Bug#46958: Assertion in Diagnostics_area::set_ok_status, 
trigger, merge table
            
The problem with break statements is that they have very
local effects. Hence a break statement within the inner loop
of a nested-loops join caused execution to proceed to the
next table even though a serious error occurred. The problem
was fixed by breaking out the inner loop into its own
method. The change empowers all errors to terminate the
execution.
            
The errors that will now halt multi-DELETE execution
altogether are 
  - triggers returning errors
  - handler errors
  - server being killed


mysql-test/r/delete.result:
  Bug#46958: Test result.
mysql-test/t/delete.test:
  Bug#46958: Test case.
sql/sql_class.h:
  Bug#46958: New method declaration.
sql/sql_delete.cc:
  Bug#46958: New method implementation.

mysql-test/r/delete.result

@@ -279,3 +279,48 @@ ERROR 42000: Incorrect number of arguments for FUNCTION test.f1; expected 0, got
 DROP TABLE t1;
 DROP FUNCTION f1;
 End of 5.0 tests
+#
+# Bug#46958: Assertion in Diagnostics_area::set_ok_status, trigger, 
+# merge table
+#
+CREATE TABLE t1 ( a INT );
+CREATE TABLE t2 ( a INT );
+CREATE TABLE t3 ( a INT );
+INSERT INTO t1 VALUES (1), (2);
+INSERT INTO t2 VALUES (1), (2);
+INSERT INTO t3 VALUES (1), (2);
+CREATE TRIGGER tr1 BEFORE DELETE ON t2
+FOR EACH ROW INSERT INTO no_such_table VALUES (1);
+DELETE t1, t2, t3 FROM t1, t2, t3;
+ERROR 42S02: Table 'test.no_such_table' doesn't exist
+SELECT * FROM t1;
+a
+SELECT * FROM t2;
+a
+1
+2
+SELECT * FROM t3;
+a
+1
+2
+DROP TABLE t1, t2, t3;
+CREATE TABLE t1 ( a INT );
+CREATE TABLE t2 ( a INT );
+CREATE TABLE t3 ( a INT );
+INSERT INTO t1 VALUES (1), (2);
+INSERT INTO t2 VALUES (1), (2);
+INSERT INTO t3 VALUES (1), (2);
+CREATE TRIGGER tr1 AFTER DELETE ON t2
+FOR EACH ROW INSERT INTO no_such_table VALUES (1);
+DELETE t1, t2, t3 FROM t1, t2, t3;
+ERROR 42S02: Table 'test.no_such_table' doesn't exist
+SELECT * FROM t1;
+a
+SELECT * FROM t2;
+a
+2
+SELECT * FROM t3;
+a
+1
+2
+DROP TABLE t1, t2, t3;

mysql-test/t/delete.test

@@ -292,3 +292,47 @@ DROP TABLE t1;
 DROP FUNCTION f1;
 
 --echo End of 5.0 tests
+
+--echo #
+--echo # Bug#46958: Assertion in Diagnostics_area::set_ok_status, trigger, 
+--echo # merge table
+--echo #
+CREATE TABLE t1 ( a INT );
+CREATE TABLE t2 ( a INT );
+CREATE TABLE t3 ( a INT );
+
+INSERT INTO t1 VALUES (1), (2);
+INSERT INTO t2 VALUES (1), (2);
+INSERT INTO t3 VALUES (1), (2);
+
+CREATE TRIGGER tr1 BEFORE DELETE ON t2
+FOR EACH ROW INSERT INTO no_such_table VALUES (1);
+
+--error ER_NO_SUCH_TABLE
+DELETE t1, t2, t3 FROM t1, t2, t3;
+
+SELECT * FROM t1;
+SELECT * FROM t2;
+SELECT * FROM t3;
+
+DROP TABLE t1, t2, t3;
+
+CREATE TABLE t1 ( a INT );
+CREATE TABLE t2 ( a INT );
+CREATE TABLE t3 ( a INT );
+
+INSERT INTO t1 VALUES (1), (2);
+INSERT INTO t2 VALUES (1), (2);
+INSERT INTO t3 VALUES (1), (2);
+
+CREATE TRIGGER tr1 AFTER DELETE ON t2
+FOR EACH ROW INSERT INTO no_such_table VALUES (1);
+
+--error ER_NO_SUCH_TABLE
+DELETE t1, t2, t3 FROM t1, t2, t3;
+
+SELECT * FROM t1;
+SELECT * FROM t2;
+SELECT * FROM t3;
+
+DROP TABLE t1, t2, t3;

sql/sql_class.h

@@ -2907,7 +2907,8 @@ public:
   bool send_data(List<Item> &items);
   bool initialize_tables (JOIN *join);
   void send_error(uint errcode,const char *err);
-  int  do_deletes();
+  int do_deletes();
+  int do_table_deletes(TABLE *table, bool ignore);
   bool send_eof();
   virtual void abort();
 };

sql/sql_delete.cc

@@ -860,22 +860,19 @@ void multi_delete::abort()
 
 
 
-/*
+/**
   Do delete from other tables.
-  Returns values:
-	0 ok
-	1 error
+
+  @retval 0 ok
+  @retval 1 error
+
+  @todo Is there any reason not use the normal nested-loops join? If not, and
+  there is no documentation supporting it, this method and callee should be
+  removed and there should be hooks within normal execution.
 */
 
 int multi_delete::do_deletes()
 {
-  int local_error= 0, counter= 0, tmp_error;
-  bool will_batch;
-  /*
-    If the IGNORE option is used all non fatal errors will be translated
-    to warnings and we should not break the row-by-row iteration
-  */
-  bool ignore= thd->lex->current_select->no_error;
   DBUG_ENTER("do_deletes");
   DBUG_ASSERT(do_delete);
 
@@ -886,79 +883,108 @@ int multi_delete::do_deletes()
   table_being_deleted= (delete_while_scanning ? delete_tables->next_local :
                         delete_tables);
  
-  for (; table_being_deleted;
+  for (uint counter= 0; table_being_deleted;
        table_being_deleted= table_being_deleted->next_local, counter++)
   { 
-    ha_rows last_deleted= deleted;
     TABLE *table = table_being_deleted->table;
     if (tempfiles[counter]->get(table))
+      DBUG_RETURN(1);
+
+    int local_error= 
+      do_table_deletes(table, thd->lex->current_select->no_error);
+
+    if (thd->killed && !local_error)
+      DBUG_RETURN(1);
+
+    if (local_error == -1)				// End of file
+      local_error = 0;
+
+    if (local_error)
+      DBUG_RETURN(local_error);
+  }
+  DBUG_RETURN(0);
+}
+
+
+/**
+   Implements the inner loop of nested-loops join within multi-DELETE
+   execution.
+
+   @param table The table from which to delete.
+
+   @param ignore If used, all non fatal errors will be translated
+   to warnings and we should not break the row-by-row iteration.
+
+   @return Status code
+
+   @retval  0 All ok.
+   @retval  1 Triggers or handler reported error.
+   @retval -1 End of file from handler.
+*/
+int multi_delete::do_table_deletes(TABLE *table, bool ignore)
+{
+  int local_error= 0;
+  READ_RECORD info;
+  ha_rows last_deleted= deleted;
+  DBUG_ENTER("do_deletes_for_table");
+  init_read_record(&info, thd, table, NULL, 0, 1, FALSE);
+  /*
+    Ignore any rows not found in reference tables as they may already have
+    been deleted by foreign key handling
+  */
+  info.ignore_not_found_rows= 1;
+  bool will_batch= !table->file->start_bulk_delete();
+  while (!(local_error= info.read_record(&info)) && !thd->killed)
+  {
+    if (table->triggers &&
+        table->triggers->process_triggers(thd, TRG_EVENT_DELETE,
+                                          TRG_ACTION_BEFORE, FALSE))
     {
-      local_error=1;
+      local_error= 1;
       break;
     }
-
-    READ_RECORD	info;
-    init_read_record(&info, thd, table, NULL, 0, 1, FALSE);
+      
+    local_error= table->file->ha_delete_row(table->record[0]);
+    if (local_error && !ignore)
+    {
+      table->file->print_error(local_error, MYF(0));
+      break;
+    }
+      
     /*
-      Ignore any rows not found in reference tables as they may already have
-      been deleted by foreign key handling
+      Increase the reported number of deleted rows only if no error occurred
+      during ha_delete_row.
+      Also, don't execute the AFTER trigger if the row operation failed.
     */
-    info.ignore_not_found_rows= 1;
-    will_batch= !table->file->start_bulk_delete();
-    while (!(local_error=info.read_record(&info)) && !thd->killed)
+    if (!local_error)
     {
+      deleted++;
       if (table->triggers &&
           table->triggers->process_triggers(thd, TRG_EVENT_DELETE,
-                                            TRG_ACTION_BEFORE, FALSE))
+                                            TRG_ACTION_AFTER, FALSE))
       {
         local_error= 1;
         break;
       }
-
-      local_error= table->file->ha_delete_row(table->record[0]);
-      if (local_error && !ignore)
-      {
-        table->file->print_error(local_error,MYF(0));
-        break;
-      }
-
-      /*
-        Increase the reported number of deleted rows only if no error occurred
-        during ha_delete_row.
-        Also, don't execute the AFTER trigger if the row operation failed.
-      */
-      if (!local_error)
-      {
-        deleted++;
-        if (table->triggers &&
-            table->triggers->process_triggers(thd, TRG_EVENT_DELETE,
-                                              TRG_ACTION_AFTER, FALSE))
-        {
-          local_error= 1;
-          break;
-        }
-      }
     }
-    if (will_batch && (tmp_error= table->file->end_bulk_delete()))
+  }
+  if (will_batch)
+  {
+    int tmp_error= table->file->end_bulk_delete();
+    if (tmp_error && !local_error)
     {
-      if (!local_error)
-      {
-        local_error= tmp_error;
-        table->file->print_error(local_error,MYF(0));
-      }
+      local_error= tmp_error;
+      table->file->print_error(local_error, MYF(0));
     }
-    if (last_deleted != deleted && !table->file->has_transactions())
-      thd->transaction.stmt.modified_non_trans_table= TRUE;
-    end_read_record(&info);
-    if (thd->killed && !local_error)
-      local_error= 1;
-    if (local_error == -1)				// End of file
-      local_error = 0;
   }
+  if (last_deleted != deleted && !table->file->has_transactions())
+    thd->transaction.stmt.modified_non_trans_table= TRUE;
+
+  end_read_record(&info);
+
   DBUG_RETURN(local_error);
 }
 
-
 /*
   Send ok to the client