Support returning null in ParameterCustomizer/ Fixes #2822

springdoc-openapi-starter-common/src/main/java/org/springdoc/core/service/AbstractRequestService.java

@@ -434,8 +434,12 @@ protected void customiseParameter(Parameter parameter, ParameterInfo parameterIn
 			int index = operationParameters.indexOf(parameter);
 			for (ParameterCustomizer parameterCustomizer : parameterCustomizerList)
 				parameter = parameterCustomizer.customize(parameter, parameterInfo.getMethodParameter());
-			if (index != -1)
-				operationParameters.set(index, parameter);
+			if (index != -1) {
+				if (parameter == null)
+					operationParameters.remove(index);
+				else
+					operationParameters.set(index, parameter);
+			}
 		}
 	}
 
@@ -780,18 +784,18 @@ private boolean isRequestBodyParam(RequestMethod requestMethod, ParameterInfo pa
 	}
 
 	/**
- 	 * Checks whether Swagger's or Spring's RequestBody annotation is present on a parameter or method
-   	 *
+	 * Checks whether Swagger's or Spring's RequestBody annotation is present on a parameter or method
+	 *
 	 * @param methodParameter the method parameter
 	 * @return the boolean
- 	 */
+	 */
 	private boolean checkRequestBodyAnnotation(MethodParameter methodParameter) {
 		return methodParameter.hasParameterAnnotation(org.springframework.web.bind.annotation.RequestBody.class)
 				|| methodParameter.hasParameterAnnotation(io.swagger.v3.oas.annotations.parameters.RequestBody.class)
 				|| AnnotatedElementUtils.isAnnotated(Objects.requireNonNull(methodParameter.getParameter()), io.swagger.v3.oas.annotations.parameters.RequestBody.class)
 				|| AnnotatedElementUtils.isAnnotated(Objects.requireNonNull(methodParameter.getMethod()), io.swagger.v3.oas.annotations.parameters.RequestBody.class);
 	}
-	
+
 	/**
 	 * Check file boolean.
 	 *

springdoc-openapi-starter-webmvc-api/src/test/java/test/org/springdoc/api/v30/app234/HelloController.java

@@ -0,0 +1,40 @@
+/*
+ *
+ *  *
+ *  *  *
+ *  *  *  *
+ *  *  *  *  * Copyright 2019-2024 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.v30.app234;
+
+import test.org.springdoc.api.v30.app179.MyObj;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+
+@RestController
+public class HelloController {
+
+	@GetMapping("/test")
+	String test(MyObj obj) {
+		return obj.getContent();
+	}
+}

springdoc-openapi-starter-webmvc-api/src/test/java/test/org/springdoc/api/v30/app234/MyObj.java

@@ -0,0 +1,44 @@
+/*
+ *
+ *  *
+ *  *  *
+ *  *  *  *
+ *  *  *  *  * Copyright 2019-2024 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.v30.app234;
+
+public class MyObj {
+	private final String id;
+
+	private final String content;
+
+	public MyObj(String id, String content) {
+		this.id = id;
+		this.content = content;
+	}
+
+	public String getId() {
+		return id;
+	}
+
+	public String getContent() {
+		return content;
+	}
+}

springdoc-openapi-starter-webmvc-api/src/test/java/test/org/springdoc/api/v30/app234/MyPathParameterCustomizer.java

@@ -0,0 +1,39 @@
+/*
+ *
+ *  *
+ *  *  *
+ *  *  *  *
+ *  *  *  *  * Copyright 2019-2024 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.v30.app234;
+
+import io.swagger.v3.oas.models.parameters.Parameter;
+import org.springdoc.core.customizers.ParameterCustomizer;
+
+import org.springframework.core.MethodParameter;
+import org.springframework.stereotype.Component;
+
+@Component
+public class MyPathParameterCustomizer implements ParameterCustomizer {
+	@Override
+	public Parameter customize(Parameter parameterModel, MethodParameter methodParameter) {
+		return null;
+	}
+}

springdoc-openapi-starter-webmvc-api/src/test/java/test/org/springdoc/api/v30/app234/SpringDocApp234Test.java

@@ -0,0 +1,35 @@
+/*
+ *
+ *  *
+ *  *  *
+ *  *  *  *
+ *  *  *  *  * Copyright 2019-2024 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.v30.app234;
+
+import test.org.springdoc.api.v30.AbstractSpringDocV30Test;
+
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+public class SpringDocApp234Test extends AbstractSpringDocV30Test {
+
+	@SpringBootApplication
+	static class SpringDocTestApp {}
+}

springdoc-openapi-starter-webmvc-api/src/test/resources/results/3.0.1/app234.json

@@ -0,0 +1,38 @@
+{
+  "openapi": "3.0.1",
+  "info": {
+    "title": "OpenAPI definition",
+    "version": "v0"
+  },
+  "servers": [
+    {
+      "url": "http://localhost",
+      "description": "Generated server url"
+    }
+  ],
+  "paths": {
+    "/test": {
+      "get": {
+        "tags": [
+          "hello-controller"
+        ],
+        "operationId": "test",
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "*/*": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  },
+  "components": {
+    "schemas": {}
+  }
+}