grant/revoke ... to/from current_role

mysql-test/suite/roles/grant_revoke_current.result

+grant select on *.* to current_role;
+ERROR 0L000: Invalid definer
+revoke select on *.* from current_role;
+ERROR 0L000: Invalid definer
+revoke all, grant option from current_role;
+ERROR 0L000: Invalid definer
+create role r1;
+grant insert on test.* to r1;
+grant r1 to current_user;
+set role r1;
+select current_role();
+current_role()
+r1
+grant select on *.* to current_role;
+show grants for current_role;
+Grants for r1
+GRANT SELECT ON *.* TO 'r1'
+GRANT INSERT ON `test`.* TO 'r1'
+revoke insert on test.* from current_role;
+show grants for current_role;
+Grants for r1
+GRANT SELECT ON *.* TO 'r1'
+revoke all, grant option from current_role;
+show grants for current_role;
+Grants for r1
+GRANT USAGE ON *.* TO 'r1'
+drop role r1;

mysql-test/suite/roles/grant_revoke_current.test

+--source include/not_embedded.inc
+
+--error ER_MALFORMED_DEFINER
+grant select on *.* to current_role;
+--error ER_MALFORMED_DEFINER
+revoke select on *.* from current_role;
+--error ER_MALFORMED_DEFINER
+revoke all, grant option from current_role;
+
+create role r1;
+grant insert on test.* to r1;
+grant r1 to current_user;
+set role r1;
+select current_role();
+
+grant select on *.* to current_role;
+show grants for current_role;
+revoke insert on test.* from current_role;
+show grants for current_role;
+revoke all, grant option from current_role;
+show grants for current_role;
+
+drop role r1;
+

sql/sql_yacc.yy

@@ -14356,9 +14356,11 @@ role_list:
 current_role:
           CURRENT_ROLE optional_braces
           {
-            if (!($$=(LEX_USER*) thd->alloc(sizeof(LEX_USER))))
+            if (!($$=(LEX_USER*) thd->calloc(sizeof(LEX_USER))))
               MYSQL_YYABORT;
             $$->user= current_role;
+            $$->plugin= empty_lex_str;
+            $$->auth= empty_lex_str;
           }
           ;