BUG#25250768: WRITING ON A READ_ONLY=ON SERVER WITHOUT SUPER PRIVILEGE

simplify.
add a test case.

mysql-test/r/read_only.result

@@ -30,6 +30,8 @@ create temporary table t3 (a int);
 create temporary table t4 (a int) select * from t3;
 insert into t3 values(1);
 insert into t4 select * from t3;
+create table t3 (a int);
+ERROR HY000: The MariaDB server is running with the --read-only option so it cannot execute this statement
 update t1,t3 set t1.a=t3.a+1 where t1.a=t3.a;
 ERROR HY000: The MariaDB server is running with the --read-only option so it cannot execute this statement
 update t1,t3 set t3.a=t1.a+1 where t1.a=t3.a;

mysql-test/t/read_only.test

@@ -80,6 +80,9 @@ insert into t3 values(1);
 
 insert into t4 select * from t3;
 
+--error ER_OPTION_PREVENTS_STATEMENT
+create table t3 (a int);
+
 # a non-temp table updated:
 --error ER_OPTION_PREVENTS_STATEMENT
 update t1,t3 set t1.a=t3.a+1 where t1.a=t3.a;

sql/sql_parse.cc

@@ -835,24 +835,16 @@ static my_bool deny_updates_if_read_only_option(THD *thd,
   if (lex->sql_command == SQLCOM_UPDATE_MULTI)
     DBUG_RETURN(FALSE);
 
-  const my_bool create_temp_tables= 
-    (lex->sql_command == SQLCOM_CREATE_TABLE) &&
-    (lex->create_info.options & HA_LEX_CREATE_TMP_TABLE);
-
-  const my_bool create_real_tables=
-    (lex->sql_command == SQLCOM_CREATE_TABLE) &&
-    !(lex->create_info.options & HA_LEX_CREATE_TMP_TABLE);
-
-  const my_bool drop_temp_tables= 
-    (lex->sql_command == SQLCOM_DROP_TABLE) &&
-    lex->drop_temporary;
-
-  const my_bool update_real_tables=
-    ((create_real_tables ||
-      some_non_temp_table_to_be_updated(thd, all_tables)) &&
-     !(create_temp_tables || drop_temp_tables));
+  /*
+    a table-to-be-created is not in the temp table list yet,
+    so CREATE TABLE needs a special treatment
+  */
+  const bool update_real_tables=
+    lex->sql_command == SQLCOM_CREATE_TABLE
+    ? !(lex->create_info.options & HA_LEX_CREATE_TMP_TABLE)
+    : some_non_temp_table_to_be_updated(thd, all_tables);
 
-  const my_bool create_or_drop_databases=
+  const bool create_or_drop_databases=
     (lex->sql_command == SQLCOM_CREATE_DB) ||
     (lex->sql_command == SQLCOM_DROP_DB);