On windows, os.chdir given unicode was not working if GetCurrentDirectoryW

returned a path longer than MAX_PATH. (But It's doubtful this code path is
really executed because I cannot move to such directory on win2k)

Misc/NEWS

@@ -12,6 +12,10 @@ What's New in Python 2.7 alpha 1
 Core and Builtins
 -----------------
 
+- On windows, os.chdir given unicode was not working if GetCurrentDirectoryW
+  returned a path longer than MAX_PATH. (But It's doubtful this code path is
+  really executed because I cannot move to such directory on win2k)
+
 - Issue #4069: When set.remove(element) is used with a set element, the element
   is temporarily replaced with an equivalent frozenset.  But the eventual
   KeyError would always report the empty frozenset([]) as the missing key. Now

Modules/posixmodule.c

@@ -726,11 +726,14 @@ win32_wchdir(LPCWSTR path)
 	if (!result)
 		return FALSE;
 	if (result > MAX_PATH+1) {
-		new_path = malloc(result);
+		new_path = malloc(result * sizeof(wchar_t));
 		if (!new_path) {
 			SetLastError(ERROR_OUTOFMEMORY);
 			return FALSE;
 		}
+		result = GetCurrentDirectoryW(result, new_path);
+		if (!result)
+			return FALSE;
 	}
 	if (wcsncmp(new_path, L"\\\\", 2) == 0 ||
 	    wcsncmp(new_path, L"//", 2) == 0)