Fixes during review of new pushed code:

Remove wrong fix for Bug#14397 - OPTIMIZE TABLE with an open HANDLER causes a crash
Safety fix for bug #13855 "select distinct with group by caused server crash"


client/mysqlimport.c:
  Remove not used variable
myisam/myisam_ftdump.c:
  Fixed compiler warning
sql/item_cmpfunc.cc:
  Removed compiler warning
sql/sql_handler.cc:
  Remove wrong fix for Bug#14397 - OPTIMIZE TABLE with an open HANDLER causes a crash.
  It's better to let mysql_lock_tables reopen the TABLE object in case of OPTIMIZE TABLE and fix items AFTER mysql_lock_table() instead of before
sql/sql_select.cc:
  Safety fix for bug #13855 "select distinct with group by caused server crash"
  The previous patch only removed the symptomps, this fix removed the cause of the problem
  (Which was that not all hidden_fields was stored in the temporary table)

3 files changed, 21 insertions, 36 deletions

diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 107a17815ae..db6c4d9789b 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -659,7 +659,7 @@ bool
 Item_func_nullif::is_null()
 {
   if (!(this->*cmp_func)())
-    return null_value=1;
+    return (null_value= 1);
   return 0;
 }
 
diff --git a/sql/sql_handler.cc b/sql/sql_handler.cc
index 28e94d1a477..58b75e667b5 100644
--- a/sql/sql_handler.cc
+++ b/sql/sql_handler.cc
@@ -380,27 +380,6 @@ int mysql_ha_read(THD *thd, TABLE_LIST *tables,
     DBUG_PRINT("info-in-hash",("'%s'.'%s' as '%s' tab %p",
                                hash_tables->db, hash_tables->real_name,
                                hash_tables->alias, table));
-    /* Table might have been flushed. */
-    if (table && (table->version != refresh_version))
-    {
-      /*
-        We must follow the thd->handler_tables chain, as we need the
-        address of the 'next' pointer referencing this table
-        for close_thread_table().
-      */
-      for (table_ptr= &(thd->handler_tables);
-           *table_ptr && (*table_ptr != table);
-           table_ptr= &(*table_ptr)->next)
-      {}
-      VOID(pthread_mutex_lock(&LOCK_open));
-      if (close_thread_table(thd, table_ptr))
-      {
-        /* Tell threads waiting for refresh that something has happened */
-        VOID(pthread_cond_broadcast(&COND_refresh));
-      }
-      VOID(pthread_mutex_unlock(&LOCK_open));
-      table= hash_tables->table= NULL;
-    }
     if (!table)
     {
       /*
@@ -447,11 +426,16 @@ int mysql_ha_read(THD *thd, TABLE_LIST *tables,
   }
   tables->table=table;
 
+  HANDLER_TABLES_HACK(thd);
+  lock= mysql_lock_tables(thd, &tables->table, 1, 0);
+  HANDLER_TABLES_HACK(thd);
+
+  if (!lock)
+    goto err0; // mysql_lock_tables() printed error message already
+
   if (cond && cond->fix_fields(thd,tables))
     goto err0;
 
-  table->file->init_table_handle_for_HANDLER(); // Only InnoDB requires it
-
   if (keyname)
   {
     if ((keyno=find_type(keyname, &table->keynames, 1+2)-1)<0)
@@ -462,6 +446,11 @@ int mysql_ha_read(THD *thd, TABLE_LIST *tables,
     }
     table->file->index_init(keyno);
   }
+ 
+  byte *key;
+  uint key_len;
+  LINT_INIT(key); 
+  LINT_INIT(key_len); 
 
   if (insert_fields(thd,tables,tables->db,tables->alias,&it))
     goto err0;
@@ -469,17 +458,6 @@ int mysql_ha_read(THD *thd, TABLE_LIST *tables,
   select_limit+=offset_limit;
   send_fields(thd,list,1);
 
-  HANDLER_TABLES_HACK(thd);
-  lock= mysql_lock_tables(thd, &tables->table, 1, 0);
-  HANDLER_TABLES_HACK(thd);
-  
-  byte *key;
-  uint key_len;
-  LINT_INIT(key); 
-  LINT_INIT(key_len); 
-  if (!lock)
-     goto err0; // mysql_lock_tables() printed error message already
-
   table->file->init_table_handle_for_HANDLER(); // Only InnoDB requires it
 
   for (num_rows=0; num_rows < select_limit; )
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 6dd68a60f88..32658f92416 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -4082,7 +4082,14 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
       *(reg_field++) =new_field;
     }
     if (!--hidden_field_count)
+    {
       hidden_null_count=null_count;
+      /*
+        We need to update hidden_field_count as we may have stored group
+        functions with constant arguments
+      */
+      param->hidden_field_count= (uint) (reg_field - table->field);
+    }
   }
   DBUG_ASSERT(field_count >= (uint) (reg_field - table->field));
   field_count= (uint) (reg_field - table->field);
@@ -4270,7 +4277,7 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
     }
   }
 
-  if (distinct)
+  if (distinct && field_count != param->hidden_field_count)
   {
     /*
       Create an unique key or an unique constraint over all columns