Conflict of types

[samwaseda]

pyiron_snippets/pyiron_snippets/resources.py

Lines 124 to 126 in 1fe7e8b

	if resolvers == ():
	return self
	return ResolverChain(self, *resolvers)

These lines smell, not only because mypy told me that there's a type conflict, but also because it appears quite inconsistent that AbstractResolver returns ResolverChain. Could you explain the rationale? @liamhuber

[liamhuber]

@pmrv?

[pmrv]

mypy complains

pyiron_snippets/resources.py:128: error: Incompatible return value type (got "AbstractResolver", expected "ResolverChain")  [return-value]

because it can also return the type itself, so the annotation is incomplete. I fixed the issues in #53.

I don't see a more general inconsistency with this setup, though. chain is a generic method, but returns a concrete type. This is quite common, e.g., type(itertools.chain(...)) is always itertools.chain and type(sorted(...)) is always list, no matter the type of the input iterables.