René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Incorrect fetch from the OD objects due to their `__len__` method","articleBody":"As I was looking at #436 I did some tracing and noticed that `ODVariable.__len__` is called many more times than expected and I uncovered a side effect:\n\nIn `ObjectDictionary.__getitem__()` we have in L136 the line `item = self.names.get(index) or self.indices.get(index)`. What happens here is that python looks up the index from `self.names` first. When it has found an object, it evaluates if this object is false, and it does so by running its `__len__()` function. That it will call `ODVariable.__len__`, `ODArray.__len__` or `ODRecord.__len__`. If this happens to be 0, the object fails the test it moves on to the next step, potentially returning `None`.\n\nReference: https://docs.python.org/3/library/stdtypes.html#truth-value-testing\n\nI assume we might be interested in fixing this?\n\nhttps://github.com/canopen-python/canopen/blob/7ddb19b2ca7b7a85b9cef3090249b00293dd4b4a/canopen/objectdictionary/__init__.py#L132-L142\n","author":{"url":"https://github.com/sveinse","@type":"Person","name":"sveinse"},"datePublished":"2025-06-14T22:07:18.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/588/canopen/issues/588"}