pyop3: ro_with_halos and rw_with_halos need broadcast (#27)

Author: ksagiyam

pyop3/buffer.py

@@ -214,6 +214,8 @@ def data_rw_with_halos(self):
 
         if not self._roots_valid:
             self._reduce_leaves_to_roots()
+        if not self._leaves_valid:
+            self._broadcast_roots_to_leaves()
 
         # modifying owned values invalidates ghosts
         self._leaves_valid = False
@@ -224,6 +226,8 @@ def data_rw_with_halos(self):
     def data_ro_with_halos(self):
         if not self._roots_valid:
             self._reduce_leaves_to_roots()
+        if not self._leaves_valid:
+            self._broadcast_roots_to_leaves()
         return readonly(self._data)
 
     @property