Members of a list become disassociated when you mutate them

[nickretallack]

Say you have a protocol buffer that contains a repeated element which in turn contains more repeated elements. If you mutate one of the repeated elements at the root, you're fine. However, if you mutate a repeated element that is a child of another repeated element, it becomes a different object from the one that's in its parent's list.

This demonstrates how the same object gets dissociated

nested_item = Top.items[0]
nested_item.items += (item,)
nested_item.items.length != Top.items[0].items.length

This quickly demonstrates the anomaly and how it eats data

length_before = Top.items[0].items.length
Top.items[0].items += (item,)
length_after = Top.items[0].items.length
length_before == length_after

[nickretallack]

I can work around the issue by recursively placing the new element into its parents' lists. This is a little awkward, but it works.