StackOverflowError with Kotlin Sealed Class Hierarchy and @JsonSubTypes after upgrading to 2.8.5

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We are experiencing a StackOverflowError during OpenAPI schema generation after upgrading springdoc-openapi-starter-common and springdoc-openapi-starter-webmvc-ui from version 2.3.0 to 2.8.5. This upgrade was part of a larger update, including Spring Boot from 3.3.7 to 3.4.1. We are using Kotlin and Gradle.

The issue appears to be related to the processing of a sealed class hierarchy with @JsonSubTypes annotation. The structure is similar to the following:

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "@type")
@JsonSubTypes(
    JsonSubTypes.Type(value = ConcreteClassA::class, nams = "TYPE_A"),
    JsonSubTypes.Type(value = ConcreteClassB::class, name = "TYPE_B"),
    // ... more subtypes ...
    JsonSubTypes.Type(value = ConcreteClassWithGrandchild::class, name = "TYPE_WITH_GRANDCHILD"),
    // ... more subtypes ...

)
sealed class AbstractBaseClass {
    abstract fun someAbstractFunction(): String?

    open fun anotherFunction() = someAbstractFunction() ?: ""
}

// Example of a simple subclass
data class ConcreteClassA(
    val someProperty: String?
) : AbstractBaseClass() {
    override fun someAbstractFunction(): String? { /* implementation */ }
}

// Intermediate abstract class
sealed class IntermediateAbstractClass : AbstractBaseClass() {
    abstract val commonProperty1: String?
    abstract val commonProperty2: String?
}
// Example of class extends to another sealed class
data class ConcreteClassWithGrandchild(
    @JsonAlias("alias_prop1")
    @JsonInclude(JsonInclude.Include.NON_NULL)
    override val commonProperty1: String? = null,

    @JsonAlias("alias_prop2")
    @JsonInclude(JsonInclude.Include.NON_NULL)
    val specificProperty: String?,

     override val commonProperty2: String?,

) : IntermediateAbstractClass() {
    override fun someAbstractFunction() = "someValue"
}

The key points are:

• A sealed class (AbstractBaseClass) is used as the base.
• @JsonTypeInfo and @JsonSubTypes are used for polymorphic deserialization.
• There are multiple concrete subclasses, and, importantly, at least one subclass (ConcreteClassWithGrandchild) extends to another sealed class (IntermediateAbstractClass).
• Some properties use @JsonAlias and @JsonInclude.

The exception occurs during the openApiGenerate Gradle task. The stack trace indicates a stack overflow within org.openapitools.codegen.DefaultCodegen.getAllOfDescendants, suggesting a problem with recursive processing of the class hierarchy.

org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':openApiGenerate'.
  ...
Caused by: org.gradle.api.GradleException: Code generation failed.
  ...
Caused by: java.lang.RuntimeException: Could not process model 'AbstractBaseClass'.Please make sure that your schema is correct!
  ...
Caused by: java.lang.RuntimeException: Stack overflow hit when looking for AbstractBaseClass an infinite loop starting and ending at ConcreteClassWithGrandchild was seen
    at org.openapitools.codegen.DefaultCodegen.getAllOfDescendants(DefaultCodegen.java:3491)
    at org.openapitools.codegen.DefaultCodegen.createDiscriminator(DefaultCodegen.java:3573)
    at org.openapitools.codegen.DefaultCodegen.fromModel(DefaultCodegen.java:3035)
    at org.openapitools.codegen.DefaultGenerator.processModels(DefaultGenerator.java:1765)
    at org.openapitools.codegen.DefaultGenerator.generateModels(DefaultGenerator.java:523)
  ...

This issue seems related to the previously reported and fixed issue: #2603. However, that fix doesn't seem to resolve the problem in our case, potentially because of the grandchild sealed class relationship, or some interaction with the other annotations.

Expected Behavior:
The OpenAPI schema should be generated successfully without a StackOverflowError.

Actual Behavior:
A StackOverflowError occurs during schema generation, preventing the build from completing.

Steps to Reproduce:
While I can't share the exact code, the provided class structure above outlines a simplified version. Creating a similar setup with:

• Kotlin sealed class.
• Multiple subtypes.
• Grandchild in sealed class hierarchy.
• @JsonTypeInfo, @JsonSubTypes, @JsonAlias, and @JsonInclude annotations.
• Spring Boot 3.4.1 and springdoc-openapi 2.8.5

should reproduce it.

Environment:

• Spring Boot: 3.4.1
• springdoc-openapi-starter-common: 2.8.5
• springdoc-openapi-starter-webmvc-ui: 2.8.5
• Kotlin
• Gradle

Could you please investigate this issue? It's breaking our doc generation completely. Thank you!