Polish contribution

See gh-35013

Author: sbrannen

spring-web/src/main/java/org/springframework/web/server/session/InMemoryWebSessionStore.java

@@ -283,7 +283,7 @@ public Mono<Void> save() {
 		private void checkMaxSessionsLimit() {
 			if (sessions.size() >= maxSessions) {
 				expiredSessionChecker.removeExpiredSessions(clock.instant());
-				if (sessions.size() >= maxSessions && !sessions.containsKey(this.getId())) {
+				if (sessions.size() >= maxSessions && !sessions.containsKey(this.id.get())) {
 					throw new IllegalStateException("Max sessions limit reached: " + sessions.size());
 				}
 			}

spring-web/src/test/java/org/springframework/web/server/session/InMemoryWebSessionStoreTests.java

@@ -160,21 +160,40 @@ void maxSessions() {
 
 	@Test
 	void updateSession() {
-		WebSession oneWebSession = insertSession();
+		WebSession session = insertSession();
 
-		StepVerifier.create(oneWebSession.save())
+		StepVerifier.create(session.save())
 				.expectComplete()
 				.verify();
 	}
 
-	@Test
-	void updateSession_whenMaxSessionsReached() {
-		WebSession onceWebSession = insertSession();
-		IntStream.range(1, 10000).forEach(i -> insertSession());
+	@Test  // gh-35013
+	void updateSessionAfterMaxSessionLimitIsExceeded() {
+		this.store.setMaxSessions(10);
+
+		WebSession session = insertSession();
+		assertNumSessions(1);
+
+		IntStream.rangeClosed(1, 9).forEach(i -> insertSession());
+		assertNumSessions(10);
+
+		// Updating an existing session should succeed.
+		StepVerifier.create(session.save())
+				.expectComplete()
+				.verify();
+		assertNumSessions(10);
+
+		// Saving an additional new session should fail.
+		assertThatIllegalStateException()
+				.isThrownBy(this::insertSession)
+				.withMessage("Max sessions limit reached: 10");
+		assertNumSessions(10);
 
-		StepVerifier.create(onceWebSession.save())
+		// Updating an existing session again should still succeed.
+		StepVerifier.create(session.save())
 				.expectComplete()
 				.verify();
+		assertNumSessions(10);
 	}