Merge pull request #188 from tonyandrewmeyer/fix-3.8-inspect-compat

fix: adjust the inspect.signature behaviour to work with Python 3.8

pyproject.toml

@@ -8,7 +8,7 @@ build-backend = "setuptools.build_meta"
 [project]
 name = "ops-scenario"
 
-version = "7.0.0"
+version = "7.0.1"
 
 authors = [
  { name = "Pietro Pasotti", email = "[email protected]" }

scenario/state.py

@@ -139,12 +139,13 @@ def __new__(cls, *args, **kwargs):
  # declared, which aligns with dataclasses. Simpler ways of
  # getting the arguments (like __annotations__) do not have that
  # guarantee, although in practice it is the case.
- parameters = inspect.signature(cls).parameters
+ parameters = inspect.signature(cls.__init__).parameters
  required_args = [
  name
  for name in tuple(parameters)
  if parameters[name].default is inspect.Parameter.empty
  and name not in kwargs
+ and name != "self"
  ]
  n_posargs = len(args)
  max_n_posargs = cls._max_positional_args