Qute: Allow to specify default bundle file without language tag

docs/src/main/asciidoc/qute-reference.adoc

@@ -2596,6 +2596,9 @@ public interface GermanAppMessages extends AppMessages {
 
 Message bundle files must be encoded in _UTF-8_.
 The file name consists of the relevant bundle name (e.g. `msg`) and underscore followed by a language tag (IETF; e.g. `en-US`).
+The language tag may be omitted, in which case the language tag of the default bundle locale is used.
+For example, if bundle `msg` has default locale `en`, then `msg.properties` is going to be treated as `msg_en.properties`.
+If both `msg.properties` and `msg_en.properties` are detected, an exception is thrown and build fails.
 The file format is very simple: each line represents either a key/value pair with the equals sign used as a separator or a comment (line starts with `#`).
 Blank lines are ignored.
 Keys are _mapped to method names_ from the corresponding message bundle interface.

extensions/qute/deployment/src/main/java/io/quarkus/qute/deployment/MessageBundleProcessor.java

@@ -206,13 +206,24 @@ List<MessageBundleBuildItem> processBundles(BeanArchiveIndexBuildItem beanArchiv
                     for (Path messageFile : messageFiles) {
                         String fileName = messageFile.getFileName().toString();
                         if (fileName.startsWith(name)) {
-                            // msg_en.txt -> en
-                            // msg_Views_Index_cs.properties -> cs
-                            // msg_Views_Index_cs-CZ.properties -> cs-CZ
-                            // msg_Views_Index_cs_CZ.properties -> cs_CZ
-                            String locale = fileName.substring(name.length() + 1, fileName.indexOf('.'));
-                            // Support resource bundle naming convention
-                            locale = locale.replace('_', '-');
+                            final String locale;
+                            int postfixIdx = fileName.indexOf('.');
+                            if (postfixIdx == name.length()) {
+
+                                // msg.txt -> use bundle default locale
+                                locale = defaultLocale;
+                            } else {
+
+                                locale = fileName
+                                        // msg_en.txt -> en
+                                        // msg_Views_Index_cs.properties -> cs
+                                        // msg_Views_Index_cs-CZ.properties -> cs-CZ
+                                        // msg_Views_Index_cs_CZ.properties -> cs_CZ
+                                        .substring(name.length() + 1, postfixIdx)
+                                        // Support resource bundle naming convention
+                                        .replace('_', '-');
+                            }
+
                             ClassInfo localizedInterface = localeToInterface.get(locale);
                             if (defaultLocale.equals(locale) || localizedInterface != null) {
                                 // both file and interface exist for one locale, therefore we need to merge them

extensions/qute/deployment/src/test/java/io/quarkus/qute/deployment/i18n/DefaultFileBundleLocaleMergeTest.java

@@ -0,0 +1,111 @@
+package io.quarkus.qute.deployment.i18n;
+
+import static io.quarkus.qute.i18n.MessageBundle.DEFAULT_NAME;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import jakarta.inject.Inject;
+
+import org.jboss.shrinkwrap.api.asset.StringAsset;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.qute.i18n.Localized;
+import io.quarkus.qute.i18n.Message;
+import io.quarkus.qute.i18n.MessageBundle;
+import io.quarkus.test.QuarkusUnitTest;
+
+public class DefaultFileBundleLocaleMergeTest {
+
+    @RegisterExtension
+    static final QuarkusUnitTest config = new QuarkusUnitTest()
+            .withApplicationRoot((jar) -> jar
+                    .addClasses(Messages.class, EnMessages.class, DeMessages.class)
+                    .addAsResource(new StringAsset("hello_world=Hi!"), "messages/msg_en.properties")
+                    .addAsResource(new StringAsset("farewell=Abschied\ngoodbye=Freilos"), "messages/msg_de.properties")
+                    .addAsResource(new StringAsset("goodbye=Mej se!\nfarewell=Sbohem!\nhello_world=Zdravim svete!"),
+                            "messages/msg.properties"))
+            .overrideConfigKey("quarkus.default-locale", "cs");
+
+    @Localized("en")
+    Messages enMessages;
+
+    @Localized("de")
+    Messages deMessages;
+
+    @Inject
+    Messages csMessages;
+
+    /**
+     * Default message template method is not overridden and message was set with {@link Message#value()}.
+     */
+    @Test
+    void testDefaultFromAnnotationIsUsedAsFallback() {
+        assertEquals("Nazdar!", enMessages.hello());
+    }
+
+    /**
+     * Default message template method is not overridden and message was set in default 'msg.properties' file.
+     */
+    @Test
+    void testDefaultFromFileIsUsedAsFallback() {
+        assertEquals("Mej se!", enMessages.goodbye());
+    }
+
+    /**
+     * Localized message template method is provided without {@link Message#value()}
+     */
+    @Test
+    void testDefaultIsUsedAsFallback2() {
+        assertEquals("Greetings!", enMessages.greetings());
+    }
+
+    @Test
+    void testLocalizedFileIsMerged() {
+        assertEquals("Freilos", deMessages.goodbye());
+    }
+
+    /**
+     * Default message set with {@link Message#value()} has priority over message from 'msg.properties'.
+     */
+    @Test
+    void testDefaultInterfaceHasPriority() {
+        assertEquals("Ahoj svete!", csMessages.hello_world());
+    }
+
+    @Test
+    void testBothDefaultAndLocalizedFromFile() {
+        assertEquals("Abschied", deMessages.farewell());
+    }
+
+    @MessageBundle(DEFAULT_NAME)
+    public interface Messages {
+
+        @Message("Ahoj svete!")
+        String hello_world();
+
+        @Message("Nazdar!")
+        String hello();
+
+        String goodbye();
+
+        @Message("Greetings!")
+        String greetings();
+
+        @Message
+        String farewell();
+    }
+
+    @Localized("en")
+    public interface EnMessages extends Messages {
+
+        @Message
+        String greetings();
+
+    }
+
+    @Localized("de")
+    public interface DeMessages extends Messages {
+
+    }
+
+}

extensions/qute/deployment/src/test/java/io/quarkus/qute/deployment/i18n/DefaultFileDefaultBundleNameTest.java

@@ -0,0 +1,51 @@
+package io.quarkus.qute.deployment.i18n;
+
+import static io.quarkus.qute.i18n.MessageBundle.DEFAULT_NAME;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import jakarta.inject.Inject;
+
+import org.jboss.shrinkwrap.api.asset.StringAsset;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.qute.i18n.Localized;
+import io.quarkus.qute.i18n.Message;
+import io.quarkus.qute.i18n.MessageBundle;
+import io.quarkus.test.QuarkusUnitTest;
+
+public class DefaultFileDefaultBundleNameTest {
+
+    @RegisterExtension
+    static final QuarkusUnitTest config = new QuarkusUnitTest()
+            .withApplicationRoot((jar) -> jar
+                    .addClasses(Messages.class)
+                    .addAsResource(new StringAsset("goodbye=Mej se!\nfarewell=Sbohem!"), "messages/msg.properties"))
+            .overrideConfigKey("quarkus.default-locale", "cs");
+
+    @Inject
+    Messages csMessages1;
+
+    @Localized("cs")
+    Messages csMessages2;
+
+    @Test
+    void unannotatedMessageMethod() {
+        assertEquals("Mej se!", csMessages1.goodbye());
+    }
+
+    @Test
+    void annotatedMessageMethod() {
+        assertEquals("Sbohem!", csMessages2.farewell());
+    }
+
+    @MessageBundle(DEFAULT_NAME)
+    public interface Messages {
+
+        String goodbye();
+
+        @Message
+        String farewell();
+    }
+
+}

extensions/qute/deployment/src/test/java/io/quarkus/qute/deployment/i18n/DefaultFileDuplicateFoundTest.java

@@ -0,0 +1,52 @@
+package io.quarkus.qute.deployment.i18n;
+
+import static io.quarkus.qute.i18n.MessageBundle.DEFAULT_NAME;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
+
+import org.jboss.shrinkwrap.api.asset.StringAsset;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.qute.deployment.MessageBundleException;
+import io.quarkus.qute.i18n.Message;
+import io.quarkus.qute.i18n.MessageBundle;
+import io.quarkus.test.QuarkusUnitTest;
+
+public class DefaultFileDuplicateFoundTest {
+
+    @RegisterExtension
+    static final QuarkusUnitTest config = new QuarkusUnitTest()
+            .withApplicationRoot(root -> root
+                    .addAsResource(new StringAsset("hi=Nazdar!"), "messages/msg.properties")
+                    .addAsResource(new StringAsset("hi=Ahoj!"), "messages/msg_cs.properties"))
+            .overrideConfigKey("quarkus.default-locale", "cs")
+            .assertException(t -> {
+                Throwable e = t;
+                MessageBundleException mbe = null;
+                while (e != null) {
+                    if (e instanceof MessageBundleException) {
+                        mbe = (MessageBundleException) e;
+                        break;
+                    }
+                    e = e.getCause();
+                }
+                assertNotNull(mbe);
+                assertTrue(mbe.getMessage().contains("localized file already exists for locale [cs]"), mbe.getMessage());
+                assertTrue(mbe.getMessage().contains("msg_cs.properties"), mbe.getMessage());
+                assertTrue(mbe.getMessage().contains("msg.properties"), mbe.getMessage());
+            });
+
+    @Test
+    public void testValidation() {
+        fail();
+    }
+
+    @MessageBundle(DEFAULT_NAME)
+    public interface Messages {
+        @Message
+        String hi();
+    }
+
+}