Guideline for using `static_fields`?

Hi,

Most of the nn.Modules (MLP) use static_fields for, well seemingly static attributes. In the documentation it is stated that static_field should be used rarely. Is there a do’s and don’ts for their usage? As I understand these can be filtered out with *filter calls.

Thanks.

[patrick-kidger]

Don’t worry, it definitely isn’t going away. If nothing else it’s a key part of how things work internally.

On balance I think I’m inclined to maintain the status quo. This clearly does break a couple of tests, and whilst they’re pretty minor it’s not encouraging. To rebut the argument (my argument) in favour of not using static_field: if an end-user overzealously applies a static_field then I don’t think it should actually matter – you can’t smuggle in JAX arrays this way as they’re not hashable. So extra static_fields should never break you silently.

[paganpasta]

The more I am interacting with equinox <=> jax/optax I am thinking having static_fields() is not that bad to have as default. Saves the trouble of repeating filtering at places.