Add Partitioned Cookie Support to DefaultCookieSerializer

Closes gh-2787

spring-session-core/src/main/java/org/springframework/session/web/http/DefaultCookieSerializer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2021 the original author or authors.
+ * Copyright 2014-2024 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.
@@ -86,6 +86,8 @@ public class DefaultCookieSerializer implements CookieSerializer {
 
 	private String sameSite = "Lax";
 
+	private boolean partitioned;
+
 	/*
 	 * @see
 	 * org.springframework.session.web.http.CookieSerializer#readCookieValues(jakarta.
@@ -153,6 +155,9 @@ public class DefaultCookieSerializer implements CookieSerializer {
 		if (this.sameSite != null) {
 			sb.append("; SameSite=").append(this.sameSite);
 		}
+		if (this.partitioned) {
+			sb.append("; Partitioned");
+		}
 		response.addHeader("Set-Cookie", sb.toString());
 	}
 
@@ -444,4 +449,12 @@ public class DefaultCookieSerializer implements CookieSerializer {
 		return this.rememberMeRequestAttribute;
 	}
 
+	/**
+	 * Allows defining whether the generated cookie carries the Partitioned attribute
+	 * @since 3.4
+	 */
+	public void setPartitioned(boolean partitioned) {
+		this.partitioned = partitioned;
+	}
+
 }

spring-session-core/src/test/java/org/springframework/session/web/http/DefaultCookieSerializerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2021 the original author or authors.
+ * Copyright 2014-2024 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.
@@ -460,6 +460,13 @@ class DefaultCookieSerializerTests {
 		assertThat(getCookie().getSameSite()).isNull();
 	}
 
+	@Test
+	void writeCookieWhenPartitionedTrueThenSetPartitionedAttribute() {
+		this.serializer.setPartitioned(true);
+		this.serializer.writeCookieValue(cookieValue(this.sessionId));
+		assertThat(getCookie().isPartitioned()).isTrue();
+	}
+
 	void setCookieName(String cookieName) {
 		this.cookieName = cookieName;
 		this.serializer.setCookieName(cookieName);

spring-session-docs/modules/ROOT/pages/whats-new.adoc

@@ -1,4 +1,3 @@
-= What's New
+= What's New in 3.4
 
-- xref:configuration/common.adoc#changing-how-session-ids-are-generated[docs] - https://github.com/spring-projects/spring-session/issues/11[gh-11] - Introduce `SessionIdGenerator` to allow custom session id generation
-- xref:configuration/redis.adoc#configuring-redis-session-mapper[docs] - https://github.com/spring-projects/spring-session/issues/2021[gh-2021] - Allow safe deserialization of Redis sessions
+- https://github.com/spring-projects/spring-session/issues/2787[gh-2787] - Add Partitioned Cookie Support to `DefaultCookieSerializer`