Don't replace existing web scopes

Update EmbeddedWebApplicationContext to store then restore any existing
web scopes that may have been registered. This allows custom web scopes
to be registered in an ApplicationContextInitializer.

Fixes gh-2082

spring-boot/src/main/java/org/springframework/boot/context/embedded/EmbeddedWebApplicationContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2013 the original author or authors.
+ * Copyright 2012-2015 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.
@@ -17,7 +17,12 @@
 package org.springframework.boot.context.embedded;
 
 import java.util.Collection;
+import java.util.Collections;
 import java.util.EventListener;
+import java.util.HashMap;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Set;
 
 import javax.servlet.Filter;
 import javax.servlet.Servlet;
@@ -29,6 +34,7 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.beans.factory.config.Scope;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextException;
 import org.springframework.core.io.Resource;
@@ -77,6 +83,9 @@ import org.springframework.web.context.support.WebApplicationContextUtils;
  */
 public class EmbeddedWebApplicationContext extends GenericWebApplicationContext {
 
+	private static final Log logger = LogFactory
+			.getLog(EmbeddedWebApplicationContext.class);
+
 	/**
 	 * Constant value for the DispatcherServlet bean name. A Servlet bean with this name
 	 * is deemed to be the "main" servlet and is automatically given a mapping of "/" by
@@ -194,17 +203,25 @@ public class EmbeddedWebApplicationContext extends GenericWebApplicationContext
 		return new ServletContextInitializer() {
 			@Override
 			public void onStartup(ServletContext servletContext) throws ServletException {
+				selfInitialize(servletContext);
+			}
+		};
+	}
+
+	private void selfInitialize(ServletContext servletContext) throws ServletException {
 		prepareEmbeddedWebApplicationContext(servletContext);
-				WebApplicationContextUtils.registerWebApplicationScopes(getBeanFactory(),
+		ConfigurableListableBeanFactory beanFactory = getBeanFactory();
+		ExistingWebApplicationScopes existingScopes = new ExistingWebApplicationScopes(
+				beanFactory);
+		WebApplicationContextUtils.registerWebApplicationScopes(beanFactory,
 				getServletContext());
-				WebApplicationContextUtils.registerEnvironmentBeans(getBeanFactory(),
+		existingScopes.restore();
+		WebApplicationContextUtils.registerEnvironmentBeans(beanFactory,
 				getServletContext());
 		for (ServletContextInitializer beans : getServletContextInitializerBeans()) {
 			beans.onStartup(servletContext);
 		}
 	}
-		};
-	}
 
 	/**
 	 * Returns {@link ServletContextInitializer}s that should be used with the embedded
@@ -319,4 +336,45 @@ public class EmbeddedWebApplicationContext extends GenericWebApplicationContext
 		return this.embeddedServletContainer;
 	}
 
+	/**
+	 * Utility class to store and restore any user defined scopes. This allow scopes to be
+	 * registered in an ApplicationContextInitializer in the same way as they would in a
+	 * classic non-embedded web application context.
+	 */
+	public static class ExistingWebApplicationScopes {
+
+		private static final Set<String> SCOPES;
+		static {
+			Set<String> scopes = new LinkedHashSet<String>();
+			scopes.add(WebApplicationContext.SCOPE_REQUEST);
+			scopes.add(WebApplicationContext.SCOPE_SESSION);
+			scopes.add(WebApplicationContext.SCOPE_GLOBAL_SESSION);
+			SCOPES = Collections.unmodifiableSet(scopes);
+		}
+
+		private final ConfigurableListableBeanFactory beanFactory;
+
+		private final Map<String, Scope> scopes = new HashMap<String, Scope>();
+
+		public ExistingWebApplicationScopes(ConfigurableListableBeanFactory beanFactory) {
+			this.beanFactory = beanFactory;
+			for (String scopeName : SCOPES) {
+				Scope scope = beanFactory.getRegisteredScope(scopeName);
+				if (scope != null) {
+					this.scopes.put(scopeName, scope);
+				}
+			}
+		}
+
+		public void restore() {
+			for (Map.Entry<String, Scope> entry : this.scopes.entrySet()) {
+				if (logger.isInfoEnabled()) {
+					logger.info("Restoring user defined scope " + entry.getKey());
+				}
+				this.beanFactory.registerScope(entry.getKey(), entry.getValue());
+			}
+		}
+
+	}
+
 }

spring-boot/src/test/java/org/springframework/boot/context/embedded/EmbeddedWebApplicationContextTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2013 the original author or authors.
+ * Copyright 2012-2015 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.
@@ -37,7 +37,9 @@ import org.junit.rules.ExpectedException;
 import org.mockito.InOrder;
 import org.springframework.beans.MutablePropertyValues;
 import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.config.ConstructorArgumentValues;
+import org.springframework.beans.factory.config.Scope;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.context.ApplicationContextException;
 import org.springframework.context.ApplicationListener;
@@ -53,6 +55,7 @@ import org.springframework.web.filter.GenericFilterBean;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.nullValue;
+import static org.hamcrest.Matchers.sameInstance;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertThat;
@@ -408,6 +411,24 @@ public class EmbeddedWebApplicationContextTests {
 				equalTo(8080));
 	}
 
+	@Test
+	public void doesNotReplaceExistingScopes() throws Exception { // gh-2082
+		Scope scope = mock(Scope.class);
+		ConfigurableListableBeanFactory factory = this.context.getBeanFactory();
+		factory.registerScope(WebApplicationContext.SCOPE_REQUEST, scope);
+		factory.registerScope(WebApplicationContext.SCOPE_SESSION, scope);
+		factory.registerScope(WebApplicationContext.SCOPE_GLOBAL_SESSION, scope);
+		addEmbeddedServletContainerFactoryBean();
+		this.context.refresh();
+		assertThat(factory.getRegisteredScope(WebApplicationContext.SCOPE_REQUEST),
+				sameInstance(scope));
+		assertThat(factory.getRegisteredScope(WebApplicationContext.SCOPE_SESSION),
+				sameInstance(scope));
+		assertThat(
+				factory.getRegisteredScope(WebApplicationContext.SCOPE_GLOBAL_SESSION),
+				sameInstance(scope));
+	}
+
 	private void addEmbeddedServletContainerFactoryBean() {
 		this.context.registerBeanDefinition("embeddedServletContainerFactory",
 				new RootBeanDefinition(MockEmbeddedServletContainerFactory.class));