Fix bug #9728 decreased functionality in "on duplicate key update"

Remove changes made by bug fix #8147. They strips list of insert_table_list to
only insert table, which results in error reported in bug #9728.
Added flag to Item to resolve ambigous fields reported in bug #8147.

mysql-test/r/insert_select.result

@@ -634,3 +634,18 @@ ff1	ff2
 1	2
 2	1
 drop table t1, t2;
+create table t1 (a int unique);
+create table t2 (a int, b int);
+insert into t1 values (1),(2);
+insert into t2 values (1,2);
+select * from t1;
+a
+1
+2
+insert into t1 select t2.a from t2 on duplicate key update a= a + t2.b;
+select * from t1;
+a
+2
+3
+drop table t1;
+drop table t2;

mysql-test/t/insert_select.test

@@ -175,3 +175,17 @@ insert into t1 values (1),(1),(2);
 insert into t2(ff1) select f1 from t1 on duplicate key update ff2=ff2+1;
 select * from t2;
 drop table t1, t2;
+#
+# BUGS #9728 - 'Decreased functionality in "on duplicate key update"' 
+#      #8147 - 'a column proclaimed ambigous in INSERT ... SELECT .. ON
+#      DUPLICATE'
+#
+create table t1 (a int unique);
+create table t2 (a int, b int);
+insert into t1 values (1),(2);
+insert into t2 values (1,2);
+select * from t1;
+insert into t1 select t2.a from t2 on duplicate key update a= a + t2.b;
+select * from t1;
+drop table t1;
+drop table t2; 

sql/item.cc

@@ -65,6 +65,7 @@ Item::Item():
 	place == IN_HAVING)
       thd->lex->current_select->select_n_having_items++;
   }
+  item_flags= 0;
 }
 
 /*
@@ -83,7 +84,8 @@ Item::Item(THD *thd, Item *item):
   unsigned_flag(item->unsigned_flag),
   with_sum_func(item->with_sum_func),
   fixed(item->fixed),
-  collation(item->collation)
+  collation(item->collation),
+  item_flags(item->item_flags)
 {
   next= thd->free_list;				// Put in free list
   thd->free_list= this;

sql/item.h

@@ -107,6 +107,11 @@ class DTCollation {
 
 typedef bool (Item::*Item_processor)(byte *arg);
 
+/*
+ See comments for sql_yacc.yy: insert_update_elem rule
+ */
+#define MY_ITEM_PREFER_1ST_TABLE 1
+
 class Item {
   Item(const Item &);			/* Prevent use of these */
   void operator=(Item &);
@@ -142,6 +147,7 @@ class Item {
   my_bool with_sum_func;
   my_bool fixed;                        /* If item fixed with fix_fields */
   DTCollation collation;
+  uint8 item_flags;		/* Flags on how item should be processed */
 
   // alloc & destruct is done as start of select using sql_alloc
   Item();
@@ -327,6 +333,11 @@ class Item {
     cleanup();
     delete this;
   }
+  virtual bool set_flags_processor(byte *args)
+  {
+    this->item_flags|= *((uint8*)args);
+    return true;
+  }
 };
 
 

sql/sql_base.cc

@@ -2086,7 +2086,8 @@ find_field_in_tables(THD *thd, Item_ident *item, TABLE_LIST *tables,
     return (Field*) 0;
   }
   bool allow_rowid= tables && !tables->next;	// Only one table
-  for (; tables ; tables=tables->next)
+  uint table_idx= 0;
+  for (; tables ; tables=tables->next, table_idx++)
   {
     if (!tables->table)
     {
@@ -2114,7 +2115,9 @@ find_field_in_tables(THD *thd, Item_ident *item, TABLE_LIST *tables,
 			name,thd->where);
 	return (Field*) 0;
       }
-      found=field;
+      found= field;
+      if (table_idx == 0 && item->item_flags & MY_ITEM_PREFER_1ST_TABLE) 
+        break;
     }
   }
   if (found)

sql/sql_parse.cc

@@ -2856,17 +2856,14 @@ mysql_execute_command(THD *thd)
     if ((res= open_and_lock_tables(thd, tables)))
       break;
       
-    TABLE *table= tables->table;
     /* Skip first table, which is the table we are inserting in */
     select_lex->table_list.first= (byte*) first_local_table->next;
-    tables= (TABLE_LIST *) select_lex->table_list.first;
-    first_local_table->next= 0;
     
     if (!(res= mysql_prepare_insert(thd, tables, first_local_table, 
-				    table, lex->field_list, 0,
+				    tables->table, lex->field_list, 0,
 				    lex->update_list, lex->value_list,
 				    lex->duplicates)) &&
-        (result= new select_insert(table, &lex->field_list,
+        (result= new select_insert(tables->table, &lex->field_list,
 				   &lex->update_list, &lex->value_list,
                                    lex->duplicates, lex->ignore)))
     {
@@ -2879,7 +2876,7 @@ mysql_execute_command(THD *thd)
       /* revert changes for SP */
       lex->select_lex.resolve_mode= SELECT_LEX::INSERT_MODE;
       delete result;
-      table->insert_values= 0;
+      tables->table->insert_values= 0;
       if (thd->net.report_error)
         res= -1;
     }

sql/sql_yacc.yy

@@ -4239,9 +4239,24 @@ insert_update_elem:
 	simple_ident equal expr_or_default
 	{
 	  LEX *lex= Lex;
+          uint8 tmp= MY_ITEM_PREFER_1ST_TABLE;
 	  if (lex->update_list.push_back($1) || 
 	      lex->value_list.push_back($3))
 	    YYABORT;
+          /* 
+            INSERT INTO a1(a) SELECT b1.a FROM b1 ON DUPLICATE KEY 
+              UPDATE a= a + b1.b
+   
+            Set MY_ITEM_PREFER_1ST_TABLE flag to $1 and $3 items
+            to prevent find_field_in_tables() doing further item searching 
+            if it finds item occurence in first table in insert_table_list. 
+            This allows to avoid ambiguity in resolving 'a' field in 
+            example above.
+          */
+          $1->walk(&Item::set_flags_processor,
+                  (byte *) &tmp);
+          $3->walk(&Item::set_flags_processor,
+                  (byte *) &tmp);
 	};
 
 opt_low_priority: