[Go][Server] Optional Query Parameters Support - Option 2

[icubbon]

If query parameters are not required and don't have a default, make them a pointer so that the server code can determine if they were provided or omitted.

A design decision was made to treat query params that were declared but not provided a value to be nil. e.g. GET api/foo?bar= would result in the bar variable being nil if it were not required, didn't have a default value, and was a numeric type.

This is a different option to #16980

I did not create a go-server-deprecated implementation for this PR. I want to wait before doing that work if this option is preferred.

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@lwj5 @wing328

[lwj5]

This is out of spec, you may want to create your own fork if you require such a design. api/foo?bar= does not mean nil, it means "".

Here's a good answer for the meaning in openapi https://stackoverflow.com/questions/45575493/what-does-required-in-openapi-really-mean

Query params follow similar logic.

[lwj5]

With regard to the empty value, I've found the following resources:

OAI/OpenAPI-Specification#1573
OAI/OpenAPI-Specification#3217

if you need to use empty values for your param, you can follow the case in OAI/OpenAPI-Specification#3217. However, the current go-server generator does not deal with polymorphism.