protect against empty-string parent str

direct/src/distributed/DistributedNode.py

@@ -93,8 +93,8 @@ class DistributedNode(DistributedObject.DistributedObject, NodePath):
     def setParentStr(self, parentTokenStr):
         assert self.notify.debug('setParentStr: %s' % parentTokenStr)
         assert self.notify.debug('isGenerated: %s' % self.isGenerated())
-        self.do_setParent(parentTokenStr)
         if len(parentTokenStr) > 0:
+            self.do_setParent(parentTokenStr)
             self.gotStringParentToken = 1
 
     def setParent(self, parentToken):

direct/src/distributed/DistributedNodeAI.py

@@ -60,7 +60,8 @@ class DistributedNodeAI(DistributedObjectAI.DistributedObjectAI, NodePath):
 
     def setParentStr(self, parentToken):
         self.notify.debug('setParentStr(%s): %s' % (self.doId, parentToken))
-        self.do_setParent(parentToken)
+        if len(parentTokenStr) > 0:
+            self.do_setParent(parentToken)
 
     def setParent(self, parentToken):
         self.notify.debug('setParent(%s): %s' % (self.doId, parentToken))

direct/src/distributed/DistributedNodeUD.py

@@ -27,7 +27,8 @@ class DistributedNodeUD(DistributedObjectUD):
 
     def setParentStr(self, parentToken):
         self.notify.debugCall()
-        self.do_setParent(parentToken)
+        if len(parentTokenStr) > 0:
+            self.do_setParent(parentToken)
 
     def setParent(self, parentToken):
         self.notify.debugCall()