fix(openapi): improves schema type detection when generating examples.

mock/openapi/src/main/java/io/gatehill/imposter/plugin/openapi/service/SchemaServiceImpl.kt

@@ -118,7 +118,7 @@ class SchemaServiceImpl : SchemaService {
  is ObjectSchema -> buildFromProperties(spec, schema.properties)
  is ArraySchema -> buildFromArraySchema(spec, schema)
  is ComposedSchema -> buildFromComposedSchema(spec, schema)
- else -> getPropertyDefault(schema, propNameHint)
+ else -> determineFromType(spec, schema, propNameHint)
  }
  }
  return example
@@ -127,7 +127,51 @@ class SchemaServiceImpl : SchemaService {
  }
  }
 
- private fun buildFromArraySchema(spec: OpenAPI, schema: ArraySchema): List<Any?> {
+ /**
+ * Use the schema `type` or `types` (OpenAPI 3.1) properties to build an example.
+ */
+ private fun determineFromType(spec: OpenAPI, schema: Schema<*>, propNameHint: String?): Any? {
+ schema.type?.let { schemaType ->
+ return buildFromType(spec, schema, schemaType, propNameHint)
+
+ } ?: schema.types?.let { schemaTypes ->
+ if (schemaTypes.isEmpty()) {
+ LOGGER.warn("Schema type is null and no schema types set [propName={}] - falling back to property default: {}", propNameHint, schema)
+ return getPropertyDefault(schema, propNameHint)
+ } else {
+ val schemaType = schemaTypes.first()
+ if (schemaTypes.size > 1) {
+ // TODO consider `null` as a valid type in an array of `types` in OpenAPI 3.1 - choose first non-null
+ LOGGER.warn("More than one schema type ({}) set [propName={}] - choosing first: {}", schemaTypes, propNameHint, schemaType)
+ } else {
+ LOGGER.trace("Exactly one schema type set [propName={}]: {}", propNameHint, schemaType)
+ }
+ return buildFromType(spec, schema, schemaType, propNameHint)
+ }
+ } ?: run {
+ LOGGER.warn("No schema type or types set - falling back to property default for '{}', {}", propNameHint, schema)
+ return getPropertyDefault(schema, propNameHint)
+ }
+ }
+
+ /**
+ * Use the given schema type to build an example.
+ */
+ private fun buildFromType(
+ spec: OpenAPI,
+ schema: Schema<*>,
+ schemaType: String,
+ propNameHint: String?,
+ ) = when (schemaType) {
+ "array" -> buildFromArraySchema(spec, schema)
+ "object" -> buildFromProperties(spec, schema.properties)
+ else -> {
+ // schema type is not an aggregate - look for specific example
+ getPropertyDefault(schema, propNameHint)
+ }
+ }
+
+ private fun buildFromArraySchema(spec: OpenAPI, schema: Schema<*>): List<Any?> {
  if (null == schema.items) {
  return emptyList()
  }