Allow configuration of session management through nested builder

Issue: gh-5557

config/src/test/java/org/springframework/security/config/annotation/web/configurers/SessionManagementConfigurerTests.java

@@ -54,6 +54,7 @@ import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
+import static org.springframework.security.config.Customizer.withDefaults;
 import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.csrf;
 import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.httpBasic;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
@@ -262,6 +263,73 @@ public class SessionManagementConfigurerTests {
 		}
 	}
 
+	@Test
+	public void loginWhenUserLoggedInAndMaxSessionsOneInLambdaThenLoginPrevented() throws Exception {
+		this.spring.register(ConcurrencyControlInLambdaConfig.class).autowire();
+
+		this.mvc.perform(post("/login")
+				.with(csrf())
+				.param("username", "user")
+				.param("password", "password"));
+
+		this.mvc.perform(post("/login")
+				.with(csrf())
+				.param("username", "user")
+				.param("password", "password"))
+				.andExpect(status().isFound())
+				.andExpect(redirectedUrl("/login?error"));
+	}
+
+	@EnableWebSecurity
+	static class ConcurrencyControlInLambdaConfig extends WebSecurityConfigurerAdapter {
+		@Override
+		public void configure(HttpSecurity http) throws Exception {
+			// @formatter:off
+			http
+				.formLogin(withDefaults())
+				.sessionManagement(sessionManagement ->
+					sessionManagement
+						.maximumSessions(1)
+						.maxSessionsPreventsLogin(true)
+				);
+			// @formatter:on
+		}
+
+		@Override
+		protected void configure(AuthenticationManagerBuilder auth) throws Exception {
+			// @formatter:off
+			auth
+				.inMemoryAuthentication()
+					.withUser(PasswordEncodedUser.user());
+			// @formatter:on
+		}
+	}
+
+	@Test
+	public void requestWhenSessionCreationPolicyStateLessInLambdaThenNoSessionCreated() throws Exception {
+		this.spring.register(SessionCreationPolicyStateLessInLambdaConfig.class).autowire();
+
+		MvcResult mvcResult = this.mvc.perform(get("/"))
+				.andReturn();
+		HttpSession session = mvcResult.getRequest().getSession(false);
+
+		assertThat(session).isNull();
+	}
+
+	@EnableWebSecurity
+	static class SessionCreationPolicyStateLessInLambdaConfig extends WebSecurityConfigurerAdapter {
+		@Override
+		protected void configure(HttpSecurity http) throws Exception {
+			// @formatter:off
+			http
+				.sessionManagement(sessionManagement ->
+					sessionManagement
+						.sessionCreationPolicy(SessionCreationPolicy.STATELESS)
+				);
+			// @formatter:on
+		}
+	}
+
 	@Test
 	public void configureWhenRegisteringObjectPostProcessorThenInvokedOnSessionManagementFilter() {
 		ObjectPostProcessorConfig.objectPostProcessor = spy(ReflectingObjectPostProcessor.class);