Request parameters with default values are marked as required. Fixes #2149

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

@@ -16,13 +16,16 @@ import org.springframework.context.annotation.Configuration
 import org.springframework.context.annotation.Lazy
 import org.springframework.core.MethodParameter
 import org.springframework.core.annotation.AnnotatedElementUtils
+import org.springframework.web.bind.annotation.RequestParam
+import org.springframework.web.bind.annotation.ValueConstants
 import kotlin.coroutines.Continuation
 import kotlin.reflect.KParameter
 import kotlin.reflect.jvm.kotlinFunction
 
 /**
  * The type Spring doc kotlin configuration.
  * @author bnasslahsen
+ * @author tobiberger
  */
 @Lazy(false)
 @Configuration(proxyBeanMethods = false)
@@ -77,9 +80,16 @@ class SpringDocKotlinConfiguration(objectMapperProvider: ObjectMapperProvider) {
 					AnnotatedElementUtils.forAnnotations(*methodParameter.parameterAnnotations),
 					Parameter::class.java
 				)
+				val requestParam = AnnotatedElementUtils.findMergedAnnotation(
+						AnnotatedElementUtils.forAnnotations(*methodParameter.parameterAnnotations),
+						RequestParam::class.java
+				)
 				// Swagger @Parameter annotation takes precedence
 				if (parameterDoc != null && parameterDoc.required)
 					parameterModel.required = parameterDoc.required
+				// parameter is not required if a default value is provided in @RequestParam
+				else if (requestParam != null && requestParam.defaultValue != ValueConstants.DEFAULT_NONE)
+					parameterModel.required = false
 				else
 					parameterModel.required = kParameter.type.isMarkedNullable == false
 			}

springdoc-openapi-kotlin/src/test/kotlin/test/org/springdoc/api/app10/ExampleController.kt

@@ -0,0 +1,20 @@
+package test.org.springdoc.api.app10
+
+import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.web.bind.annotation.RequestParam
+import org.springframework.web.bind.annotation.RestController
+import test.org.springdoc.api.app8.Greeting
+
+data class Greeting(val greeting: String)
+
+@RestController
+class ExampleController {
+	@GetMapping("/")
+	fun greet(@RequestParam name: String?) = Greeting("Hello ${name ?: "world"}")
+
+	@GetMapping("/test")
+	fun test(@RequestParam name: String) = Greeting("Hello $name")
+
+	@GetMapping("/test-with-default")
+	fun testWithDefault(@RequestParam(defaultValue = "world") name: String) = Greeting("Hello $name")
+}

springdoc-openapi-kotlin/src/test/kotlin/test/org/springdoc/api/app10/SpringDocApp10Test.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.app10
+
+import org.springframework.boot.autoconfigure.SpringBootApplication
+import org.springframework.context.annotation.ComponentScan
+import test.org.springdoc.api.AbstractKotlinSpringDocTest
+
+class SpringDocApp10Test : AbstractKotlinSpringDocTest() {
+
+	@SpringBootApplication
+	@ComponentScan(basePackages = ["org.springdoc", "test.org.springdoc.api.app10"])
+	open class DemoApplication
+
+}

springdoc-openapi-kotlin/src/test/resources/results/app10.json

@@ -0,0 +1,121 @@
+{
+  "openapi": "3.0.1",
+  "info": {
+    "title": "OpenAPI definition",
+    "version": "v0"
+  },
+  "servers": [
+    {
+      "url": "",
+      "description": "Generated server url"
+    }
+  ],
+  "paths": {
+    "/": {
+      "get": {
+        "tags": [
+          "example-controller"
+        ],
+        "operationId": "greet",
+        "parameters": [
+          {
+            "name": "name",
+            "in": "query",
+            "required": false,
+            "schema": {
+              "type": "string"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "*/*": {
+                "schema": {
+                  "$ref": "#/components/schemas/Greeting"
+                }
+              }
+            }
+          }
+        }
+      }
+    },
+    "/test": {
+      "get": {
+        "tags": [
+          "example-controller"
+        ],
+        "operationId": "test",
+        "parameters": [
+          {
+            "name": "name",
+            "in": "query",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "*/*": {
+                "schema": {
+                  "$ref": "#/components/schemas/Greeting"
+                }
+              }
+            }
+          }
+        }
+      }
+    },
+    "/test-with-default": {
+      "get": {
+        "tags": [
+          "example-controller"
+        ],
+        "operationId": "testWithDefault",
+        "parameters": [
+          {
+            "name": "name",
+            "in": "query",
+            "required": false,
+            "schema": {
+              "type": "string",
+              "default": "world"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "*/*": {
+                "schema": {
+                  "$ref": "#/components/schemas/Greeting"
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  },
+  "components": {
+    "schemas": {
+      "Greeting": {
+        "required": [
+          "greeting"
+        ],
+        "type": "object",
+        "properties": {
+          "greeting": {
+            "type": "string"
+          }
+        }
+      }
+    }
+  }
+}