Ensure local @crossorigin maxAge overrides global value

Prior to this commit, a method-level @crossorigin maxAge value did not
override a class-level @crossorigin maxAge value. This contradicts the
Javadoc for @Crossorgin which states the following.

    For those attributes where only a single value can be accepted such
    as allowCredentials and maxAge, the local overrides the global
    value.

This commit ensures that a method-level @crossorigin maxAge value
overrides a class-level @crossorigin maxAge value.

Closes gh-26619

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/RequestMappingHandlerMapping.java

@@ -338,7 +338,7 @@ else if (!allowCredentials.isEmpty()) {
 					"or an empty string (\"\"): current value is [" + allowCredentials + "]");
 		}
 
-		if (annotation.maxAge() >= 0 && config.getMaxAge() == null) {
+		if (annotation.maxAge() >= 0) {
 			config.setMaxAge(annotation.maxAge());
 		}
 	}

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/CrossOriginAnnotationIntegrationTests.java

@@ -29,6 +29,7 @@
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
+import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.CrossOrigin;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PostMapping;
@@ -37,6 +38,7 @@
 import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.client.HttpClientErrorException;
 import org.springframework.web.client.RestTemplate;
+import org.springframework.web.cors.CorsConfiguration;
 import org.springframework.web.reactive.config.EnableWebFlux;
 import org.springframework.web.testfixture.http.server.reactive.bootstrap.HttpServer;
 
@@ -257,6 +259,19 @@ void ambiguousProducesPreflightRequest(HttpServer httpServer) throws Exception {
 		assertThat(entity.getHeaders().getAccessControlAllowCredentials()).isTrue();
 	}
 
+	@ParameterizedHttpServerTest
+	void maxAgeWithDefaultOrigin(HttpServer httpServer) throws Exception {
+		startServer(httpServer);
+
+		this.headers.add(HttpHeaders.ACCESS_CONTROL_REQUEST_METHOD, "GET");
+		ResponseEntity<String> entity = performOptions("/classAge", this.headers, String.class);
+		assertThat(entity.getStatusCode()).isEqualTo(HttpStatus.OK);
+		assertThat(entity.getHeaders().getAccessControlMaxAge()).isEqualTo(10);
+
+		entity = performOptions("/methodAge", this.headers, String.class);
+		assertThat(entity.getStatusCode()).isEqualTo(HttpStatus.OK);
+		assertThat(entity.getHeaders().getAccessControlMaxAge()).isEqualTo(100);
+	}
 
 	@Configuration
 	@EnableWebFlux
@@ -361,4 +376,21 @@ public String baz() {
 		}
 	}
 
+	@RestController
+	@CrossOrigin(maxAge = 10)
+	private static class MaxAgeWithDefaultOriginController {
+
+		@CrossOrigin
+		@GetMapping(path = "/classAge")
+		public String classAge() {
+			return "classAge";
+		}
+
+		@CrossOrigin(maxAge = 100)
+		@GetMapping(path = "/methodAge")
+		public String methodAge() {
+			return "methodAge";
+		}
+	}
+
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMapping.java

@@ -456,7 +456,7 @@ else if (!allowCredentials.isEmpty()) {
 					"or an empty string (\"\"): current value is [" + allowCredentials + "]");
 		}
 
-		if (annotation.maxAge() >= 0 && config.getMaxAge() == null) {
+		if (annotation.maxAge() >= 0) {
 			config.setMaxAge(annotation.maxAge());
 		}
 	}

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/CrossOriginTests.java

@@ -310,6 +310,27 @@ public void preFlightRequestWithoutRequestMethodHeader() throws Exception {
 		assertThat(this.handlerMapping.getHandler(request)).isNull();
 	}
 
+	@Test
+	public void maxAgeWithDefaultOrigin() throws Exception {
+		this.handlerMapping.registerHandler(new MaxAgeWithDefaultOriginController());
+
+		this.request.setRequestURI("/classAge");
+		HandlerExecutionChain chain = this.handlerMapping.getHandler(request);
+		CorsConfiguration config = getCorsConfiguration(chain, false);
+		assertThat(config).isNotNull();
+		assertThat(config.getAllowedMethods()).containsExactly("GET");
+		assertThat(config.getAllowedOrigins()).containsExactly("*");
+		assertThat(config.getMaxAge()).isEqualTo(10);
+
+		this.request.setRequestURI("/methodAge");
+		chain = this.handlerMapping.getHandler(request);
+		config = getCorsConfiguration(chain, false);
+		assertThat(config).isNotNull();
+		assertThat(config.getAllowedMethods()).containsExactly("GET");
+		assertThat(config.getAllowedOrigins()).containsExactly("*");
+		assertThat(config.getMaxAge()).isEqualTo(100);
+	}
+
 
 	private CorsConfiguration getCorsConfiguration(HandlerExecutionChain chain, boolean isPreFlightRequest) {
 		if (isPreFlightRequest) {
@@ -425,7 +446,21 @@ public void bar() {
 		@RequestMapping(path = "/baz", method = RequestMethod.GET)
 		public void baz() {
 		}
+	}
+
+	@Controller
+	@CrossOrigin(maxAge = 10)
+	private static class MaxAgeWithDefaultOriginController {
 
+		@CrossOrigin
+		@RequestMapping(path = "/classAge", method = RequestMethod.GET)
+		public void classAge() {
+		}
+
+		@CrossOrigin(maxAge = 100)
+		@RequestMapping(path = "/methodAge", method = RequestMethod.GET)
+		public void methodAge() {
+		}
 	}