[kotlin][client] Explode query param properly

[maksim-kosolapov]

Problem

It's not possible to use request objects in the API (e.g. findItems(SearchRequest(name, status, fromDate, ...))). One more example is a pagination parameter, something like Page(size,offset). I'd like to use a model in the API but it's not possible at the moment.

Kotlin Client generator is not exploding a query object properly. It uses the object toString() method, so API request doesn't work. See OpenAPI Parameter Serialization.

Used isModel, isDeepObject, vars template variables to fill localVariableQuery with the fields of the query object.

It should work fine for objects with primitive, enum, date props. The behavior for nested objects and arrays is undefined (And it is mentioned in the doc)

The generated QueryApi.kt sample from the echo-api shows the expected query parameters.

To close #20715

CC: @dr4ke616 @karismann @Zomzog @andrewemery @4brunu @yutaka0m @stefankoppier @e5l

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[maksim-kosolapov]

@dr4ke616 @karismann @Zomzog @andrewemery @4brunu @yutaka0m @stefankoppier @e5l or anybody, hey folks! could you explain what does this message mean? I'm curious if it's a blocker for review

[wing328]

thanks for the PR, which has been merged

[maksim-kosolapov]

thanks for the PR, which has been merged

Thanks for looking into it.

qq: does the above "Merging is blocked" just say me that I have no permissions to merge? The message is unclear then, it looks like there are some settings in the repo blocking merge)

[wing328]

i would think so

(i don't see this message in my side as i've the merge right)