MDEV-12478 CONCAT function inside view casts values incorrectly with Oracle sql_mode

mysql-test/suite/compat/oracle/r/func_concat.result

@@ -3,12 +3,12 @@ EXPLAIN EXTENDED SELECT 'a'||'b'||'c';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
-Note	1003	select 'a' || 'b' || 'c' AS "'a'||'b'||'c'"
+Note	1003	select concat_operator_oracle(concat_operator_oracle('a','b'),'c') AS "'a'||'b'||'c'"
 EXPLAIN EXTENDED SELECT CONCAT('a'||'b'||'c');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
-Note	1003	select 'a' || 'b' || 'c' AS "CONCAT('a'||'b'||'c')"
+Note	1003	select concat_operator_oracle(concat_operator_oracle(concat_operator_oracle('a','b'),'c')) AS "CONCAT('a'||'b'||'c')"
 SELECT ''   || '';
 ''   || ''
 
@@ -204,3 +204,54 @@ NULL	NULL
 2	ab
 3	abc
 DROP TABLE t1;
+#
+# MDEV-12478 CONCAT function inside view casts values incorrectly with Oracle sql_mode
+#
+SET sql_mode=ORACLE;
+CREATE VIEW v1 AS SELECT 'foo'||NULL||'bar' AS test;
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE VIEW "v1" AS select concat_operator_oracle(concat_operator_oracle('foo',NULL),'bar') AS "test"	latin1	latin1_swedish_ci
+SELECT * FROM v1;
+test
+foobar
+SET sql_mode=DEFAULT;
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select concat_operator_oracle(concat_operator_oracle('foo',NULL),'bar') AS `test`	latin1	latin1_swedish_ci
+SELECT * FROM v1;
+test
+foobar
+DROP VIEW v1;
+SET sql_mode=DEFAULT;
+CREATE VIEW v1 AS SELECT CONCAT('foo',NULL,'bar') AS test;
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select concat('foo',NULL,'bar') AS `test`	latin1	latin1_swedish_ci
+SELECT * FROM v1;
+test
+NULL
+SET sql_mode=ORACLE;
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE VIEW "v1" AS select concat('foo',NULL,'bar') AS "test"	latin1	latin1_swedish_ci
+SELECT * FROM v1;
+test
+NULL
+DROP VIEW v1;
+SET sql_mode=DEFAULT;
+CREATE VIEW v1 AS SELECT '0'||'1' AS test;
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select '0' or '1' AS `test`	latin1	latin1_swedish_ci
+SELECT * FROM v1;
+test
+1
+SET sql_mode=ORACLE;
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE VIEW "v1" AS select '0' or '1' AS "test"	latin1	latin1_swedish_ci
+SELECT * FROM v1;
+test
+1
+DROP VIEW v1;

mysql-test/suite/compat/oracle/r/ps.result

@@ -178,9 +178,9 @@ EXECUTE IMMEDIATE 'SELECT :1 FROM DUAL' USING 10;
 # Testing erroneous and diallowed prepare source
 #
 EXECUTE IMMEDIATE _latin1'SELECT 1 AS c FROM ' || _latin2 'DUAL';
-ERROR HY000: Illegal mix of collations (latin1_swedish_ci,COERCIBLE) and (latin2_general_ci,COERCIBLE) for operation '||'
+ERROR HY000: Illegal mix of collations (latin1_swedish_ci,COERCIBLE) and (latin2_general_ci,COERCIBLE) for operation 'concat_operator_oracle'
 PREPARE stmt FROM _latin1'SELECT 1 AS c FROM ' || _latin2 'DUAL';
-ERROR HY000: Illegal mix of collations (latin1_swedish_ci,COERCIBLE) and (latin2_general_ci,COERCIBLE) for operation '||'
+ERROR HY000: Illegal mix of collations (latin1_swedish_ci,COERCIBLE) and (latin2_general_ci,COERCIBLE) for operation 'concat_operator_oracle'
 EXECUTE IMMEDIATE (SELECT 'SELECT 1');
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'SELECT 'SELECT 1')' at line 1
 PREPARE stmt FROM (SELECT 'SELECT 1');

mysql-test/suite/compat/oracle/r/sp-cursor-rowtype.result

@@ -758,7 +758,7 @@ END;
 END;
 $$
 CALL p1();
-ERROR HY000: Illegal mix of collations (latin1_bin,EXPLICIT) and (latin1_swedish_ci,EXPLICIT) for operation '||'
+ERROR HY000: Illegal mix of collations (latin1_bin,EXPLICIT) and (latin1_swedish_ci,EXPLICIT) for operation 'concat_operator_oracle'
 DROP PROCEDURE p1;
 #
 # Non-existing field

mysql-test/suite/compat/oracle/t/func_concat.test

@@ -83,3 +83,34 @@ SELECT LENGTH(a||b||c), a||b||c FROM t1 ORDER BY a,b,c;
 SELECT LENGTH(CONCAT(a||b||c)), CONCAT(a||b||c) FROM t1 ORDER BY a,b,c;
 
 DROP TABLE t1;
+
+--echo #
+--echo # MDEV-12478 CONCAT function inside view casts values incorrectly with Oracle sql_mode
+--echo #
+
+SET sql_mode=ORACLE;
+CREATE VIEW v1 AS SELECT 'foo'||NULL||'bar' AS test;
+SHOW CREATE VIEW v1;
+SELECT * FROM v1;
+SET sql_mode=DEFAULT;
+SHOW CREATE VIEW v1;
+SELECT * FROM v1;
+DROP VIEW v1;
+
+SET sql_mode=DEFAULT;
+CREATE VIEW v1 AS SELECT CONCAT('foo',NULL,'bar') AS test;
+SHOW CREATE VIEW v1;
+SELECT * FROM v1;
+SET sql_mode=ORACLE;
+SHOW CREATE VIEW v1;
+SELECT * FROM v1;
+DROP VIEW v1;
+
+SET sql_mode=DEFAULT;
+CREATE VIEW v1 AS SELECT '0'||'1' AS test;
+SHOW CREATE VIEW v1;
+SELECT * FROM v1;
+SET sql_mode=ORACLE;
+SHOW CREATE VIEW v1;
+SELECT * FROM v1;
+DROP VIEW v1;

sql/item_create.cc

@@ -644,6 +644,19 @@ class Create_func_concat : public Create_native_func
 };
 
 
+class Create_func_concat_operator_oracle : public Create_native_func
+{
+public:
+  virtual Item *create_native(THD *thd, LEX_STRING name, List<Item> *item_list);
+
+  static Create_func_concat_operator_oracle s_singleton;
+
+protected:
+  Create_func_concat_operator_oracle() {}
+  virtual ~Create_func_concat_operator_oracle() {}
+};
+
+
 class Create_func_decode_histogram : public Create_func_arg2
 {
 public:
@@ -3862,6 +3875,27 @@ Create_func_concat::create_native(THD *thd, LEX_STRING name,
     new (thd->mem_root) Item_func_concat(thd, *item_list);
 }
 
+Create_func_concat_operator_oracle
+  Create_func_concat_operator_oracle::s_singleton;
+
+Item*
+Create_func_concat_operator_oracle::create_native(THD *thd, LEX_STRING name,
+                                                  List<Item> *item_list)
+{
+  int arg_count= 0;
+
+  if (item_list != NULL)
+    arg_count= item_list->elements;
+
+  if (arg_count < 1)
+  {
+    my_error(ER_WRONG_PARAMCOUNT_TO_NATIVE_FCT, MYF(0), name.str);
+    return NULL;
+  }
+
+  return new (thd->mem_root) Item_func_concat_operator_oracle(thd, *item_list);
+}
+
 Create_func_decode_histogram Create_func_decode_histogram::s_singleton;
 
 Item *
@@ -6737,6 +6771,7 @@ static Native_func_registry func_array[] =
   { { C_STRING_WITH_LEN("COLUMN_JSON") }, BUILDER(Create_func_dyncol_json)},
   { { C_STRING_WITH_LEN("COMPRESS") }, BUILDER(Create_func_compress)},
   { { C_STRING_WITH_LEN("CONCAT") }, BUILDER(Create_func_concat)},
+  { { C_STRING_WITH_LEN("CONCAT_OPERATOR_ORACLE") }, BUILDER(Create_func_concat_operator_oracle)},
   { { C_STRING_WITH_LEN("CONCAT_WS") }, BUILDER(Create_func_concat_ws)},
   { { C_STRING_WITH_LEN("CONNECTION_ID") }, BUILDER(Create_func_connection_id)},
   { { C_STRING_WITH_LEN("CONV") }, BUILDER(Create_func_conv)},

sql/item_strfunc.h

@@ -303,12 +303,8 @@ class Item_func_concat_operator_oracle :public Item_func_concat
   Item_func_concat_operator_oracle(THD *thd, Item *a, Item *b)
    :Item_func_concat(thd, a, b)
   { }
-  void print(String *str, enum_query_type query_type)
-  {
-    print_op(str, query_type);
-  }
   String *val_str(String *);
-  const char *func_name() const { return "||"; }
+  const char *func_name() const { return "concat_operator_oracle"; }
   Item *get_copy(THD *thd, MEM_ROOT *mem_root)
   {
     return get_item_copy<Item_func_concat_operator_oracle>(thd, mem_root, this);

sql/sql_view.cc

@@ -1363,7 +1363,7 @@ bool mysql_make_view(THD *thd, TABLE_SHARE *share, TABLE_LIST *table,
       * MODE_NO_UNSIGNED_SUBTRACTION  affect execution
       - MODE_NO_DIR_IN_CREATE         affect table creation only
       - MODE_POSTGRESQL               compounded from other modes
-      - MODE_ORACLE                   compounded from other modes
+      - MODE_ORACLE                   affects Item creation (e.g for CONCAT)
       - MODE_MSSQL                    compounded from other modes
       - MODE_DB2                      compounded from other modes
       - MODE_MAXDB                    affect only CREATE TABLE parsing
@@ -1378,7 +1378,8 @@ bool mysql_make_view(THD *thd, TABLE_SHARE *share, TABLE_LIST *table,
       + MODE_NO_BACKSLASH_ESCAPES     affect expression parsing
     */
     thd->variables.sql_mode&= ~(MODE_PIPES_AS_CONCAT | MODE_ANSI_QUOTES |
-                                MODE_IGNORE_SPACE | MODE_NO_BACKSLASH_ESCAPES);
+                                MODE_IGNORE_SPACE | MODE_NO_BACKSLASH_ESCAPES |
+                                MODE_ORACLE);
 
     /* Parse the query. */