MDEV-32235: mysql_json cannot be used on newly created table

- Closes PR #2839
- Usage of `Column_definition_fix_attributes()` suggested by Alexandar
  Barkov - thanks bar, that is better than hook in server code
  (reverted 22f3ebe4)
  - This method is called after parsing the data type:
    * in `CREATE/ALTER TABLE`
    * in SP: return data type, parameter data type, variable data type
  - We want to disallow all these use cases of MYSQL_JSON.

- Reviewer: bar@mariadb.com
            cvicentiu@mariadb.org

mysql-test/main/mysql_json_table_recreate.result

@@ -30,6 +30,12 @@ show create table mysql_json_test;
 ERROR HY000: Table rebuild required. Please do "ALTER TABLE `test.mysql_json_test` FORCE" or dump/reload to fix it!
 select * from mysql_json_test;
 ERROR HY000: Table rebuild required. Please do "ALTER TABLE `test.mysql_json_test` FORCE" or dump/reload to fix it!
+CREATE TABLE t2 AS SELECT * FROM mysql_json_test;
+ERROR HY000: Table rebuild required. Please do "ALTER TABLE `test.mysql_json_test` FORCE" or dump/reload to fix it!
+CREATE TABLE t2 (a mysql_json /*new column*/) AS SELECT * FROM mysql_json_test;
+ERROR HY000: 'MYSQL_JSON' is not allowed in this context
+CREATE TABLE t2 (actual mysql_json /*existing column*/) AS SELECT * FROM mysql_json_test;
+ERROR HY000: 'MYSQL_JSON' is not allowed in this context
 LOCK TABLES mysql_json_test WRITE;
 ERROR HY000: Table rebuild required. Please do "ALTER TABLE `test.mysql_json_test` FORCE" or dump/reload to fix it!
 alter table mysql_json_test force;
@@ -181,12 +187,7 @@ t1	CREATE TABLE `t1` (
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
 drop table t1;
 create table t1(j mysql_json);
-show create table t1;
-Table	Create Table
-t1	CREATE TABLE `t1` (
-  `j` mysql_json /* JSON from MySQL 5.7 */ CHARACTER SET utf8mb4 COLLATE utf8mb4_bin DEFAULT NULL
-) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
-drop table t1;
+ERROR HY000: 'MYSQL_JSON' is not allowed in this context
 create table `testjson` (
 `t` json /* JSON from MySQL 5.7*/ CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci;
@@ -211,5 +212,30 @@ testjson	CREATE TABLE `testjson` (
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
 drop table testjson;
 #
+# MDEV-32235: mysql_json cannot be used on newly created table
+#
+CREATE TABLE t(j mysql_json);
+ERROR HY000: 'MYSQL_JSON' is not allowed in this context
+CREATE TABLE IF NOT EXISTS t(j mysql_json);
+ERROR HY000: 'MYSQL_JSON' is not allowed in this context
+CREATE OR REPLACE TABLE t(j mysql_json);
+ERROR HY000: 'MYSQL_JSON' is not allowed in this context
+CREATE TEMPORARY TABLE t(j mysql_json);
+ERROR HY000: 'MYSQL_JSON' is not allowed in this context
+CREATE TABLE t1 (a TEXT);
+ALTER TABLE t1 MODIFY a mysql_json;
+ERROR HY000: 'MYSQL_JSON' is not allowed in this context
+DROP TABLE t1;
+CREATE FUNCTION f1() RETURNS mysql_json RETURN NULL;
+ERROR HY000: 'MYSQL_JSON' is not allowed in this context
+CREATE FUNCTION f1(a mysql_json) RETURNS INT RETURN 0;
+ERROR HY000: 'MYSQL_JSON' is not allowed in this context
+CREATE PROCEDURE p1()
+BEGIN
+DECLARE a mysql_json;
+END;
+$$
+ERROR HY000: 'MYSQL_JSON' is not allowed in this context
+#
 # End of 10.5 tests
 #

mysql-test/main/mysql_json_table_recreate.test

@@ -51,6 +51,13 @@ show create table mysql_json_test;
 --error ER_TABLE_NEEDS_REBUILD
 select * from mysql_json_test;
 
+--error ER_TABLE_NEEDS_REBUILD
+CREATE TABLE t2 AS SELECT * FROM mysql_json_test;
+--error ER_NOT_ALLOWED_IN_THIS_CONTEXT
+CREATE TABLE t2 (a mysql_json /*new column*/) AS SELECT * FROM mysql_json_test;
+--error ER_NOT_ALLOWED_IN_THIS_CONTEXT
+CREATE TABLE t2 (actual mysql_json /*existing column*/) AS SELECT * FROM mysql_json_test;
+
 --error ER_TABLE_NEEDS_REBUILD
 LOCK TABLES mysql_json_test WRITE;
 
@@ -97,9 +104,8 @@ drop table mysql_json_test_big;
 create table t1(j json);
 show create table t1;
 drop table t1;
+--error ER_NOT_ALLOWED_IN_THIS_CONTEXT
 create table t1(j mysql_json);
-show create table t1;
-drop table t1;
 # `json` type should not have character set and collation other than utf8mb4_bin
 --error ER_PARSE_ERROR
 create table `testjson` (
@@ -121,6 +127,37 @@ create table `testjson` (
 show create table testjson;
 drop table testjson;
 
+--echo #
+--echo # MDEV-32235: mysql_json cannot be used on newly created table
+--echo #
+
+--error ER_NOT_ALLOWED_IN_THIS_CONTEXT
+CREATE TABLE t(j mysql_json);
+--error ER_NOT_ALLOWED_IN_THIS_CONTEXT
+CREATE TABLE IF NOT EXISTS t(j mysql_json);
+--error ER_NOT_ALLOWED_IN_THIS_CONTEXT
+CREATE OR REPLACE TABLE t(j mysql_json);
+--error ER_NOT_ALLOWED_IN_THIS_CONTEXT
+CREATE TEMPORARY TABLE t(j mysql_json);
+
+CREATE TABLE t1 (a TEXT);
+--error ER_NOT_ALLOWED_IN_THIS_CONTEXT
+ALTER TABLE t1 MODIFY a mysql_json;
+DROP TABLE t1;
+
+--error ER_NOT_ALLOWED_IN_THIS_CONTEXT
+CREATE FUNCTION f1() RETURNS mysql_json RETURN NULL;
+--error ER_NOT_ALLOWED_IN_THIS_CONTEXT
+CREATE FUNCTION f1(a mysql_json) RETURNS INT RETURN 0;
+DELIMITER $$;
+--error ER_NOT_ALLOWED_IN_THIS_CONTEXT
+CREATE PROCEDURE p1()
+BEGIN
+  DECLARE a mysql_json;
+END;
+$$
+DELIMITER ;$$
+
 --echo #
 --echo # End of 10.5 tests
 --echo #

plugin/type_mysql_json/type.cc

@@ -37,6 +37,11 @@ class Type_handler_mysql_json: public Type_handler_blob
   Field *make_table_field(MEM_ROOT *, const LEX_CSTRING *,
                           const Record_addr &, const Type_all_attributes &,
                           TABLE_SHARE *) const override;
+  bool Column_definition_fix_attributes(Column_definition *c) const override
+  {
+    my_error(ER_NOT_ALLOWED_IN_THIS_CONTEXT, MYF(0), "MYSQL_JSON");
+    return true;
+  }
   void Column_definition_reuse_fix_attributes(THD *thd,
                                               Column_definition *def,
                                               const Field *field) const override;