Bug#30998 Drop View breaks replication if view does not exist

When executing drop view statement on the master, the statement is not written into bin-log if any error occurs, this could cause master slave inconsistence if any view has been dropped. 

If some error occured and no view has been dropped, don't bin-log the statement, if at least one view has been dropped the query is bin-logged possible with an error.

mysql-test/suite/rpl/r/rpl_drop_view.result

+stop slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+reset master;
+reset slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+start slave;
+drop table if exists t1, t2;
+drop view if exists v1, v2, v3, not_exist_view;
+create table t1 (a int);
+create table t2 (b int);
+create table t3 (c int);
+create view v1 as select * from t1;
+create view v2 as select * from t2;
+create view v3 as select * from t3;
+drop view not_exist_view;
+ERROR 42S02: Unknown table 'not_exist_view'
+drop view v1, not_exist_view;
+ERROR 42S02: Unknown table 'not_exist_view'
+select * from v1;
+ERROR 42S02: Table 'test.v1' doesn't exist
+drop view v2, v3;
+select * from v1;
+ERROR 42S02: Table 'test.v1' doesn't exist
+select * from v2;
+ERROR 42S02: Table 'test.v2' doesn't exist
+select * from v3;
+ERROR 42S02: Table 'test.v3' doesn't exist

mysql-test/suite/rpl/t/rpl_drop_view.test

+# test case for bug#30998
+# Drop View breaks replication if view does not exist
+#
+
+source include/master-slave.inc;
+--disable_warnings
+drop table if exists t1, t2;
+drop view if exists v1, v2, v3, not_exist_view;
+--enable_warnings
+create table t1 (a int);
+create table t2 (b int);
+create table t3 (c int);
+create view v1 as select * from t1;
+create view v2 as select * from t2;
+create view v3 as select * from t3;
+--error 1051
+drop view not_exist_view;
+--error 1051
+drop view v1, not_exist_view;
+--error 1146
+select * from v1;
+drop view v2, v3;
+save_master_pos;
+connection slave;
+sync_with_master;
+--error 1146
+select * from v1;
+--error 1146
+select * from v2;
+--error 1146
+select * from v3;

sql/sql_view.cc

@@ -1465,6 +1465,8 @@ bool mysql_drop_view(THD *thd, TABLE_LIST *views, enum_drop_mode drop_mode)
   char *wrong_object_db= NULL, *wrong_object_name= NULL;
   bool error= FALSE;
   enum legacy_db_type not_used;
+  bool some_views_deleted= FALSE;
+  bool something_wrong= FALSE;
   DBUG_ENTER("mysql_drop_view");
 
   VOID(pthread_mutex_lock(&LOCK_open));
@@ -1506,6 +1508,8 @@ bool mysql_drop_view(THD *thd, TABLE_LIST *views, enum_drop_mode drop_mode)
     if (my_delete(path, MYF(MY_WME)))
       error= TRUE;
 
+    some_views_deleted= TRUE;
+
     /*
       For a view, there is only one table_share object which should never
       be used outside of LOCK_open
@@ -1523,29 +1527,32 @@ bool mysql_drop_view(THD *thd, TABLE_LIST *views, enum_drop_mode drop_mode)
     sp_cache_invalidate();
   }
 
-  if (error)
-  {
-    VOID(pthread_mutex_unlock(&LOCK_open));
-    DBUG_RETURN(TRUE);
-  }
   if (wrong_object_name)
   {
-    VOID(pthread_mutex_unlock(&LOCK_open));
     my_error(ER_WRONG_OBJECT, MYF(0), wrong_object_db, wrong_object_name, 
              "VIEW");
-    DBUG_RETURN(TRUE);
   }
   if (non_existant_views.length())
   {
-    VOID(pthread_mutex_unlock(&LOCK_open));
     my_error(ER_BAD_TABLE_ERROR, MYF(0), non_existant_views.c_ptr());
-    DBUG_RETURN(TRUE);
   }
 
-  write_bin_log(thd, TRUE, thd->query, thd->query_length);
+  something_wrong= error || wrong_object_name || non_existant_views.length();
+  if (some_views_deleted || !something_wrong)
+  {
+    /* if something goes wrong, bin-log with possible error code,
+       otherwise bin-log with error code cleared.
+     */
+    write_bin_log(thd, !something_wrong, thd->query, thd->query_length);
+  }
 
-  send_ok(thd);
   VOID(pthread_mutex_unlock(&LOCK_open));
+  
+  if (something_wrong)
+  {
+    DBUG_RETURN(TRUE);
+  }
+  send_ok(thd);
   DBUG_RETURN(FALSE);
 }