Silent fail when trying to overwrite AttributeFrozenDict entry

[espenfl]

Upon modifying input namespaces, e.g.

some_namespace = self.inputs.some_namespace
some_namespace.some_param = some_thing

Where some_namespace is an AttributeFrozenDict no error is given. It makes development a bit cumbersome on the plugin side. Maybe we can eject an error when this happens instead of not setting it and continuing?

[sphuber]

This is happening within the define of a Process class? That is to say, the code snippet you wrote, is what you are typing in the define classmethod? Or somewhere else?

[espenfl]

This happens somewhere else.

[sphuber]

This class comes from plumpy. I guess you are describing the following behavior:

In [1]: from plumpy.utils import AttributesFrozendict

In [2]: d = AttributesFrozendict({'a': 1})

In [3]: d.a = 5

In [4]: d
Out[4]: <AttributesFrozendict {'a': 1}>

This can indeed be a pitfall. The trouble is, once you call d.a, that returns the value of the key a in dictionary d, which is an integer. You then just assign 5 to it. This is the same as:

a = 5

At that point the AttributesFrozenDict is no longer part of the process. It has no knowledge of the assignment, so it can also not raise. I don't see how we would solve this. We would have to override the __getattr__ of AttributesFrozenDict to always wrap the return variable in some custom class that would somehow raise when something is assigned to it. What method would be called in this case even? Anyway, I will transfer this to plumpy as really that is where the class comes from, but I don't have a solution.