Required field in Schema annotation ignored in Kotlin. Fixes #2021.

springdoc-openapi-kotlin/src/main/java/org/springdoc/kotlin/SpringDocKotlinConfiguration.kt

@@ -40,6 +40,7 @@ class SpringDocKotlinConfiguration(objectMapperProvider: ObjectMapperProvider) {
 			.addRequestWrapperToIgnore(Continuation::class.java)
 			.replaceWithSchema(ByteArray::class.java, ByteArraySchema())
 			.addDeprecatedType(Deprecated::class.java)
+		objectMapperProvider.jsonMapper().registerModule(SpringDocRequiredModule())
 		objectMapperProvider.jsonMapper().registerModule(KotlinModule.Builder().build())
 	}
 

springdoc-openapi-kotlin/src/main/java/org/springdoc/kotlin/SpringDocRequiredModule.java

@@ -0,0 +1,52 @@
+/*
+ *
+ *  *
+ *  *  *
+ *  *  *  * Copyright 2019-2022 the original author or authors.
+ *  *  *  *
+ *  *  *  * Licensed under the Apache License, Version 2.0 (the "License");
+ *  *  *  * you may not use this file except in compliance with the License.
+ *  *  *  * You may obtain a copy of the License at
+ *  *  *  *
+ *  *  *  *      https://www.apache.org/licenses/LICENSE-2.0
+ *  *  *  *
+ *  *  *  * Unless required by applicable law or agreed to in writing, software
+ *  *  *  * distributed under the License is distributed on an "AS IS" BASIS,
+ *  *  *  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  *  *  * See the License for the specific language governing permissions and
+ *  *  *  * limitations under the License.
+ *  *  *
+ *  *
+ *
+ */
+
+package org.springdoc.kotlin;
+
+import com.fasterxml.jackson.databind.introspect.AnnotatedMember;
+import com.fasterxml.jackson.databind.introspect.NopAnnotationIntrospector;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+import io.swagger.v3.oas.annotations.media.Schema;
+
+/**
+ * The type Spring doc required module.
+ *
+ * @author bnasslahsen
+ */
+public class SpringDocRequiredModule  extends SimpleModule {
+
+	@Override
+	public void setupModule(SetupContext context) {
+		context.insertAnnotationIntrospector(new RespectSchemaRequiredAnnotationIntrospector());
+	}
+
+	/**
+	 * The type Respect schema required annotation introspector.
+	 */
+	private static class RespectSchemaRequiredAnnotationIntrospector extends NopAnnotationIntrospector {
+		@Override
+		public Boolean hasRequiredMarker(AnnotatedMember m) {
+			Schema schemaAnnotation = m.getAnnotation(Schema.class);
+			return schemaAnnotation != null ? schemaAnnotation.required() : null;
+		}
+	}
+}

springdoc-openapi-kotlin/src/test/kotlin/test/org/springdoc/api/app9/DemoController.kt

@@ -0,0 +1,23 @@
+package test.org.springdoc.api.app9
+
+import io.swagger.v3.oas.annotations.media.Schema
+import org.springframework.web.bind.annotation.*
+
+@RestController
+@RequestMapping("/api/demo")
+class DocumentsApiController {
+
+    @GetMapping
+    suspend fun getDocuments( request: DemoRequest
+    ): DemoDto = DemoDto(42)
+}
+
+data class DemoDto(
+    var id: Long,
+)
+
+class DemoRequest {
+	@field:Schema(required = false, description = "Should not be required")
+	val nonNullableWithDefault: String = "a default value"
+
+}

springdoc-openapi-kotlin/src/test/kotlin/test/org/springdoc/api/app9/SpringDocApp9Test.kt

@@ -0,0 +1,31 @@
+/*
+ *
+ *  * Copyright 2019-2023 the original author or authors.
+ *  *
+ *  * Licensed under the Apache License, Version 2.0 (the "License");
+ *  * you may not use this file except in compliance with the License.
+ *  * You may obtain a copy of the License at
+ *  *
+ *  *      https://www.apache.org/licenses/LICENSE-2.0
+ *  *
+ *  * Unless required by applicable law or agreed to in writing, software
+ *  * distributed under the License is distributed on an "AS IS" BASIS,
+ *  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  * See the License for the specific language governing permissions and
+ *  * limitations under the License.
+ *
+ */
+
+package test.org.springdoc.api.app9
+
+import org.springframework.boot.autoconfigure.SpringBootApplication
+import org.springframework.context.annotation.ComponentScan
+import test.org.springdoc.api.AbstractKotlinSpringDocTest
+
+class SpringDocApp9Test : AbstractKotlinSpringDocTest() {
+
+	@SpringBootApplication
+	@ComponentScan(basePackages = ["org.springdoc", "test.org.springdoc.api.app9"])
+	open class DemoApplication
+
+}

springdoc-openapi-kotlin/src/test/resources/results/app9.json

@@ -0,0 +1,73 @@
+{
+  "openapi": "3.0.1",
+  "info": {
+    "title": "OpenAPI definition",
+    "version": "v0"
+  },
+  "servers": [
+    {
+      "url": "",
+      "description": "Generated server url"
+    }
+  ],
+  "paths": {
+    "/api/demo": {
+      "get": {
+        "tags": [
+          "documents-api-controller"
+        ],
+        "operationId": "getDocuments",
+        "parameters": [
+          {
+            "name": "request",
+            "in": "query",
+            "required": true,
+            "schema": {
+              "$ref": "#/components/schemas/DemoRequest"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "*/*": {
+                "schema": {
+                  "$ref": "#/components/schemas/DemoDto"
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  },
+  "components": {
+    "schemas": {
+      "DemoRequest": {
+        "required": [
+          "nonNullableWithDefault"
+        ],
+        "type": "object",
+        "properties": {
+          "nonNullableWithDefault": {
+            "type": "string",
+            "description": "Should not be required"
+          }
+        }
+      },
+      "DemoDto": {
+        "required": [
+          "id"
+        ],
+        "type": "object",
+        "properties": {
+          "id": {
+            "type": "integer",
+            "format": "int64"
+          }
+        }
+      }
+    }
+  }
+}