Back off if a custom ApplicationAvailability bean is present

See gh-34347

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/availability/ApplicationAvailabilityAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2023 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.
@@ -17,6 +17,8 @@
 package org.springframework.boot.autoconfigure.availability;
 
 import org.springframework.boot.autoconfigure.AutoConfiguration;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.availability.ApplicationAvailability;
 import org.springframework.boot.availability.ApplicationAvailabilityBean;
 import org.springframework.context.annotation.Bean;
 
@@ -25,13 +27,15 @@ import org.springframework.context.annotation.Bean;
  * {@link ApplicationAvailabilityBean}.
  *
  * @author Brian Clozel
+ * @author Taeik Lim
  * @since 2.3.0
  */
 @AutoConfiguration
 public class ApplicationAvailabilityAutoConfiguration {
 
 	@Bean
-	public ApplicationAvailabilityBean applicationAvailability() {
+	@ConditionalOnMissingBean(ApplicationAvailability.class)
+	public ApplicationAvailability applicationAvailability() {
 		return new ApplicationAvailabilityBean();
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/availability/ApplicationAvailabilityAutoConfigurationTests.java

@@ -14,14 +14,17 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.autoconfigure.kubernetes;
+package org.springframework.boot.autoconfigure.availability;
 
 import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.autoconfigure.AutoConfigurations;
-import org.springframework.boot.autoconfigure.availability.ApplicationAvailabilityAutoConfiguration;
 import org.springframework.boot.availability.ApplicationAvailability;
+import org.springframework.boot.availability.AvailabilityChangeEvent;
+import org.springframework.boot.availability.AvailabilityState;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -29,6 +32,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * Tests for {@link ApplicationAvailabilityAutoConfiguration}
  *
  * @author Brian Clozel
+ * @author Taeik Lim
  */
 class ApplicationAvailabilityAutoConfigurationTests {
 
@@ -36,8 +40,41 @@ class ApplicationAvailabilityAutoConfigurationTests {
 		.withConfiguration(AutoConfigurations.of(ApplicationAvailabilityAutoConfiguration.class));
 
 	@Test
-	void providerIsPresent() {
-		this.contextRunner.run(((context) -> assertThat(context).hasSingleBean(ApplicationAvailability.class)));
+	void providerIsPresentWhenNotRegistered() {
+		this.contextRunner.run(((context) -> assertThat(context).hasSingleBean(ApplicationAvailability.class)
+			.hasBean("applicationAvailability")));
+	}
+
+	@Test
+	void providerIsPresentWithRegisteredOne() {
+		this.contextRunner.withUserConfiguration(ApplicationAvailabilityConfig.class)
+			.run(((context) -> assertThat(context).hasSingleBean(ApplicationAvailability.class)
+				.hasBean("customApplicationAvailability")));
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	static class ApplicationAvailabilityConfig {
+
+		@Bean
+		ApplicationAvailability customApplicationAvailability() {
+			return new ApplicationAvailability() {
+				@Override
+				public <S extends AvailabilityState> S getState(Class<S> stateType, S defaultState) {
+					return null;
+				}
+
+				@Override
+				public <S extends AvailabilityState> S getState(Class<S> stateType) {
+					return null;
+				}
+
+				@Override
+				public <S extends AvailabilityState> AvailabilityChangeEvent<S> getLastChangeEvent(Class<S> stateType) {
+					return null;
+				}
+			};
+		}
+
 	}
 
 }