Bug #27811:

FORCE_INIT_OF_VARS was not defined for the 
 debug builds on Windows. This caused LINT_INIT
 macro to be defined as NOP and this triggers
 false alarms about use of uninitialized with
 the runtime libs of some Visual Studio versions.
 Fixed by defining FORCE_INIT_OF_VARS to match the
 state of the Windows

CMakeLists.txt

@@ -26,6 +26,10 @@ ADD_DEFINITIONS(-D WITH_MYISAM_STORAGE_ENGINE)
 ADD_DEFINITIONS(-D CMAKE_BUILD)
 ADD_DEFINITIONS(-D HAVE_YASSL)
 
+# Set debug options
+SET(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -DFORCE_INIT_OF_VARS")
+SET(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} -DFORCE_INIT_OF_VARS")
+
 SET (mysql_plugin_defs "${mysql_plugin_defs},builtin_myisam_plugin")
 
 

mysql-test/r/windows.result

@@ -12,3 +12,10 @@ Warnings:
 Warning	0	DATA DIRECTORY option ignored
 Warning	0	INDEX DIRECTORY option ignored
 drop table t1;
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 VALUES (1,1);
+EXPLAIN SELECT * FROM t1 WHERE b =  (SELECT max(2));
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+End of 5.0 tests.

mysql-test/t/windows.test

@@ -27,3 +27,11 @@ CREATE TABLE t1 ( `ID` int(6) ) data directory 'c:/tmp/' index directory 'c:/tmp
 drop table t1;
 
 # End of 4.1 tests
+
+#
+# Bug #27811: The variable 'join_tab' is being used without being defined
+#
+CREATE TABLE t1 (a int, b int); INSERT INTO t1 VALUES (1,1);
+EXPLAIN SELECT * FROM t1 WHERE b =  (SELECT max(2));
+
+--echo End of 5.0 tests.