Swagger spec geneerated incorrectly if jackson-module-kotlin present

[dekar91]

Hi here!

If dependency jackson-module-kotlin](com.fasterxml.jackson.module:jackson-module-kotlin) present in gradle (without any additional configuration) all kotlin properties startling with one letter and a word Index duplicated in swagger yaml.

Example:

data class Result(
    val result: Int,
    val aIndex: Int,
    val someIndex: Int,
    val bIndex: Int
)

Generated as:

{
  "Result": {
    "required": [
      "aindex",
      "bindex",
      "result",
      "someIndex"
    ],
    "type": "object",
    "properties": {
      "result": {
        "type": "integer",
        "format": "int32"
      },
      "aIndex": {
        "type": "integer",
        "format": "int32",
        "writeOnly": true
      },
      "someIndex": {
        "type": "integer",
        "format": "int32"
      },
      "bIndex": {
        "type": "integer",
        "format": "int32",
        "writeOnly": true
      },
      "aindex": {
        "type": "integer",
        "format": "int32"
      },
      "bindex": {
        "type": "integer",
        "format": "int32"
      }
    }
  }
}

To Reproduce
Steps to reproduce the behavior:

gradle.kts:

plugins {
    id("org.springframework.boot") version "3.3.0"
    id("io.spring.dependency-management") version "1.1.5"
    kotlin("jvm") version "2.0.0"
    kotlin("plugin.spring") version "2.0.0"

}

group = "org.example"
version = "0.0.1-SNAPSHOT"

java {
    toolchain {
        languageVersion = JavaLanguageVersion.of(21)
    }
}

repositories {
    mavenCentral()
}

dependencies {
    implementation("org.springframework.boot:spring-boot-starter-webflux")
    annotationProcessor("org.springframework.boot:spring-boot-configuration-processor")

    implementation("org.springframework.boot:spring-boot-starter")
    implementation("org.springframework.boot:spring-boot-starter-webflux")
    implementation("org.springdoc:springdoc-openapi-starter-webflux-ui:2.5.0")
    implementation("org.springframework.boot:spring-boot-starter-webflux")
    implementation("com.fasterxml.jackson.module:jackson-module-kotlin") // If comment this line the bug disappears
}

kotlin {
    compilerOptions {
        freeCompilerArgs.addAll("-Xjsr305=strict")
    }
}

tasks.withType<Test> {
    useJUnitPlatform()
}

Controller:

@RestController
class Controller  {
    @GetMapping
     fun hello(): Result =  Result(
            result = 1,
            aIndex = 2,
            someIndex = 1,
            bIndex = 3,
        )

    data class Result(
        val result: Int,
        val aIndex: Int,
        val someIndex: Int,
        val bIndex: Int
    )
}

Expected behavior

Properties starting with ?Index not duplicated in lowercase.

Screenshots
UI:

Additional context
Archived app:
duplicatedproperties.zip

[bnasslahsen]

@dekar91,

This is a related to the following jackson-module-kotlin issue:FasterXML/jackson-module-kotlin#630

Here is the workaround:

    data class Result(
        val result: Int,
		@get:JsonProperty("aIndex")
		val aIndex: Int,
		val someIndex: Int,
		@get:JsonProperty("bIndex")
		val bIndex: Int
    )