feat: resolve annotations that are within Optional parameters

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

@@ -431,7 +431,7 @@ Schema calculateSchema(Components components, ParameterInfo parameterInfo, Reque
 	 */
 	private TypeAndTypeAnnotations resolveTypeAndTypeAnnotationsForParameter(MethodParameter methodParameter) {
 		if (methodParameter instanceof DelegatingMethodParameter delegatingMethodParameter
-				&& delegatingMethodParameter.getField() != null) {
+			&& delegatingMethodParameter.getField() != null) {
 			AnnotatedType annotated = delegatingMethodParameter.getField().getAnnotatedType();
 			Type type = GenericTypeResolver.resolveType(annotated.getType(), methodParameter.getContainingClass());
 			return new TypeAndTypeAnnotations(type, Arrays.asList(annotationsFromAnnotatedTypeArguments(annotated)));
@@ -448,7 +448,30 @@ private TypeAndTypeAnnotations resolveTypeAndTypeAnnotationsForParameter(MethodP
 					: new TypeAndTypeAnnotations(type, new ArrayList<>());
 		}
 
-		return new TypeAndTypeAnnotations(type, Arrays.asList(methodParameter.getParameterType().getAnnotations()));
+		List<Annotation> typeAnnotations = new ArrayList<>(Arrays.asList(methodParameter.getParameterType().getAnnotations()));
+		if (Optional.class.isAssignableFrom(methodParameter.getParameterType())) {
+			typeAnnotations.addAll(Arrays.asList(annotationsFromAnnotatedTypeArguments(getParameterAnnotatedType(methodParameter))));
+		}
+		return new TypeAndTypeAnnotations(type, typeAnnotations);
+	}
+
+	/**
+	 * Resolves the {@link AnnotatedType} of a method parameter so that annotations declared on its
+	 * generic type arguments (for example inside an {@link Optional}) can be inspected.
+	 *
+	 * @param methodParameter the method parameter
+	 * @return the annotated type, or {@code null} if it cannot be resolved
+	 */
+	private static AnnotatedType getParameterAnnotatedType(MethodParameter methodParameter) {
+		int index = methodParameter.getParameterIndex();
+		if (index < 0) {
+			return null;
+		}
+		java.lang.reflect.Parameter[] parameters = methodParameter.getExecutable().getParameters();
+		if (index >= parameters.length) {
+			return null;
+		}
+		return parameters[index].getAnnotatedType();
 	}
 
 	/**

springdoc-openapi-starter-webmvc-api/src/test/java/test/org/springdoc/api/v30/app270/HelloController.java

@@ -0,0 +1,61 @@
+/*
+ *
+ *  *
+ *  *  *
+ *  *  *  *
+ *  *  *  *  * Copyright 2019-2026 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.app270;
+
+import java.util.List;
+import java.util.Optional;
+
+import jakarta.validation.constraints.Min;
+import jakarta.validation.constraints.Pattern;
+import jakarta.validation.constraints.Size;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * Verifies that Bean Validation constraint annotations declared on the type argument of an
+ * {@link Optional} controller parameter are read and applied to the generated OpenAPI schema.
+ */
+@RestController
+public class HelloController {
+
+	@GetMapping("/api/string")
+	String testString(@RequestParam Optional<@Size(min = 2, max = 10) @Pattern(regexp = "[a-z]+") String> name) {
+		return null;
+	}
+
+	@GetMapping("/api/integer")
+	String testInteger(@RequestParam Optional<@Min(5) Integer> age) {
+		return null;
+	}
+
+	@GetMapping("/api/list")
+	String testList(@RequestParam @Size(min = 2, max = 10) List<@Pattern(regexp = "[a-z]+") String> age) {
+		return null;
+	}
+
+}
+

springdoc-openapi-starter-webmvc-api/src/test/java/test/org/springdoc/api/v30/app270/SpringDocApp270Test.java

@@ -0,0 +1,39 @@
+/*
+ *
+ *  *
+ *  *  *
+ *  *  *  *
+ *  *  *  *  * Copyright 2019-2026 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.app270;
+
+import test.org.springdoc.api.v30.AbstractSpringDocV30Test;
+
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+public class SpringDocApp270Test extends AbstractSpringDocV30Test {
+
+
+	@SpringBootApplication
+	static class SpringDocTestApp {
+
+	}
+}
+

springdoc-openapi-starter-webmvc-api/src/test/java/test/org/springdoc/api/v31/app270/HelloController.java

@@ -0,0 +1,61 @@
+/*
+ *
+ *  *
+ *  *  *
+ *  *  *  *
+ *  *  *  *  * Copyright 2019-2026 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.v31.app270;
+
+import java.util.List;
+import java.util.Optional;
+
+import jakarta.validation.constraints.Min;
+import jakarta.validation.constraints.Pattern;
+import jakarta.validation.constraints.Size;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * Verifies that Bean Validation constraint annotations declared on the type argument of an
+ * {@link Optional} controller parameter are read and applied to the generated OpenAPI schema.
+ */
+@RestController
+public class HelloController {
+
+	@GetMapping("/api/string")
+	String testString(@RequestParam Optional<@Size(min = 2, max = 10) @Pattern(regexp = "[a-z]+") String> name) {
+		return null;
+	}
+
+	@GetMapping("/api/integer")
+	String testInteger(@RequestParam Optional<@Min(5) Integer> age) {
+		return null;
+	}
+
+	@GetMapping("/api/list")
+	String testList(@RequestParam @Size(min = 2, max = 10) List<@Pattern(regexp = "[a-z]+") String> age) {
+		return null;
+	}
+
+}
+

springdoc-openapi-starter-webmvc-api/src/test/java/test/org/springdoc/api/v31/app270/SpringDocApp270Test.java

@@ -0,0 +1,39 @@
+/*
+ *
+ *  *
+ *  *  *
+ *  *  *  *
+ *  *  *  *  * Copyright 2019-2026 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.v31.app270;
+
+import test.org.springdoc.api.v31.AbstractSpringDocTest;
+
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+public class SpringDocApp270Test extends AbstractSpringDocTest {
+
+
+	@SpringBootApplication
+	static class SpringDocTestApp {
+
+	}
+}
+

springdoc-openapi-starter-webmvc-api/src/test/resources/results/3.0.1/app270.json

@@ -0,0 +1,118 @@
+{
+  "openapi": "3.0.1",
+  "info": {
+    "title": "OpenAPI definition",
+    "version": "v0"
+  },
+  "servers": [
+    {
+      "url": "http://localhost",
+      "description": "Generated server url"
+    }
+  ],
+  "paths": {
+    "/api/string": {
+      "get": {
+        "tags": [
+          "hello-controller"
+        ],
+        "operationId": "testString",
+        "parameters": [
+          {
+            "name": "name",
+            "in": "query",
+            "required": false,
+            "schema": {
+              "maxLength": 10,
+              "minLength": 2,
+              "pattern": "[a-z]+",
+              "type": "string"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "*/*": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            }
+          }
+        }
+      }
+    },
+    "/api/list": {
+      "get": {
+        "tags": [
+          "hello-controller"
+        ],
+        "operationId": "testList",
+        "parameters": [
+          {
+            "name": "age",
+            "in": "query",
+            "required": true,
+            "schema": {
+              "maxItems": 10,
+              "minItems": 2,
+              "type": "array",
+              "items": {
+                "pattern": "[a-z]+",
+                "type": "string"
+              }
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "*/*": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            }
+          }
+        }
+      }
+    },
+    "/api/integer": {
+      "get": {
+        "tags": [
+          "hello-controller"
+        ],
+        "operationId": "testInteger",
+        "parameters": [
+          {
+            "name": "age",
+            "in": "query",
+            "required": false,
+            "schema": {
+              "minimum": 5,
+              "type": "integer",
+              "format": "int32"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "*/*": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  },
+  "components": {}
+}
+