Fix 11 "fetch from view returns wrong data"

Wrong method for creating temporary field was choosen, which results in
sending int field with int header but lonlong data.

Test case is added to mysql_client_test.c because client library is required
to test the bug.



tests/mysql_client_test.c:
  Test case for bug#11111 "fetch from view returns wrong data"
sql/sql_select.cc:
  Fix bug #11111 "fetch from view returns wrong data"
sql/item.h:
  Fix bug #11111 "fetch from view returns wrong data"

sql/item.h

@@ -1352,7 +1352,13 @@ public:
   {
     (*ref)->save_in_field(result_field, no_conversions);
   }
-  Item *real_item() { return *ref; }
+  Item *real_item() {
+    Item *item= this;
+    do
+      item= *((Item_ref *)item)->ref;
+    while (item->type() == Item::REF_ITEM);
+    return item;
+  }
   bool walk(Item_processor processor, byte *arg)
   { return (*ref)->walk(processor, arg); }
   void print(String *str);

sql/sql_select.cc

@@ -7957,6 +7957,19 @@ Field *create_tmp_field(THD *thd, TABLE *table,Item *item, Item::Type type,
                                        modify_item ? (Item_field*) item : NULL,
                                        convert_blob_length);
   }
+  case Item::REF_ITEM:
+    if ( ((Item_ref*)item)->real_item()->type() == Item::FIELD_ITEM)
+    {
+      Item_field *field= (Item_field*) *((Item_ref*)item)->ref;
+      Field *new_field= create_tmp_field_from_field(thd, 
+                               (*from_field= field->field),
+                               item->name, table,
+                               NULL,
+                               convert_blob_length);
+      if (modify_item)
+        item->set_result_field(new_field);
+      return new_field;
+    }
   case Item::FUNC_ITEM:
   case Item::COND_ITEM:
   case Item::FIELD_AVG_ITEM:
@@ -7968,7 +7981,6 @@ Field *create_tmp_field(THD *thd, TABLE *table,Item *item, Item::Type type,
   case Item::REAL_ITEM:
   case Item::DECIMAL_ITEM:
   case Item::STRING_ITEM:
-  case Item::REF_ITEM:
   case Item::NULL_ITEM:
   case Item::VARBIN_ITEM:
     return create_tmp_field_from_item(thd, item, table, copy_func, modify_item,

tests/mysql_client_test.c

@@ -13145,6 +13145,48 @@ static void test_bug9643()
   myquery(rc);
 }
 
+/*
+  Bug#11111: fetch from view returns wrong data
+*/
+
+static void test_bug11111()
+{
+  MYSQL_STMT 	*stmt;
+  MYSQL_BIND	bind[2];
+  char		buf[2][20];
+  long		len[2];
+  int i;
+  const char * query = "SELECT DISTINCT f1,ff2 FROM v1";
+
+  mysql_query(mysql, "drop table if exists t1, t2, v1");
+  mysql_query(mysql, "create table t1 (f1 int, f2 int)");
+  mysql_query(mysql, "create table t2 (ff1 int, ff2 int)");
+  mysql_query(mysql, "create view v1 as select * from t1, t2 where f1=ff1");
+  mysql_query(mysql, "insert into t1 values (1,1), (2,2), (3,3)");
+  mysql_query(mysql, "insert into t2 values (1,1), (2,2), (3,3)");
+
+  stmt = mysql_stmt_init(mysql);
+
+  mysql_stmt_prepare(stmt, query, strlen(query));
+  mysql_stmt_execute(stmt);
+
+  for (i=0; i < 2; i++) {
+    memset(&bind[i], '\0', sizeof(MYSQL_BIND));
+    bind[i].buffer_type= MYSQL_TYPE_STRING;
+    bind[i].buffer= (gptr *)&buf[i];
+    bind[i].buffer_length= 20;
+    bind[i].length= &len[i];
+  } 
+
+  if (mysql_stmt_bind_result(stmt, bind))
+    printf("Error: %s\n", mysql_stmt_error(stmt));
+
+  mysql_stmt_fetch(stmt);
+  DIE_UNLESS(!strcmp(buf[1],"1"));	
+  mysql_stmt_close(stmt);
+  mysql_query(mysql, "drop table t1, t2, v1");
+}
+
 /*
   Check that proper cleanups are done for prepared statement when
   fetching thorugh a cursor.
@@ -13439,6 +13481,7 @@ static struct my_tests_st my_tests[]= {
   { "test_bug9478", test_bug9478 },
   { "test_bug9643", test_bug9643 },
   { "test_bug10729", test_bug10729 },
+  { "test_bug11111", test_bug11111 },
   { 0, 0 }
 };