parameterized.expand uses slow inspect.stack

[gatesn]

Almost half of my pytest collection time is spent inside parameterized.expand, specifically inside inspect.stack. I tried switching to inspect.currentframe and it's significantly faster as it doesn't have to assemble the entire stack just to look at the outer frame.

i.e.

parameterized/parameterized/parameterized.py

Lines 493 to 495 in ff5a1da

	stack = inspect.stack()
	frame = stack[1]
	frame_locals = frame[0].f_locals

to

frame_locals = inspect.currentframe().f_back.f_locals

[wolever]

Hey! Thanks!

0.7.5 will fix the issue you called out. There's still one more use that may affect things:

    def _terrible_magic_get_defining_classes(self):
        """ Returns the set of parent classes of the class currently being defined.
            Will likely only work if called from the ``parameterized`` decorator.
            This function is entirely @brandon_rhodes's fault, as he suggested
            the implementation: http://stackoverflow.com/a/8793684/71522
            """
        stack = inspect.stack()
        if len(stack) <= 4:
            return []
        frame = stack[4]
        code_context = frame[4] and frame[4][0].strip()
        if not (code_context and code_context.startswith("class ")):
            return []
        _, _, parents = code_context.partition("(")
        parents, _, _ = parents.partition(")")
        return eval("[" + parents + "]", frame[0].f_globals, frame[0].f_locals)

But this will take a bit more work + testing to fix, so I'm going to hold off until I have the time (and, ofc, I'd love a PR)