feat: Change optional Open API query parameters to allow None BNCH-20153

[forest-benchling]

Fixes openapi-generators#285.

Instead of methods like

def sync_detailed(
    *,
    client: Client,
    size: Union[Unset, int] = UNSET,
) -> Response[Thing]:

we will now generate

def sync_detailed(
    *,
    client: Client,
    size: Union[Unset, None, int] = None,
) -> Response[Thing]:

and treat None the same as Unset.

This is a bit different from the original proposal in the issue, but if you scroll down you can see that it's what was agreed upon in the end IIUC (though I wasn't sure if we agreed on what the default value should be). In addition, it has the benefit of preserving back-compat.

I will submit a PR upstream, but first wanted to get early feedback internally.

[bowenwr]

Awesome work, I pulled this in to the client and ran the SDK tests against it. Fixed the functional issues and appeased MyPy. Let's get this open upstream! Thank you!

[packyg]

LGTM. Can't say I love the proliferation of args to functions and templates, but doesn't seem to be a way around it.

Approving but agree upstreaming would be the ideal way to incorporate this

[packyg]

Would it make more sense to label this flag more to what it does than how it's used along the lines of

Suggested change

	def get_type_string(self, no_optional: bool = False, query_parameter: bool = False) -> str:
	def get_type_string(self, no_optional: bool = False, treat_none_as_unset: bool = False) -> str:

(I don't think I really like treat_none_as_unset, but you get my point)

[forest-benchling]

Hmm, interesting idea. I could see that being useful in a future world where treat_none_as_unset might be used in different situations. Since for now we only have one use case, which is query parameters, I think it's more descriptive to keep it as is (especially if we end up changing the behavior of query parameters again).