[bug][Kotlin] Default typeMapping for 'date' should be LocalDate

[legzo]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?

Description

When a spec specifies a property as :

"type": "string",
"format": "date",

the Kotlin generator generates the corresponding field as a LocalDateTime and later, the parsing fails when Jackson is used (Gson too) saying it cannot find a converter for this type.

As I understand the spec, "format":"date" should result in a LocalDate and "format":"date-time" in a LocalDateTime

openapi-generator version

I tried version 3.3.4, but I read the code of master and the problem is still present.

Steps to reproduce

Use as an input any spec that has a property configured as :

"type": "string",
"format": "date",

Suggest a fix/enhancement

I think there is only one line to change at

openapi-generator/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractKotlinCodegen.java

Line 175 in 0b66fa5

typeMapping.put("Date", "java.time.LocalDateTime");

it should be

 typeMapping.put("Date", "java.time.LocalDate");

I can provide a PR if you think it is really a bug.

Cheers.

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[legzo]

@jimschubert , @dr4ke616 : what's your take on that ?

[jimschubert]

@legzo I do think this would be considered a bug. There's always a workaround with type mappings in that you can specify them on the command line. Some generators may set certain mappings in such a way that user overrides aren't supported (as with Kotlin client json types).

If you're able to open a PR, that would be awesome. I'm in a crunch at work and it's been taking away from my open source contrib time.

[jimschubert]

I've tagged this as client/server related, since this is in the base class. Will evaluate the full impact later.

[legzo]

Hi @jimschubert, thanks for your feedback.

As a matter of fact I overrid the mapping in the config of the generator, so there is a work around. However I find it deceptive that out of the box Jackson is not able to deserialize a model that is propertly typed and formatted in the json.

I'll make a PR and you'll decide what to do with it :)

Thank you for your open-source contrib by the way. Much appreciated.