Merge endora.local:/Users/davi/mysql/bugs/31850-5.1

into  endora.local:/Users/davi/mysql/mysql-5.1-runtime

sql/sql_connect.cc

@@ -318,16 +318,19 @@ check_user(THD *thd, enum enum_server_command command,
   DBUG_ENTER("check_user");
   LEX_STRING db_str= { (char *) db, db ? strlen(db) : 0 };
 
+  /*
+    Clear thd->db as it points to something, that will be freed when
+    connection is closed. We don't want to accidentally free a wrong
+    pointer if connect failed. Also in case of 'CHANGE USER' failure,
+    current database will be switched to 'no database selected'.
+  */
+  thd->reset_db(NULL, 0);
+
 #ifdef NO_EMBEDDED_ACCESS_CHECKS
   thd->main_security_ctx.master_access= GLOBAL_ACLS;       // Full rights
   /* Change database if necessary */
   if (db && db[0])
   {
-    /*
-      thd->db is saved in caller and needs to be freed by caller if this
-      function returns 0
-    */
-    thd->reset_db(NULL, 0);
     if (mysql_change_db(thd, &db_str, FALSE))
       DBUG_RETURN(1);
   }
@@ -358,14 +361,6 @@ check_user(THD *thd, enum enum_server_command command,
     DBUG_RETURN(1);
   }
 
-  /*
-    Clear thd->db as it points to something, that will be freed when 
-    connection is closed. We don't want to accidentally free a wrong pointer
-    if connect failed. Also in case of 'CHANGE USER' failure, current
-    database will be switched to 'no database selected'.
-  */
-  thd->reset_db(NULL, 0);
-
   USER_RESOURCES ur;
   int res= acl_getroot(thd, &ur, passwd, passwd_len);
 #ifndef EMBEDDED_LIBRARY

sql/sql_parse.cc

@@ -911,6 +911,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
 
     /* Clear variables that are allocated */
     thd->user_connect= 0;
+    thd->security_ctx->priv_user= thd->security_ctx->user;
     res= check_user(thd, COM_CHANGE_USER, passwd, passwd_len, db, FALSE);
 
     if (res)
@@ -928,8 +929,8 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
       if (save_user_connect)
 	decrease_user_connections(save_user_connect);
 #endif /* NO_EMBEDDED_ACCESS_CHECKS */
-      x_free((uchar*) save_db);
-      x_free((uchar*)  save_security_ctx.user);
+      x_free(save_db);
+      x_free(save_security_ctx.user);
 
       if (cs_number)
       {