better handling of unicode paths in errors

fs/errors.py

@@ -31,7 +31,12 @@ class FSError(Exception):
         self.details = details
 
     def __str__(self):
-        return unicode(self).encode(sys.getfilesystemencoding())
+        keys = {}
+        for k,v in self.__dict__.iteritems():
+            if isinstance(v,unicode):
+                v = v.encode(sys.getfilesystemencoding())
+            keys[k] = v
+        return str(self.msg % keys)
 
     def __unicode__(self):
         keys = dict((k,v) for k,v in self.__dict__.iteritems())

fs/wrapfs.py

@@ -252,7 +252,7 @@ def wrap_fs_methods(decorator,cls=None,exclude=[]):
     methods = ("open","exists","isdir","isfile","listdir","makedir","remove",
                "setcontents","removedir","rename","getinfo","copy","move",
                "copydir","movedir","close","getxattr","setxattr","delxattr",
-               "listxattrs")
+               "listxattrs","getsyspath")
                
     def apply_decorator(cls):
         for method_name in methods: