Small fix for non-existing openapi additional folder

extensions/smallrye-openapi/deployment/src/main/java/io/quarkus/smallrye/openapi/deployment/SmallRyeOpenApiProcessor.java

@@ -171,7 +171,8 @@ void configFiles(BuildProducer<HotDeploymentWatchedFileBuildItem> watchedFiles,
             List<Path> additionalStaticDocuments = openApiConfig.additionalDocsDirectory.get();
             for (Path path : additionalStaticDocuments) {
                 // Scan all yaml and json files
-                List<String> filesInDir = getResourceFiles(path.toString(), outputTargetBuildItem.getOutputDirectory());
+                List<String> filesInDir = getResourceFiles(PathUtils.asString(path, "/"),
+                        outputTargetBuildItem.getOutputDirectory());
                 for (String possibleFile : filesInDir) {
                     watchedFiles.produce(new HotDeploymentWatchedFileBuildItem(possibleFile));
                 }
@@ -845,10 +846,11 @@ private List<String> getResourceFiles(String pathName, Path target) throws IOExc
             Path classes = target.resolve("classes");
             if (classes != null) {
                 Path path = classes.resolve(pathName);
-
-                return Files.list(path).map((t) -> {
-                    return pathName + "/" + t.getFileName().toString();
-                }).collect(Collectors.toList());
+                if (Files.exists(path)) {
+                    return Files.list(path).map((t) -> {
+                        return pathName + "/" + t.getFileName().toString();
+                    }).collect(Collectors.toList());
+                }
             }
         }
         return filenames;

extensions/smallrye-openapi/deployment/src/test/java/io/quarkus/smallrye/openapi/test/jaxrs/OpenApiEmptyStaticModelsTestCase.java

@@ -0,0 +1,34 @@
+package io.quarkus.smallrye.openapi.test.jaxrs;
+
+import java.io.IOException;
+
+import org.hamcrest.Matchers;
+import org.jboss.shrinkwrap.api.asset.StringAsset;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.test.QuarkusUnitTest;
+import io.restassured.RestAssured;
+
+public class OpenApiEmptyStaticModelsTestCase {
+
+    private static String directory = "META-INF/foldernamethatdoesnotexist";
+
+    @RegisterExtension
+    static QuarkusUnitTest runner = new QuarkusUnitTest()
+            .withApplicationRoot((jar) -> jar
+                    .addClasses(OpenApiResource.class, ResourceBean.class)
+                    .addAsResource(
+                            new StringAsset("quarkus.smallrye-openapi.additional-docs-directory=" + directory),
+                            "application.properties"));
+
+    @Test
+    public void testNonExistingAdditionalDocsDirectory() throws IOException {
+
+        RestAssured.given().header("Accept", "application/json")
+                .when().get("/q/openapi")
+                .then()
+                .log().body().and()
+                .body("openapi", Matchers.startsWith("3.0."));
+    }
+}