Discover hooks via inspect.getattr_static

[RonnyPfannschmidt]

Written with AI assistance (Cursor, then Claude Code). I reviewed it and I am posting it.

Plugin registration used getattr() to find hookimpls, which executes every property and descriptor on the object just to look for markers. That is a side effect nobody asked for, and it falls over on objects whose attribute access raises.

This switches discovery to inspect.getattr_static(). Only plain functions, classmethod, staticmethod and bound methods are considered hookable; properties, cached_property and other descriptors are skipped without being evaluated.

Binding semantics

Discovery reproduces what getattr() would have returned, rather than replacing it:

• a function found on the class or module is returned unbound, as before;
• a function found on the instance — in its __dict__ or in a __slots__ slot — is also returned unbound, because getattr() does not run the descriptor protocol on instance storage. A hookimpl assigned in __init__ keeps its declared signature and gets no implicit self;
• classmethod/staticmethod are bound via __get__ after the scan instead of during it.

Thanks to @copilot for catching the instance-__dict__ case in review; the __slots__ variant, which silently dropped the hook altogether, turned up while fixing it. Both are covered by tests now.

Marker placement

One thing falls out of the static lookup: @hookimpl applied above @classmethod/@staticmethod now works. The marker sits on the wrapper, which the old getattr() path never saw, so those hooks were silently missed when registering an instance.

Notes

Supersedes #536, which addressed the property case by special-casing AttributeError. This branch is rebased on main and stands on its own — #536 can be closed once this lands.

src/pluggy/_manager.py is at 100% statement and branch coverage with these tests. pytest's own test suite passes unchanged against this branch (4554 passed).

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR refines Pluggy’s plugin hook discovery during PluginManager.register() and hookspec parsing by switching to inspect.getattr_static-based lookup to avoid triggering descriptors (e.g., @property, cached_property) while discovering @hookimpl/@hookspec markers. It also improves support for marker placement with @hookimpl stacked above @classmethod/@staticmethod, and binds callables via __get__ instead of using getattr() during discovery.

Changes:

• Add static (descriptor-safe) hook discovery helpers in PluginManager to skip properties/other descriptors without executing them.
• Discover @hookimpl markers when applied above @classmethod/@staticmethod wrappers.
• Add targeted regression tests ensuring registration does not evaluate properties/cached properties/raising descriptors and supports the new decorator ordering cases.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/pluggy/_manager.py	Implements inspect.getattr_static-based marker discovery and callable binding to avoid executing descriptors during registration/spec parsing.
testing/test_pluginmanager.py	Adds tests covering descriptor-safety during registration and hookimpl discovery for @hookimpl above @classmethod/@staticmethod.

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