Description

This PR adds the cache_defaults and target parameters to Proxy. When used together, the proxy caches default values of __class__ and __hash__ so that hash(proxy) and isinstance(proxy, ...) can be used without needing the resolve the proxy. The populate_target flag of Store methods now defaults to also setting cache_defaults=True.

Because this change added more special attributes to the Proxy class, I renamed all special attributes (__wrapped__, __factory__, __resolved__, etc.) to be prefixed by __proxy_* to better distinguish what is a property of Proxy versus the target. This is not considered a breaking change because those properties are an internal implementation detail of the Proxy class.

Fixes

• Fixes Support paths for hash and isinstance that does not resolve a Proxy #549

Type of Change

• Breaking Change (fix or enhancement which changes existing semantics of the public interface)
• Enhancement (new features or improvements to existing functionality)
• Bug (fixes for a bug or issue)
• Internal (refactoring, style changes, testing, optimizations)
• Documentation update (changes to documentation or examples)
• Package (dependencies, versions, package metadata)
• Development (CI workflows, pre-commit, linters, templates)
• Security (security related changes)

Testing

Added new unit tests for the features.

I also validated against this Dask example:

import logging
import tempfile

from dask.distributed import Client
from proxystore.connectors.file import FileConnector
from proxystore.store import Store

logging.basicConfig(level=logging.DEBUG)

if __name__ == '__main__':
    with tempfile.TemporaryDirectory() as tmp_dir:
        with Store('default', FileConnector(tmp_dir)) as store:
            client = Client(processes=True)

            x = list(range(100))
            p = store.proxy(x, populate_target=True)
            y = client.submit(sum, p)

            print(f'Result: {y.result()}')

            client.close()

Here, when populate_target=False, the proxy will be resolved three times: on the client when the proxy is serialized, on the scheduler when Dask does its input management, and on the worker when the proxy is actually used. With populate_target=True, the proxy is only resolved once on the worker when actually used.

Pull Request Checklist

• I have read the Contributing and PR submission guides.

Please confirm the PR meets the following requirements.

• Tags added to PR (e.g., breaking, bug, enhancement, internal, documentation, package, development, security).
• Code changes pass pre-commit (e.g., mypy, ruff, etc.).
• Tests have been added to show the fix is effective or that the new feature works.
• New and existing unit tests pass locally with the changes.
• Docs have been updated and reviewed if relevant.