Bug in native user32

[Jacek Caban]

Hello.

Fixing MSHTML tests I found a bug in Windows.
In tests I passed const WNDCLASSEX, to RegisterClassEx
what should work as its declaration is:

ATOM WINAPI RegisterClassExW(const WNDCLASSEXW *);

Changing passed WNDCLASS to nonconst makes it
works. I wrote small tests (attached) showing that if hInstance
of WNDCLASSEX is NULL, RegisterClassEx sets it to
GetModuleHandle(NULL). It, of course, couses segmentation
fault in case CMASSWNDEX is const. This problem seams
to happen on XP, NT 4, 2k and 2k3. So the question is if
we should clone this bug? Some applications may expect
it, but other may crash. They will crash on Windows anyway...
Or we should mark test as todo_wine and change it
if we found application that depend on it?

Thanks,
    Jacek
-------------- next part --------------
Index: dlls/user/tests/class.c
===================================================================
RCS file: /home/wine/wine/dlls/user/tests/class.c,v
retrieving revision 1.19
diff -u -p -r1.19 class.c
--- dlls/user/tests/class.c	15 Jun 2005 10:21:19 -0000	1.19
+++ dlls/user/tests/class.c	25 Jul 2005 16:14:10 -0000
@@ -301,6 +301,15 @@ static void test_instances(void)
     HINSTANCE user32 = GetModuleHandleA("user32");
     HINSTANCE main_module = GetModuleHandleA(NULL);
 
+    WNDCLASSEXA clsex = {
+        sizeof(WNDCLASSEXW),
+        0,
+        ClassTest_WndProc,
+        0, 0, NULL, NULL, NULL, NULL, NULL,
+        "const_test",
+        NULL
+    };
+
     memset( &cls, 0, sizeof(cls) );
     cls.style         = CS_HREDRAW | CS_VREDRAW;
     cls.lpfnWndProc   = ClassTest_WndProc;
@@ -436,6 +445,10 @@ static void test_instances(void)
     ok( !GetClassInfo( 0, name, &wc ), "Class found with null instance\n" );
     ok( GetLastError() == ERROR_CLASS_DOES_NOT_EXIST, "Wrong error code %ld\n", GetLastError() );
     ok( UnregisterClassA( name, 0 ), "Unregister failed for null instance\n" );
+
+    ok( RegisterClassExA( &clsex), "RegisterClassExA failed\n");
+    ok( clsex.hInstance == GetModuleHandle(NULL), "hInstance=%08lx\n, expected %08lx\n",
+            clsex.hInstance, GetModuleHandle(NULL));
 
     /* registering for user32 always fails */
     cls.lpszMenuName = "user32";