Do not change availability on close unless context is active

Previously, an AvailabilityChangeEvent was published when the servlet
and reactive web server application contexts were closed, irrespective
of whether or not the context was active. This caused problems when
the context was not active due to a refresh failure as the event
publication could then trigger bean creation and post-processing that
relied upon beans that had been destroyed when cleaning up after the
refresh failure. The most commonly seen symptom was a missing
importRegistry bean that is required by ImportAwareBeanPostProcessor.

This commit updates the two web server application contexts to only
publish the availability change event if the context is active.

Fixes gh-21588

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/reactive/context/ReactiveWebServerApplicationContext.java

@@ -136,7 +136,9 @@ protected HttpHandler getHttpHandler() {
 
 	@Override
 	protected void doClose() {
-		AvailabilityChangeEvent.publish(this, ReadinessState.REFUSING_TRAFFIC);
+		if (this.isActive()) {
+			AvailabilityChangeEvent.publish(this, ReadinessState.REFUSING_TRAFFIC);
+		}
 		super.doClose();
 	}
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/servlet/context/ServletWebServerApplicationContext.java

@@ -164,7 +164,9 @@ protected void onRefresh() {
 
 	@Override
 	protected void doClose() {
-		AvailabilityChangeEvent.publish(this, ReadinessState.REFUSING_TRAFFIC);
+		if (this.isActive()) {
+			AvailabilityChangeEvent.publish(this, ReadinessState.REFUSING_TRAFFIC);
+		}
 		super.doClose();
 	}
 

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/reactive/context/ReactiveWebServerApplicationContextTests.java

@@ -24,6 +24,7 @@
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.boot.availability.AvailabilityChangeEvent;
 import org.springframework.boot.availability.ReadinessState;
@@ -141,6 +142,18 @@ void whenContextIsClosedThenApplicationAvailabilityChangesToRefusingTraffic() {
 				.isEqualTo(ReadinessState.REFUSING_TRAFFIC);
 	}
 
+	@Test
+	void whenContextIsNotActiveThenCloseDoesNotChangeTheApplicationAvailability() {
+		addWebServerFactoryBean();
+		addHttpHandlerBean();
+		TestApplicationListener listener = new TestApplicationListener();
+		this.context.addApplicationListener(listener);
+		this.context.registerBeanDefinition("refreshFailure", new RootBeanDefinition(RefreshFailure.class));
+		assertThatExceptionOfType(BeanCreationException.class).isThrownBy(this.context::refresh);
+		this.context.close();
+		assertThat(listener.receivedEvents()).isEmpty();
+	}
+
 	@Test
 	void whenTheContextIsRefreshedThenASubsequentRefreshAttemptWillFail() {
 		addWebServerFactoryBean();
@@ -186,4 +199,12 @@ List<ApplicationEvent> receivedEvents() {
 
 	}
 
+	static class RefreshFailure {
+
+		RefreshFailure() {
+			throw new RuntimeException("Fail refresh");
+		}
+
+	}
+
 }

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/servlet/context/ServletWebServerApplicationContextTests.java

@@ -182,6 +182,17 @@ void applicationIsUnreadyDuringShutdown() {
 				ContextClosedEvent.class);
 	}
 
+	@Test
+	void whenContextIsNotActiveThenCloseDoesNotChangeTheApplicationAvailability() {
+		addWebServerFactoryBean();
+		TestApplicationListener listener = new TestApplicationListener();
+		this.context.addApplicationListener(listener);
+		this.context.registerBeanDefinition("refreshFailure", new RootBeanDefinition(RefreshFailure.class));
+		assertThatExceptionOfType(BeanCreationException.class).isThrownBy(this.context::refresh);
+		this.context.close();
+		assertThat(listener.receivedEvents()).isEmpty();
+	}
+
 	@Test
 	void cannotSecondRefresh() {
 		addWebServerFactoryBean();
@@ -531,4 +542,12 @@ ServletRequest getRequest() {
 
 	}
 
+	static class RefreshFailure {
+
+		RefreshFailure() {
+			throw new RuntimeException("Fail refresh");
+		}
+
+	}
+
 }