Fix for bugs:

 #5860 "Multi-table UPDATE does not activate update triggers"
 #6812 "Triggers are not activated for INSERT ... SELECT"
 #8755 "Trigger is not activated by LOAD DATA".
This patch also implements proper handling of triggers for special forms
of insert like REPLACE or INSERT ... ON DUPLICATE KEY UPDATE. 
Also now we don't call after trigger in case when we have failed to
inserted/update or delete row. Trigger failure should stop statement
execution.

I have not properly tested handling of errors which happen inside of
triggers in this patch, since it is simplier to do this once we will be
able to access tables from triggers.

1 files changed, 24 insertions, 21 deletions

diff --git a/sql/sql_trigger.cc b/sql/sql_trigger.cc
index 670c618bec5..95524a6dfbf 100644
--- a/sql/sql_trigger.cc
+++ b/sql/sql_trigger.cc
@@ -85,7 +85,7 @@ bool mysql_create_or_drop_trigger(THD *thd, TABLE_LIST *tables, bool create)
       DBUG_RETURN(TRUE);
     }
 
-    if (!(table->triggers= new (&table->mem_root) Table_triggers_list()))
+    if (!(table->triggers= new (&table->mem_root) Table_triggers_list(table)))
       DBUG_RETURN(TRUE);
   }
 
@@ -190,17 +190,16 @@ bool Table_triggers_list::create_trigger(THD *thd, TABLE_LIST *tables)
     to other tables from trigger we won't be able to catch changes in other
     tables...
 
-    To simplify code a bit we have to create Fields for accessing to old row
-    values if we have ON UPDATE trigger.
+    Since we don't plan to access to contents of the fields it does not
+    matter that we choose for both OLD and NEW values the same versions
+    of Field objects here.
   */
-  if (!old_field && lex->trg_chistics.event == TRG_EVENT_UPDATE &&
-      prepare_old_row_accessors(table))
-    return 1;
+  old_field= new_field= table->field;
 
   for (trg_field= (Item_trigger_field *)(lex->trg_table_fields.first);
        trg_field; trg_field= trg_field->next_trg_field)
   {
-    trg_field->setup_field(thd, table, lex->trg_chistics.event);
+    trg_field->setup_field(thd, table);
     if (!trg_field->fixed &&
         trg_field->fix_fields(thd, (TABLE_LIST *)0, (Item **)0))
       return 1;
@@ -318,34 +317,35 @@ Table_triggers_list::~Table_triggers_list()
     for (int j= 0; j < 2; j++)
       delete bodies[i][j];
 
-  if (old_field)
-    for (Field **fld_ptr= old_field; *fld_ptr; fld_ptr++)
+  if (record1_field)
+    for (Field **fld_ptr= record1_field; *fld_ptr; fld_ptr++)
       delete *fld_ptr;
 }
 
 
 /*
-  Prepare array of Field objects which will represent OLD.* row values in
-  ON UPDATE trigger (by referencing to record[1] instead of record[0]).
+  Prepare array of Field objects referencing to TABLE::record[1] instead
+  of record[0] (they will represent OLD.* row values in ON UPDATE trigger
+  and in ON DELETE trigger which will be called during REPLACE execution).
 
   SYNOPSIS
-    prepare_old_row_accessors()
+    prepare_record1_accessors()
       table - pointer to TABLE object for which we are creating fields.
 
   RETURN VALUE
     False - success
     True  - error
 */
-bool Table_triggers_list::prepare_old_row_accessors(TABLE *table)
+bool Table_triggers_list::prepare_record1_accessors(TABLE *table)
 {
   Field **fld, **old_fld;
 
-  if (!(old_field= (Field **)alloc_root(&table->mem_root,
-                                        (table->s->fields + 1) *
-                                        sizeof(Field*))))
+  if (!(record1_field= (Field **)alloc_root(&table->mem_root,
+                                            (table->s->fields + 1) *
+                                            sizeof(Field*))))
     return 1;
 
-  for (fld= table->field, old_fld= old_field; *fld; fld++, old_fld++)
+  for (fld= table->field, old_fld= record1_field; *fld; fld++, old_fld++)
   {
     /*
       QQ: it is supposed that it is ok to use this function for field
@@ -406,7 +406,7 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
                  parser->type()->length))
     {
       Table_triggers_list *triggers=
-        new (&table->mem_root) Table_triggers_list();
+        new (&table->mem_root) Table_triggers_list(table);
 
       if (!triggers)
         DBUG_RETURN(1);
@@ -417,8 +417,11 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
 
       table->triggers= triggers;
 
-      /* TODO: This could be avoided if there is no ON UPDATE trigger. */
-      if (triggers->prepare_old_row_accessors(table))
+      /*
+        TODO: This could be avoided if there is no triggers
+              for UPDATE and DELETE.
+      */
+      if (triggers->prepare_record1_accessors(table))
         DBUG_RETURN(1);
 
       List_iterator_fast<LEX_STRING> it(triggers->definitions_list);
@@ -478,7 +481,7 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
                (Item_trigger_field *)(lex.trg_table_fields.first);
              trg_field;
              trg_field= trg_field->next_trg_field)
-          trg_field->setup_field(thd, table, lex.trg_chistics.event);
+          trg_field->setup_field(thd, table);
 
         lex_end(&lex);
       }