diff -r 8f81d6f4047f -r 98ee3dd5bab4 mercurial/posix.py
--- a/mercurial/posix.py	Fri Apr 08 17:47:58 2011 +0300
+++ b/mercurial/posix.py	Wed Apr 06 18:09:43 2011 +0200
@@ -147,6 +147,11 @@
     except (OSError, AttributeError):
         return False
 
+def checkosfilename(path):
+    '''Check that the base-relative path is a valid filename on this platform.
+    Returns None if the path is ok, or a UI string describing the problem.'''
+    pass # on posix platforms, every path is ok
+
 def set_binary(fd):
     pass