Allow common messages to be specified for message sources

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

@@ -16,10 +16,16 @@
 
 package org.springframework.boot.autoconfigure.context;
 
+import java.io.IOException;
+import java.io.UncheckedIOException;
 import java.time.Duration;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
 
 import org.springframework.aot.hint.RuntimeHints;
 import org.springframework.aot.hint.RuntimeHintsRegistrar;
+import org.springframework.beans.factory.config.PropertiesFactoryBean;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
 import org.springframework.boot.autoconfigure.AutoConfigureOrder;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
@@ -39,7 +45,9 @@
 import org.springframework.context.support.AbstractApplicationContext;
 import org.springframework.context.support.ResourceBundleMessageSource;
 import org.springframework.core.Ordered;
+import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.core.io.Resource;
+import org.springframework.core.io.ResourceLoader;
 import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
 import org.springframework.core.type.AnnotatedTypeMetadata;
 import org.springframework.util.ConcurrentReferenceHashMap;
@@ -81,6 +89,25 @@ public MessageSource messageSource(MessageSourceProperties properties) {
 		}
 		messageSource.setAlwaysUseMessageFormat(properties.isAlwaysUseMessageFormat());
 		messageSource.setUseCodeAsDefaultMessage(properties.isUseCodeAsDefaultMessage());
+
+		try {
+			if (StringUtils.hasText(properties.getCommonMessages())) {
+				PropertiesFactoryBean propertiesFactory = new PropertiesFactoryBean();
+				ResourceLoader resourceLoader = new DefaultResourceLoader();
+				String[] commonMessages = StringUtils.commaDelimitedListToStringArray(
+						StringUtils.trimAllWhitespace(properties.getCommonMessages()));
+				List<Resource> commonResources = Arrays.stream(commonMessages)
+						.map(resourceLoader::getResource)
+						.toList();
+				propertiesFactory.setLocations(commonResources.toArray(Resource[]::new));
+				propertiesFactory.setSingleton(true);
+				propertiesFactory.setIgnoreResourceNotFound(true);
+				propertiesFactory.afterPropertiesSet();
+				messageSource.setCommonMessages(propertiesFactory.getObject());
+			}
+		} catch (IOException e) {
+			throw new UncheckedIOException("Failed to load common messages", e);
+		}
 		return messageSource;
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/context/MessageSourceProperties.java

@@ -42,6 +42,11 @@ public class MessageSourceProperties {
 	 */
 	private String basename = "messages";
 
+	/**
+	 * Comma-separated list of locale-independent common messages.
+	 */
+	private String commonMessages;
+
 	/**
 	 * Message bundles encoding.
 	 */
@@ -121,4 +126,11 @@ public void setUseCodeAsDefaultMessage(boolean useCodeAsDefaultMessage) {
 		this.useCodeAsDefaultMessage = useCodeAsDefaultMessage;
 	}
 
+	public String getCommonMessages() {
+		return this.commonMessages;
+	}
+
+	public void setCommonMessages(String commonMessages) {
+		this.commonMessages = commonMessages;
+	}
 }

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

@@ -116,6 +116,12 @@ void testMessageSourceFromPropertySourceAnnotation() {
 			.run((context) -> assertThat(context.getMessage("foo", null, "Foo message", Locale.UK)).isEqualTo("bar"));
 	}
 
+	@Test
+	void testCommonMessages() {
+		this.contextRunner.withPropertyValues("spring.messages.basename:test/messages", "spring.messages.common-messages:test/common-messages")
+			.run((context) -> assertThat(context.getMessage("hello", null, "Hello!", Locale.UK)).isEqualTo("world"));
+	}
+
 	@Test
 	void testFallbackDefault() {
 		this.contextRunner.withPropertyValues("spring.messages.basename:test/messages")

spring-boot-project/spring-boot-autoconfigure/src/test/resources/test/common-messages.properties

@@ -0,0 +1 @@
+hello=world