Prevent failure of web app with parent context

ServerProperties formerly had an @OnMissingBeanCondition
that didn't restrict the hierarchy. It also asserts that
the current context (not including parents) contains such
a bean. This led to an inevitable failure when there was
an existing instance in the parent context.

Fixed by a) searching only the current context, b) not
adding a ServerProperties bean if the context is not a
web app.

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/web/BasicErrorControllerSpecialIntegrationTests.java

@@ -20,7 +20,6 @@ import org.junit.After;
 import org.junit.Test;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
-import org.springframework.boot.autoconfigure.web.ServerPropertiesAutoConfiguration;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.http.MediaType;
@@ -78,8 +77,7 @@ public class BasicErrorControllerSpecialIntegrationTests {
 	}
 
 	@Configuration
-	// TODO: fix this so it doesn't need to be excluded
+	@EnableAutoConfiguration
-	@EnableAutoConfiguration(exclude = ServerPropertiesAutoConfiguration.class)
 	protected static class ParentConfiguration {
 
 	}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ServerPropertiesAutoConfiguration.java

@@ -19,6 +19,8 @@ package org.springframework.boot.autoconfigure.web;
 import org.springframework.beans.BeansException;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
+import org.springframework.boot.autoconfigure.condition.SearchStrategy;
 import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainerFactory;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
@@ -38,13 +40,14 @@ import org.springframework.util.StringUtils;
  */
 @Configuration
 @EnableConfigurationProperties
+@ConditionalOnWebApplication
 public class ServerPropertiesAutoConfiguration implements ApplicationContextAware,
 		EmbeddedServletContainerCustomizer {
 
 	private ApplicationContext applicationContext;
 
 	@Bean(name = "org.springframework.boot.autoconfigure.web.ServerProperties")
-	@ConditionalOnMissingBean
+	@ConditionalOnMissingBean(search = SearchStrategy.CURRENT)
 	public ServerProperties serverProperties() {
 		return new ServerProperties();
 	}