Fix native image generated static resources index

(cherry picked from commit 22a264d)

Author: ia3andy

extensions/vertx-http/deployment-spi/src/main/java/io/quarkus/vertx/http/deployment/spi/GeneratedStaticResourceBuildItem.java

@@ -18,7 +18,7 @@
  * {@link AdditionalStaticResourceBuildItem}, {@link NativeImageResourceBuildItem}
  * and {@link io.quarkus.deployment.builditem.GeneratedResourceBuildItem} build items.
  * <br>
- * The value of {@code endpoint} should be prefixed with {@code '/'}.
+ * The value of {@code endpoint} should be prefixed with {@code '/'} and reference a file (no trailing `/`).
  */
 public final class GeneratedStaticResourceBuildItem extends MultiBuildItem {
 
@@ -28,8 +28,14 @@ public final class GeneratedStaticResourceBuildItem extends MultiBuildItem {
     private final byte[] content;
 
     private GeneratedStaticResourceBuildItem(final String endpoint, final byte[] content, final Path file) {
-        if (!requireNonNull(endpoint, "endpoint is required").startsWith("/")) {
-            throw new IllegalArgumentException("endpoint must start with '/'");
+        requireNonNull(endpoint, "endpoint is required");
+        if (!endpoint.startsWith("/")) {
+            throw new IllegalArgumentException(
+                    "GeneratedStaticResourceBuildItem endpoint must start with '/': %s".formatted(endpoint));
+        }
+        if (endpoint.endsWith("/")) {
+            throw new IllegalArgumentException(
+                    "GeneratedStaticResourceBuildItem endpoint must not end with '/': %s".formatted(endpoint));
         }
         this.endpoint = endpoint;
         this.file = file;

extensions/vertx-http/deployment/src/main/java/io/quarkus/vertx/http/deployment/GeneratedStaticResourcesProcessor.java

@@ -73,6 +73,12 @@ public void produceResources(List<GeneratedStaticResourceBuildItem> generatedSta
                 additionalStaticResourcesProducer.produce(
                         new AdditionalStaticResourceBuildItem(generatedStaticResource.getEndpoint(), false));
                 nativeImageResourcesProducer.produce(new NativeImageResourceBuildItem(generatedStaticResourceLocation));
+                int lastSep = generatedStaticResourceLocation.lastIndexOf('/');
+                if (lastSep > 0) {
+                    String parent = generatedStaticResourceLocation.substring(0, lastSep);
+                    // if the resource is somehow an index page, we need the parent directory to also be added as a native resource so that we can resolve both `/path/index.html` and `/path/` (needed by Vert.x static handler).
+                    nativeImageResourcesProducer.produce(new NativeImageResourceBuildItem(parent));
+                }
             }
         }
     }