Fix missing Partitioned cookie support in reactive HTTP clients

This commit adds support for the Partitioned cookie attribute in the
reactive HTTP clients that support this: Reactor and HttpComponents.

Closes gh-34521

Signed-off-by: Rhett CfZhuang <dark.momo985@gmail.com>
[brian.clozel@broadcom.com: rework tests and support HttpComponents]
Signed-off-by: Brian Clozel <brian.clozel@broadcom.com>

spring-web/src/main/java/org/springframework/http/client/reactive/HttpComponentsClientHttpResponse.java

@@ -90,6 +90,7 @@ class HttpComponentsClientHttpResponse extends AbstractClientHttpResponse {
 										.maxAge(getMaxAgeSeconds(cookie))
 										.secure(cookie.isSecure())
 										.httpOnly(cookie.containsAttribute("httponly"))
+										.partitioned(cookie.containsAttribute("partitioned"))
 										.sameSite(cookie.getAttribute("samesite"))
 										.build());
 					}

spring-web/src/main/java/org/springframework/http/client/reactive/ReactorClientHttpResponse.java

@@ -148,6 +148,7 @@ class ReactorClientHttpResponse implements ClientHttpResponse {
 								.secure(cookie.isSecure())
 								.httpOnly(cookie.isHttpOnly())
 								.sameSite(getSameSite(cookie))
+								.partitioned(getPartitioned(cookie))
 								.build()));
 		return CollectionUtils.unmodifiableMultiValueMap(result);
 	}
@@ -160,6 +161,13 @@ class ReactorClientHttpResponse implements ClientHttpResponse {
 		return null;
 	}
 
+	private static boolean getPartitioned(Cookie cookie) {
+		if (cookie instanceof DefaultCookie defaultCookie) {
+			return defaultCookie.isPartitioned();
+		}
+		return false;
+	}
+
 	/**
 	 * Called by {@link ReactorClientHttpConnector} when a cancellation is detected
 	 * but the content has not been subscribed to. If the subscription never

spring-web/src/test/java/org/springframework/http/client/reactive/ClientHttpConnectorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -41,6 +41,7 @@ import okhttp3.mockwebserver.RecordedRequest;
 import okio.Buffer;
 import org.apache.hc.client5.http.impl.async.HttpAsyncClientBuilder;
 import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Assumptions;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Named;
 import org.junit.jupiter.api.Test;
@@ -201,6 +202,25 @@ class ClientHttpConnectorTests {
 				.verifyComplete();
 	}
 
+	@ParameterizedConnectorTest
+	void partitionedCookieSupport(ClientHttpConnector connector) {
+		Assumptions.assumeFalse(connector instanceof JettyClientHttpConnector, "Jetty client does not support partitioned cookies");
+		Assumptions.assumeFalse(connector instanceof JdkClientHttpConnector, "JDK client does not support partitioned cookies");
+		prepareResponse(response -> {
+			response.setResponseCode(200);
+			response.addHeader("Set-Cookie", "id=test; Partitioned;");
+		});
+		Mono<ClientHttpResponse> futureResponse =
+				connector.connect(HttpMethod.GET, this.server.url("/").uri(), ReactiveHttpOutputMessage::setComplete);
+		StepVerifier.create(futureResponse)
+				.assertNext(response -> {
+							assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
+							assertThat(response.getCookies().getFirst("id").isPartitioned()).isTrue();
+						}
+				)
+				.verifyComplete();
+	}
+
 	@Test
 	void disableCookieWithHttpComponents() {
 		ClientHttpConnector connector = new HttpComponentsClientHttpConnector(