Qute: fix generation of qute-i18n-examples

- handle localized enums correctly
- fixes quarkusio#44366

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

@@ -18,15 +18,17 @@ public final class MessageBundleMethodBuildItem extends MultiBuildItem {
     private final MethodInfo method;
     private final String template;
     private final boolean isDefaultBundle;
+    private final boolean hasGeneratedTemplate;
 
     MessageBundleMethodBuildItem(String bundleName, String key, String templateId, MethodInfo method, String template,
-            boolean isDefaultBundle) {
+            boolean isDefaultBundle, boolean hasGeneratedTemplate) {
         this.bundleName = bundleName;
         this.key = key;
         this.templateId = templateId;
         this.method = method;
         this.template = template;
         this.isDefaultBundle = isDefaultBundle;
+        this.hasGeneratedTemplate = hasGeneratedTemplate;
     }
 
     public String getBundleName() {
@@ -54,6 +56,11 @@ public MethodInfo getMethod() {
         return method;
     }
 
+    /**
+     *
+     * @return {@code true} if there is a corresponding method declared on the message bundle interface
+     * @see #getMethod()
+     */
     public boolean hasMethod() {
         return method != null;
     }
@@ -79,6 +86,14 @@ public boolean isDefaultBundle() {
         return isDefaultBundle;
     }
 
+    /**
+     *
+     * @return {@code true} if the template was generated, e.g. a message bundle method for an enum
+     */
+    public boolean hasGeneratedTemplate() {
+        return hasGeneratedTemplate;
+    }
+
     /**
      *
      * @return the path

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

@@ -702,8 +702,22 @@ void generateExamplePropertiesFiles(List<MessageBundleMethodBuildItem> messageBu
             List<MessageBundleMethodBuildItem> messages = entry.getValue();
             messages.sort(Comparator.comparing(MessageBundleMethodBuildItem::getKey));
             Path exampleProperties = generatedExamplesDir.resolve(entry.getKey() + ".properties");
-            Files.write(exampleProperties,
-                    messages.stream().map(m -> m.getMethod().name() + "=" + m.getTemplate()).collect(Collectors.toList()));
+            List<String> lines = new ArrayList<>();
+            for (MessageBundleMethodBuildItem m : messages) {
+                if (m.hasMethod()) {
+                    if (m.hasGeneratedTemplate()) {
+                        // Skip messages with generated templates
+                        continue;
+                    }
+                    // Keys are mapped to method names
+                    lines.add(m.getMethod().name() + "=" + m.getTemplate());
+                } else {
+                    // No corresponding method declared - use the key instead
+                    // For example, there is no method for generated enum constant message keys
+                    lines.add(m.getKey() + "=" + m.getTemplate());
+                }
+            }
+            Files.write(exampleProperties, lines);
         }
     }
 
@@ -992,6 +1006,7 @@ private String generateImplementation(MessageBundleBuildItem bundle, ClassInfo d
             }
             keyMap.put(key, new SimpleMessageMethod(method));
 
+            boolean generatedTemplate = false;
             String messageTemplate = messageTemplates.get(method.name());
             if (messageTemplate == null) {
                 messageTemplate = getMessageAnnotationValue(messageAnnotation);
@@ -1043,6 +1058,7 @@ private String generateImplementation(MessageBundleBuildItem bundle, ClassInfo d
                         }
                         generatedMessageTemplate.append("{/when}");
                         messageTemplate = generatedMessageTemplate.toString();
+                        generatedTemplate = true;
                     }
                 }
             }
@@ -1068,7 +1084,7 @@ private String generateImplementation(MessageBundleBuildItem bundle, ClassInfo d
             }
 
             MessageBundleMethodBuildItem messageBundleMethod = new MessageBundleMethodBuildItem(bundleName, key, templateId,
-                    method, messageTemplate, defaultBundleInterface == null);
+                    method, messageTemplate, defaultBundleInterface == null, generatedTemplate);
             messageTemplateMethods
                     .produce(messageBundleMethod);
 
@@ -1139,8 +1155,7 @@ private void generateEnumConstantMessageMethod(ClassCreator bundleCreator, Strin
         }
 
         MessageBundleMethodBuildItem messageBundleMethod = new MessageBundleMethodBuildItem(bundleName, enumConstantKey,
-                templateId, null, messageTemplate,
-                defaultBundleInterface == null);
+                templateId, null, messageTemplate, defaultBundleInterface == null, true);
         messageTemplateMethods.produce(messageBundleMethod);
 
         MethodCreator enumConstantMethod = bundleCreator.getMethodCreator(enumConstantKey,

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

@@ -0,0 +1,64 @@
+package io.quarkus.qute.deployment.i18n;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.Properties;
+
+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.Message;
+import io.quarkus.qute.i18n.MessageBundle;
+import io.quarkus.test.ProdBuildResults;
+import io.quarkus.test.ProdModeTestResults;
+import io.quarkus.test.QuarkusProdModeTest;
+
+public class MessageBundleEnumExampleFileTest {
+
+    @RegisterExtension
+    static final QuarkusProdModeTest config = new QuarkusProdModeTest()
+            .withApplicationRoot(root -> root
+                    .addClasses(Messages.class, MyEnum.class)
+                    .addAsResource(new StringAsset("""
+                            myEnum_ON=On
+                            myEnum_OFF=Off
+                            myEnum_UNDEFINED=Undefined
+                            """),
+                            "messages/enu.properties"));
+
+    @ProdBuildResults
+    ProdModeTestResults testResults;
+
+    @Test
+    public void testExampleProperties() throws FileNotFoundException, IOException {
+        Path path = testResults.getBuildDir().resolve("qute-i18n-examples").resolve("enu.properties");
+        assertTrue(path.toFile().canRead());
+        Properties props = new Properties();
+        props.load(new FileInputStream(path.toFile()));
+        assertEquals(3, props.size());
+        assertTrue(props.containsKey("myEnum_ON"));
+        assertTrue(props.containsKey("myEnum_OFF"));
+        assertTrue(props.containsKey("myEnum_UNDEFINED"));
+    }
+
+    @MessageBundle(value = "enu", locale = "en")
+    public interface Messages {
+
+        // Replaced with:
+        // @Message("{#when myEnum}"
+        //  + "{#is ON}{enu:myEnum_ON}"
+        //  + "{#is OFF}{enu:myEnum_OFF}"
+        //  + "{#is UNDEFINED}{enu:myEnum_UNDEFINED}"
+        //  + "{/when}")
+        @Message
+        String myEnum(MyEnum myEnum);
+
+    }
+
+}

extensions/qute/runtime/src/main/java/io/quarkus/qute/i18n/Message.java

@@ -27,8 +27,7 @@
  * There is a convenient way to localize enums.
  * <p>
  * If there is a message bundle method that accepts a single parameter of an enum type and has no message template defined then
- * it
- * receives a generated template:
+ * it receives a generated template:
  *
  * <pre>
  * {#when enumParamName}