cfn-cli codegen oneOf union types is not handled

[dchakrav-github]

Updated Issue Description

The issue here is that we initially disallowed having a property be declared as multiple types. For example {"type": ["string", "array"]} was deemed to be invalid. This includes use of combiners (oneOf, anyOf, allOf) to declare multiple types as well.

We then loosened that restriction on the type property in #454, but we did not move the restriction for $ref, causing an inconsistency there

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Original Issue Description

When modeling AWS::SQS::Queue, we either have a FIFOQueue or StandardQueue for the type. This can be modeled via oneOf these 2 types. The property sets and property based constraints are different in these 2 sets. E.g. QueueName for FIFOQueue has to end with .fifo$ vs standard one doesn't have this constraint. oneOf semantics of JSONSchema is not handled.

aws-sqs-queue.json.txt

rpdk.core.jsonutils.utils.ConstraintError: Object at path '#' declared multiple values for '$ref': found '('definitions', 'StandardQueue')' and '('definitions', 'FifoQueue')'

rpdk.log

[tobywf]

Under the current resource schema, that schema is invalid:

$ cfn-cli validate
Resource specification is invalid: 'properties' is a required property
[...]

So we can't tackle this at the moment. Schema modifications should go through review on https://github.com/aws-cloudformation/aws-cloudformation-resource-schema first, and then we'll update the schema here as required.

[dchakrav-github]

Simplified examples demonstrating incorrect interpretation and generation of types even when compliant with the schema by introducing a properties section.

aws-sqs-queue.json.success.txt

Here the generate succeeds. The generated file completely ignored the second type which should have been mapped Map<String, Object>

// This is a generated file. Modifications will be overwritten.
package com.aws.sqs.queue;

import com.fasterxml.jackson.annotation.JsonProperty;
import java.util.Map;
import java.util.List;
import java.util.Set;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class ResourceModel {
    @JsonProperty("firstOrSecondType")
    private FirstType firstOrSecondType;

}

[dchakrav-github]

Second example fails to generate classes, when there are 2 alternating types that are referenced. This prevents the use of oneOf with $ref to other types.

aws-sqs-queue.json.failed.txt

rpdk.log

[dchakrav-github]

Inlined properties using oneOf that don't conflict on properties succeed but generate a single class that has all the properties merged. It isn't clear now which set of properties to set for FirstType vs SecondType

aws-sqs-queue.json.inlined.pass.txt

// This is a generated file. Modifications will be overwritten.
package com.aws.sqs.queue;

import com.fasterxml.jackson.annotation.JsonProperty;
import java.util.Map;
import java.util.List;
import java.util.Set;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class FirstOrSecondType {
    @JsonProperty("first1")
    private String first1;

    @JsonProperty("first2")
    private String first2;

    @JsonProperty("second1")
    private Float second1;

}

[ammokhov]

tracking #333