Support case-insensitive OData system query parameters

[Ndiritu]

OData 4.01 services support case-insensitive query parameters (without the $ prefix) e.g. filter, expand etc - https://learn.microsoft.com/en-us/odata/concepts/queryoptions-overview#system-query-options

This should be reflected in the OpenAPI descriptions.

Here's an SDK customer scenario impacted by this.

[andrueastman]

In my head this may actually be a service/workload issue.
$filter should be functionally equivalent to filter in odata 4.0 so using either shouldn't have different behavior. Specifying both in the openApi description would lead to larger openApi description and larger SDKs generated.

[Ndiritu]

Oh I see. Thanks @andrueastman. I skimmed through the docs a bit too fast.
Closing this.