fix: register RouteUnifyingIndexHtmlRequestListener only when React is enabled

packages/java/endpoint/src/main/java/com/vaadin/hilla/route/ClientRouteRegistry.java

@@ -28,6 +28,7 @@
 import java.io.Serializable;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.nio.file.Paths;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.Set;
@@ -116,30 +117,43 @@ public ClientViewConfig getRouteByPath(String path) {
      */
     public void registerClientRoutes(
             DeploymentConfiguration deploymentConfiguration) {
-        try (var source = getViewsJsonAsResource(deploymentConfiguration)
-                .openStream()) {
+        var viewsJsonAsResource = getViewsJsonAsResource(
+                deploymentConfiguration);
+        if (viewsJsonAsResource == null || !Paths
+                .get(viewsJsonAsResource.getPath()).toFile().exists()) {
+            LOGGER.debug(
+                    "No 'views.json' found either in the frontend/generated "
+                            + "folder or in the META-INF/VAADIN folder. Skipping client "
+                            + "route registration.");
+            return;
+        }
+        try (var source = viewsJsonAsResource.openStream()) {
             if (source != null) {
                 clearRoutes();
                 registerAndRecurseChildren("",
                         mapper.readValue(source, new TypeReference<>() {
                         }));
-            } else {
-                LOGGER.warn("Failed to find views.json");
             }
         } catch (IOException e) {
-            LOGGER.warn("Failed extract client views from views.json", e);
+            LOGGER.warn("Failed load client views from {}",
+                    viewsJsonAsResource.getPath(), e);
         }
     }
 
     private URL getViewsJsonAsResource(
-            DeploymentConfiguration deploymentConfiguration)
-            throws MalformedURLException {
+            DeploymentConfiguration deploymentConfiguration) {
         var isProductionMode = deploymentConfiguration.isProductionMode();
         if (isProductionMode) {
             return getClass().getResource("/META-INF/VAADIN/views.json");
         }
-        return deploymentConfiguration.getFrontendFolder().toPath()
-                .resolve("generated").resolve("views.json").toUri().toURL();
+        try {
+            return deploymentConfiguration.getFrontendFolder().toPath()
+                    .resolve("generated").resolve("views.json").toUri().toURL();
+        } catch (MalformedURLException e) {
+            LOGGER.warn("Failed to find views.json under frontend/generated",
+                    e);
+            throw new RuntimeException(e);
+        }
     }
 
     private void registerAndRecurseChildren(String basePath,

packages/java/endpoint/src/main/java/com/vaadin/hilla/startup/RouteUnifyingServiceInitListener.java

@@ -54,15 +54,17 @@ public RouteUnifyingServiceInitListener(
     public void serviceInit(ServiceInitEvent event) {
         var deploymentConfiguration = event.getSource()
                 .getDeploymentConfiguration();
-        var routeExtractionIndexHtmlRequestListener = new RouteUnifyingIndexHtmlRequestListener(
-                clientRouteRegistry, deploymentConfiguration);
-        var deploymentMode = deploymentConfiguration.isProductionMode()
-                ? "PRODUCTION"
-                : "DEVELOPMENT";
-        event.addIndexHtmlRequestListener(
-                routeExtractionIndexHtmlRequestListener);
-        LOGGER.debug(
-                "{} mode: Registered RouteUnifyingIndexHtmlRequestListener.",
-                deploymentMode);
+        if (deploymentConfiguration.isReactEnabled()) {
+            var routeUnifyingIndexHtmlRequestListener = new RouteUnifyingIndexHtmlRequestListener(
+                    clientRouteRegistry, deploymentConfiguration);
+            var deploymentMode = deploymentConfiguration.isProductionMode()
+                    ? "PRODUCTION"
+                    : "DEVELOPMENT";
+            event.addIndexHtmlRequestListener(
+                    routeUnifyingIndexHtmlRequestListener);
+            LOGGER.debug(
+                    "{} mode: Registered RouteUnifyingIndexHtmlRequestListener.",
+                    deploymentMode);
+        }
     }
 }

packages/java/endpoint/src/test/java/com/vaadin/hilla/startup/RouteUnifyingServiceInitListenerTest.java

@@ -41,16 +41,30 @@ public void setup() throws IOException {
     }
 
     @Test
-    public void should_addRouteIndexHtmlRequestListener() {
-        Assert.assertFalse("Unexpected RouteIndexHtmlRequestListener added",
-                eventHasAddedRouteIndexHtmlRequestListener(event));
+    public void should_addRouteIndexHtmlRequestListener_when_react_is_enabled() {
+        Mockito.when(mockDeploymentConfiguration.isReactEnabled())
+                .thenReturn(true);
+
+        Assert.assertFalse("Unexpected RouteUnifyingServiceInitListener added",
+                hasRouteUnifyingIndexHtmlRequestListenerAdded(event));
         routeUnifyingServiceInitListener.serviceInit(event);
         Assert.assertTrue(
-                "Expected event to have RouteIndexHtmlRequestListener added",
-                eventHasAddedRouteIndexHtmlRequestListener(event));
+                "Expected to have RouteUnifyingServiceInitListener added",
+                hasRouteUnifyingIndexHtmlRequestListenerAdded(event));
+    }
+
+    @Test
+    public void should_not_addRouteIndexHtmlRequestListener_when_react_is_not_enabled() {
+        Mockito.when(mockDeploymentConfiguration.isReactEnabled())
+                .thenReturn(false);
+
+        routeUnifyingServiceInitListener.serviceInit(event);
+        Assert.assertFalse(
+                "RouteIndexHtmlRequestListener added unexpectedly when React is not enabled",
+                hasRouteUnifyingIndexHtmlRequestListenerAdded(event));
     }
 
-    private boolean eventHasAddedRouteIndexHtmlRequestListener(
+    private boolean hasRouteUnifyingIndexHtmlRequestListenerAdded(
             ServiceInitEvent event) {
         return event.getAddedIndexHtmlRequestListeners().anyMatch(
                 indexHtmlRequestListener -> indexHtmlRequestListener instanceof RouteUnifyingIndexHtmlRequestListener);