Support polymorphic validation

[whitlockjc]

Originally reported here: apigee-127/swagger-tools#241

[matthewspivey]

Is this blocked by the ambiguities in the spec (OAI/OpenAPI-Specification#403)?

[whitlockjc]

Yes and no. I think in the linked swagger-tools issue I got a good enough feel for how to do this but it's just not been a high priority. I do plan on it being done by v1.0.0 which is my current effort.

[IvanGoncharov]

@whitlockjc Do you have any progress on this?
This issue blocks me, so I can help by submitting PR for it.
I will start to work on it tomorrow, do you have any suggestion or concerns?

[whitlockjc]

I'm up for any help I can get, I've punted on this long enough. I've thought about this a few times but I have to tell you that this likely won't be easy. I've thought about it a few times but not recently. Let me give this some thought and I'll get back to you.

[IvanGoncharov]

I experience UNUSED_DEFINITION warnings, so I will try to fix it.
My idea is to find all schemes under definitions which has discriminator in them.
And then remove from unused list all schemes which have allOf with discriminator's schemes.
@whitlockjc Do you see any potential problems with such approach?

[whitlockjc]

Wait...so you don't want to implement discriminator validation, you just want to stop indirectly used references (discriminator) from being marked as UNUSED_DEFINITION? That is welcome too but that is not what it would take to do this work. :) Do feel free to reference this issue in your PR and commit message but don't use Fixes because it will not fix this issue completely. Make sense?

[whitlockjc]

As I think about this, I realize that the easiest way to do this might be to leverage JSON Schema, like we do for non-body parameters.

[IvanGoncharov]

@whitlockjc Do you mean converting discriminator into oneOf?

[IvanGoncharov]

Wait...so you don't want to implement discriminator validation, you just want to stop indirectly used references (discriminator) from being marked as UNUSED_DEFINITION?

You closed #58 as duplicate of this and it referenced swagger-api/swagger-editor#765 which is exactly what I want to fix.

[whitlockjc]

Ah, maybe I assumed on #58. "Support Discriminator" is a duplicate of this, as this issue is about general support for discriminator. I'm just saying that there are multiple parts to this:

• Handling definitions that are indirectly referenced via discriminators (Your current case)
• Handling discriminators during the request/response validation

Did that clear things up? As for how we'll do it, my though of using discriminator via oneOf, that was one idea but I've not done the work to prove that's the right approach. I'm all ears.

[ahultgren]

Any progress on this? (I'm also only interested in the unused definition warning)

[whitlockjc]

I thought @IvanGoncharov had an incoming PR for that but maybe I was wrong. I'm working on json-refs stuff now with hopes of releasing a new sway version within the next few days. At that time, I'll revisit this if Ivan hasn't.