FROM t1 WHERE db IN (SELECT `SCHEMA_NAME` FROM information_schema.SCHEMATA); 
+DROP TABLE t1;
 
 # The following command must be the last one the file 
 set optimizer_switch=@subselect_sj_tmp;

sql/opt_subselect.cc

@@ -1493,6 +1493,9 @@ static bool convert_subq_to_sj(JOIN *parent_join, Item_in_subselect *subq_pred)
   */
   parent_lex->leaf_tables.concat(&subq_lex->leaf_tables);
 
+  if (subq_lex->options & OPTION_SCHEMA_TABLE)
+    parent_lex->options |= OPTION_SCHEMA_TABLE;
+
   /*
     Same as above for next_local chain
     (a theory: a next_local chain always starts with ::leaf_tables
@@ -1709,6 +1712,9 @@ static bool convert_subq_to_jtbm(JOIN *parent_join,
   */
   parent_lex->leaf_tables.push_back(jtbm);
 
+  if (subq_pred->unit->first_select()->options & OPTION_SCHEMA_TABLE)
+    parent_lex->options |= OPTION_SCHEMA_TABLE;
+
   /*
     Same as above for TABLE_LIST::next_local chain
     (a theory: a next_local chain always starts with ::leaf_tables