fix potential python 2 issue

Python 2 checks for __nonzero__(), not __bool__(). roverlay usually relies
explicit checks ("if obj.attr == $expected" or "obj.exists()" rather than
"if object:"), so this is not a major issue.

1 files changed, 8 insertions, 0 deletions

diff --git a/roverlay/util/objects.py b/roverlay/util/objects.py
index d14733e..9c73749 100644
--- a/roverlay/util/objects.py
+++ b/roverlay/util/objects.py
@@ -55,6 +55,8 @@ class SafeWeakRef ( weakref.ref ):
       return self.deref_unsafe() is not None
    # --- end of __bool__ (...) ---
 
+   __nonzero__ = __bool__
+
    def __repr__ ( self ):
       obj = self.deref_unsafe()
       if obj:
@@ -104,6 +106,8 @@ class NoneRef ( object ):
       return False
    # --- end of __bool__ (...) ---
 
+   __nonzero__ = __bool__
+
    def __repr__ ( self ):
       return "<NoneRef at 0x{:x}>".format ( id ( self ) )
    # --- end of __repr__ (...) ---
@@ -360,6 +364,10 @@ class ObjectView ( object ):
       return bool ( self.obj_ref )
    # --- end of __bool__ (...) ---
 
+   def __nonzero__ ( self ):
+      return self.__bool__()
+   # --- end of __nonzero__ (...) ---
+
    @abstractmethod
    def update ( self ):
       """Updates this view (collect data from the actual object etc.)."""