Ignore parent contexts in message source auto-configuration

This commit applies the changes made in 68b55ad to 1.2.x (it was
originally only made in 1.0.x and master). It also adds some tests.

Closes spring-projectsgh-3803

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/MessageSourceAutoConfiguration.java

@@ -23,6 +23,7 @@
 import org.springframework.boot.autoconfigure.MessageSourceAutoConfiguration.ResourceBundleCondition;
 import org.springframework.boot.autoconfigure.condition.ConditionOutcome;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.SearchStrategy;
 import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
@@ -50,7 +51,7 @@
  * @author Phillip Webb
  */
 @Configuration
-@ConditionalOnMissingBean(MessageSource.class)
+@ConditionalOnMissingBean(value = MessageSource.class, search = SearchStrategy.CURRENT)
 @Order(Ordered.HIGHEST_PRECEDENCE)
 @Conditional(ResourceBundleCondition.class)
 @EnableConfigurationProperties

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/MessageSourceAutoConfigurationTests.java

@@ -21,7 +21,12 @@
 import org.junit.Ignore;
 import org.junit.Test;
 import org.springframework.boot.test.EnvironmentTestUtils;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.MessageSource;
+import org.springframework.context.MessageSourceResolvable;
+import org.springframework.context.NoSuchMessageException;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.PropertySource;
 
@@ -107,9 +112,69 @@ public void testMessageSourceFromPropertySourceAnnotation() throws Exception {
 				this.context.getMessage("foo", null, "Foo message", Locale.UK));
 	}
 
+	@Test
+	public void existingMessageSourceIsPreferred() {
+		this.context = new AnnotationConfigApplicationContext();
+		this.context.register(CustomMessageSource.class,
+				MessageSourceAutoConfiguration.class,
+				PropertyPlaceholderAutoConfiguration.class);
+		this.context.refresh();
+		assertEquals("foo", this.context.getMessage("foo", null, null, null));
+	}
+
+	@Test
+	public void existingMessageSourceInParentIsIgnored() {
+		ConfigurableApplicationContext parent = new AnnotationConfigApplicationContext();
+		parent.refresh();
+		try {
+			this.context = new AnnotationConfigApplicationContext();
+			this.context.setParent(parent);
+			EnvironmentTestUtils.addEnvironment(this.context,
+					"spring.messages.basename:test/messages");
+			this.context.register(MessageSourceAutoConfiguration.class,
+					PropertyPlaceholderAutoConfiguration.class);
+			this.context.refresh();
+			assertEquals("bar",
+					this.context.getMessage("foo", null, "Foo message", Locale.UK));
+		}
+		finally {
+			parent.close();
+		}
+	}
+
 	@Configuration
 	@PropertySource("classpath:/switch-messages.properties")
 	protected static class Config {
 
 	}
+
+	@Configuration
+	protected static class CustomMessageSource {
+
+		@Bean
+		public MessageSource messageSource() {
+			return new MessageSource() {
+
+				@Override
+				public String getMessage(String code, Object[] args,
+						String defaultMessage, Locale locale) {
+					return code;
+				}
+
+				@Override
+				public String getMessage(String code, Object[] args, Locale locale)
+						throws NoSuchMessageException {
+					return code;
+				}
+
+				@Override
+				public String getMessage(MessageSourceResolvable resolvable,
+						Locale locale) throws NoSuchMessageException {
+					return resolvable.getCodes()[0];
+				}
+
+			};
+		}
+
+	}
 }