Delay property source initialization till LoggingSystem is initialized

Previously, the initialization of StandardServletEnvironment's
property sources in SpringBootServletInitializer led to debug logging
calls being made before the LoggingSystem had been initialized. As a
result, the system's default configuration was used and, in the case
of Logback at least, the debug logging was output to System.out
in a war deployment.

This commit updates SpringBootServletInitializer to delay the
initialization of StandardServletEnvironment's property sources until
after the LoggingSystem has been initialized, but still in time for
active profiles to be configured via servlet context parameters
(see gh-9972).

Closes gh-13736

Author: wilkinsona

spring-boot/src/main/java/org/springframework/boot/web/support/SpringBootServletInitializer.java

@@ -29,15 +29,19 @@
 import org.springframework.boot.builder.ParentContextApplicationContextInitializer;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext;
+import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
 import org.springframework.boot.web.servlet.ServletContextInitializer;
 import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationListener;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.core.Ordered;
 import org.springframework.core.annotation.AnnotationUtils;
+import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.util.Assert;
 import org.springframework.web.WebApplicationInitializer;
+import org.springframework.web.context.ConfigurableWebEnvironment;
 import org.springframework.web.context.ContextLoaderListener;
 import org.springframework.web.context.WebApplicationContext;
-import org.springframework.web.context.support.StandardServletEnvironment;
 
 /**
  * An opinionated {@link WebApplicationInitializer} to run a {@link SpringApplication}
@@ -104,9 +108,6 @@ public void contextInitialized(ServletContextEvent event) {
 	protected WebApplicationContext createRootApplicationContext(
 			ServletContext servletContext) {
 		SpringApplicationBuilder builder = createSpringApplicationBuilder();
-		StandardServletEnvironment environment = new StandardServletEnvironment();
-		environment.initPropertySources(servletContext, null);
-		builder.environment(environment);
 		builder.main(getClass());
 		ApplicationContext parent = getExistingRootWebApplicationContext(servletContext);
 		if (parent != null) {
@@ -119,6 +120,7 @@ protected WebApplicationContext createRootApplicationContext(
 				new ServletContextApplicationContextInitializer(servletContext));
 		builder.contextClass(AnnotationConfigEmbeddedWebApplicationContext.class);
 		builder = configure(builder);
+		builder.listeners(new WebEnvironmentPropertySourceInitializer(servletContext));
 		SpringApplication application = builder.build();
 		if (application.getSources().isEmpty() && AnnotationUtils
 				.findAnnotation(getClass(), Configuration.class) != null) {
@@ -177,4 +179,30 @@ protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
 		return builder;
 	}
 
+	private static final class WebEnvironmentPropertySourceInitializer
+			implements ApplicationListener<ApplicationEnvironmentPreparedEvent>, Ordered {
+
+		private final ServletContext servletContext;
+
+		private WebEnvironmentPropertySourceInitializer(ServletContext servletContext) {
+			this.servletContext = servletContext;
+		}
+
+		@Override
+		public void onApplicationEvent(ApplicationEnvironmentPreparedEvent event) {
+			ConfigurableEnvironment environment = event.getEnvironment();
+			if (environment instanceof ConfigurableWebEnvironment) {
+				((ConfigurableWebEnvironment) environment)
+						.initPropertySources(this.servletContext, null);
+			}
+
+		}
+
+		@Override
+		public int getOrder() {
+			return Ordered.HIGHEST_PRECEDENCE;
+		}
+
+	}
+
 }

spring-boot/src/test/java/org/springframework/boot/web/support/SpringBootServletInitializerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -22,6 +22,7 @@
 import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
 
+import org.junit.After;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
@@ -33,6 +34,7 @@
 import org.springframework.boot.context.embedded.EmbeddedServletContainerFactory;
 import org.springframework.boot.context.embedded.undertow.UndertowEmbeddedServletContainerFactory;
 import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
+import org.springframework.boot.testutil.InternalOutputCapture;
 import org.springframework.boot.web.servlet.ServletContextInitializer;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.ConfigurableApplicationContext;
@@ -59,10 +61,19 @@ public class SpringBootServletInitializerTests {
 	@Rule
 	public ExpectedException thrown = ExpectedException.none();
 
+	@Rule
+	public InternalOutputCapture output = new InternalOutputCapture();
+
 	private ServletContext servletContext = new MockServletContext();
 
 	private SpringApplication application;
 
+	@After
+	public void verifyLoggingOutput() {
+		assertThat(this.output.toString())
+				.doesNotContain(StandardServletEnvironment.class.getSimpleName());
+	}
+
 	@Test
 	public void failsWithoutConfigure() throws Exception {
 		this.thrown.expect(IllegalStateException.class);