BeanValidationFactory StackOverflowError with MappedCollectionDataTypePrimitive

[TheRealGuru]

BeanValidationFactory.validate() infinite recursion with MappedCollectionDataTypePrimitive

Description

(Yes this is almost idiot protection because I ran into this, but the stackoverflow error is extremely hard to diagnose once the mistake has been made).

When bean-validation: jakarta is enabled and a schema property uses format: byte (or format: binary) with a type mapping to byte[], code generation fails with a StackOverflowError.

Root Cause

MappedCollectionDataTypePrimitive implements CollectionDataType and its item property returns this:

override val item: DataType
get() = this
BeanValidationFactory.validate() checks dataType is CollectionDataType and recurses into validate(dataType.item). Since item points back to itself, this creates infinite recursion.

Steps to Reproduce

1. Create a schema with a string property using format: byte:
   MyRequest:
   type: object
   properties:
   payload:
   type: string
   format: byte
2. Add a type mapping: string:byte => byte[]
3. Enable bean-validation: jakarta
4. Run the processor

Expected Behaviour

Either:

• BeanValidationFactory.validate() detects the self-referential item and breaks the recursion (e.g. if (dataType.item === dataType) return), or
• A clear error message is produced explaining the incompatibility

Actual Behaviour

StackOverflowError with no indication of which schema or property caused it.

Version

openapi-processor-spring 2026.1

[hauner]

I can reproduce it...

[hauner]

Thanks for reporting :-)

you can use the fix by adding core 2026.2.1 to the plugin dependencies

with maven:

  <plugin>
      <groupId>io.openapiprocessor</groupId>
      <artifactId>openapi-processor-maven-plugin</artifactId>
      <version>${openapiprocessor.maven}</version>

      <dependencies>
          <dependency>
              <groupId>io.openapiprocessor</groupId>
              <artifactId>openapi-processor-spring</artifactId>
              <version>${openapiprocessor.spring}</version>
          </dependency>
          <dependency>
              <groupId>io.openapiprocessor</groupId>
              <artifactId>openapi-processor-core</artifactId>
             <version>2026.2.1</version>
          </dependency>

          <!-- ... -->

      <dependencies>

      <!-- ... -->

  </plugin>

or gradle:

openapiProcessor {
    // ...
    process("spring") {
        processor("${oap.processor.spring.get()}")
        processor("io.openapiprocessor:openapi-processor-core:2026.2.1")
        // ...
   }
   / ...
}