Description

This PR replaces use of lazy_object_proxy.slots.Proxy with a new custom slots-based Proxy implementation. Compared to the prior Proxy implementation with extended lazy_object_proxy.slots.Proxy to add different pickling mechanics, the new proxystore.proxy.Proxy has better handling for __module__ access, a simpler MRO hierarchy (i.e., less inheritance), correct support for __annotations__, and drops magic methods deprecated in Python 3.

Of these changes, the most important is that __module__ now behaves differently if accessed on Proxy directly or an instance of Proxy.

>>> from proxystore.proxy import Proxy
>>> Proxy.__module__
'proxystore.proxy'
>>> Proxy.__name__
'Proxy'
>>> proxy = Proxy(lambda: object)
>>> proxy.__module__
'builtins'
>>> proxy.__name__
'object'

This change addresses many long-standing headaches related to using proxies:

• help(proxystore.proxy) works correctly and no longer raises a vague TypeError: '<' not supported between instances of 'str' and 'property'.
• Serializers which inspect the __module__ attribute of object types no longer fail (as in Parsl and Dask).
• A trampoline function is no longer needed for pickle to correctly reconstruct the type.

Internally, this required a lot of changes. Most importantly is that lazy_object_proxy.slots.Proxy needed to be modified so that source has been copied into ProxyStore's source and modified. The license for lazy-object-proxy is now included in THIRD_PARTY_LICENSES and included in the relevant source files containing the third-party code.

Fixes

• Fixes Improve handling of attribute access on Proxy class #517

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 a lot of new tests.

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.