Proposed fix for issue #358

[eachimei]

Switch to inspect.signature instead of inspect.getfullargspec to properly support wrapper chains (decorated functions) - see details in issue #358 .

In the proposed change I tried to do the minimal required changes to varnames.

[RonnyPfannschmidt]

Lovely start, please see my comments for the self handling

[RonnyPfannschmidt]

If a method signature conveniently skips self, then we could drop the pypy vs cython drop self hack just below by always using func here

[eachimei]

I thought about that, and the challenge/problem then becomes with cases where @hookspec is used on methods or when a class object is passed into varnames (then the class __init__ is used). Meaning, in those cases func is an unbound function so signature(func) doesn't skip self. However, in the existing ("old") implementation, self is always stripped (even when func is unbound).

[RonnyPfannschmidt]

those are cases we might want to deprecate in a followup

1. while signatures of Myclass.__init__ include self, signatures of a Myclass do work correct
2. its arguably a mistake that hookspecs as classes where allowed, we should have passed in a object in any case

i'll open up issues for that

[RonnyPfannschmidt]

looks good, thanks

the failures seem unrelated, will fix them later today + merge this

[eachimei]

That's great, thank you 😊

[nicoddemus]

@eachimei can you please rebase this over main? It should run cleanly now.

[eachimei]

@eachimei can you please rebase this over main? It should run cleanly now.
@nicoddemus , I rebased so we have fresh results now

[nicoddemus]

Thanks @eachimei!

@RonnyPfannschmidt is this good to merge now?

[RonnyPfannschmidt]

It seems like we didn't install pre-commit here as well, the lint fail is from that, so lint fix needed

[nicoddemus]

Enabled pre-commit for pluggy. 👍

[nicoddemus]

I did fix it locally but unfortunately I cannot push to eachimei:main (permission denied), here's the diff:

diff --git a/src/pluggy/_hooks.py b/src/pluggy/_hooks.py
index d376eca..73f0e80 100644
--- a/src/pluggy/_hooks.py
+++ b/src/pluggy/_hooks.py
@@ -244,8 +244,11 @@ def varnames(func: object) -> Tuple[Tuple[str, ...], Tuple[str, ...]]:
         except Exception:
             return (), ()

-    try:  # func MUST be a function or method here or we won't parse any args
-        sig = inspect.signature(func.__func__ if inspect.ismethod(func) else func)
+    try:
+        # func MUST be a function or method here or we won't parse any args.
+        sig = inspect.signature(
+            func.__func__ if inspect.ismethod(func) else func  # type:ignore[arg-type]
+        )
     except TypeError:
         return (), ()

diff --git a/testing/test_helpers.py b/testing/test_helpers.py
index d7ec6ce..4ddd945 100644
--- a/testing/test_helpers.py
+++ b/testing/test_helpers.py
@@ -87,12 +87,13 @@ def test_formatdef() -> None:


 def test_varnames_decorator() -> None:
-    F = TypeVar('F', bound=Callable[..., Any])
+    F = TypeVar("F", bound=Callable[..., Any])

     def my_decorator(func: F) -> F:
         @wraps(func)
         def wrapper(*args, **kwargs):
             return func(*args, **kwargs)
+
         return cast(F, wrapper)

     @my_decorator

[eachimei]

@nicoddemus can you please retry? It had the "allow edit" setting set to "false", it should work now

[nicoddemus]

Yeah now it works. 👍