fixed case when real length very close to calculated (BUG#5150)

mysql-test/r/view.result:
  tested problem when function name length close to ALIGN_SIZE
mysql-test/t/view.test:
  tested problem when function name length close to ALIGN_SIZE
sql/item_func.cc:
  fixed case when real length very close to calculated (less then ALIGN)

mysql-test/r/view.result

@@ -1176,3 +1176,10 @@ test.`f``1` ()
 5
 drop view v1;
 drop function `f``1`;
+create function x () returns int return 5;
+create view v1 as select x ();
+select * from v1;
+x ()
+5
+drop view v1;
+drop function x;

mysql-test/t/view.test

@@ -1116,3 +1116,12 @@ show create view v1;
 select * from v1;
 drop view v1;
 drop function `f``1`;
+
+#
+# tested problem when function name length close to ALIGN_SIZE
+#
+create function x () returns int return 5;
+create view v1 as select x ();
+select * from v1;
+drop view v1;
+drop function x;

sql/item_func.cc

@@ -3271,12 +3271,14 @@ const char *
 Item_func_sp::func_name() const
 {
   THD * thd= current_thd;
+  /* Calculate length to avoud reallocation of string for sure */
   uint len= ((m_name->m_db.length +
               m_name->m_name.length)*2 + //characters*quoting
              2 +                         // ` and `
              1 +                         // .
-             1);                         // end of string
-  String qname(alloc_root(&thd->mem_root, len), len,
+             1 +                         // end of string
+             ALIGN_SIZE(1));             // to avoid String reallocation
+  String qname((char *)alloc_root(&thd->mem_root, len), len,
                system_charset_info);
   qname.length(0);
   append_identifier(thd, &qname, m_name->m_db.str, m_name->m_db.length);