OpenAPITools / OpenAPITools/openapi-generator
[BUG] [kotlin-spring] MissingKotlinParameterException instead of BeanValidation exception for missing required property
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Description
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?
- [Optional] Bounty to sponsor the fix (example)
Description
I defined a required property but instead of getting a bean validation exception, I get a MissingKotlinParameterException:
com.fasterxml.jackson.module.kotlin.MissingKotlinParameterException: Instantiation of [simple type, class dto.Component] value failed for JSON property type due to missing (therefore NULL) value for creator parameter type which is a non-nullable type
at [Source: (PushbackInputStream); line: 1, column: 2] (through reference chain: dto.Component["type"])
Here is the generated DTO:
data class Component (
@get:NotNull
@ApiModelProperty(required = true, value = "")
@JsonProperty("type") val type: kotlin.String,
@ApiModelProperty(value = "")
@JsonProperty("model") val model: kotlin.String? = null
)
It seems validation is done after the dto is instantiated... and as a required field is null, it can't create a new instance of this dto.
openapi-generator version
kotlin-spring with 4.2.2
OpenAPI declaration file content or url
Component:
type: object
required:
- type
properties:
type:
type: string
model:
type: string
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the issue with the provided Component schema and generated kotlin-spring DTO, focusing on the interaction between Jackson construction and bean validation. Compare the MissingKotlinParameterException with the expected Bean Validation failure; done means a missing required type is reported through bean validation instead of preventing DTO instantiation.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- kotlin, openapi, spring
- Domain
- api, backend, testing
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100