Fix NullPointerException when using multipart with optional value

extensions/resteasy-reactive/quarkus-resteasy-reactive/deployment/src/test/java/io/quarkus/resteasy/reactive/server/test/multipart/MultipartOptionalInputTest.java

@@ -0,0 +1,78 @@
+package io.quarkus.resteasy.reactive.server.test.multipart;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+
+import java.io.File;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.function.Supplier;
+
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.asset.StringAsset;
+import org.jboss.shrinkwrap.api.spec.JavaArchive;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.resteasy.reactive.server.test.multipart.other.OtherPackageFormDataBase;
+import io.quarkus.test.QuarkusUnitTest;
+import io.restassured.RestAssured;
+
+public class MultipartOptionalInputTest extends AbstractMultipartTest {
+
+    private static final Path uploadDir = Paths.get("file-uploads");
+
+    @RegisterExtension
+    static QuarkusUnitTest test = new QuarkusUnitTest()
+            .setArchiveProducer(new Supplier<JavaArchive>() {
+                @Override
+                public JavaArchive get() {
+                    return ShrinkWrap.create(JavaArchive.class)
+                            .addClasses(FormDataBase.class, OtherPackageFormDataBase.class, FormData.class, Status.class,
+                                    OtherFormData.class, FormDataSameFileName.class,
+                                    OtherFormDataBase.class,
+                                    MultipartResource.class, OtherMultipartResource.class)
+                            .addAsResource(new StringAsset(
+                                    // keep the files around so we can assert the outcome
+                                    "quarkus.http.body.delete-uploaded-files-on-end=false\nquarkus.http.body.uploads-directory="
+                                            + uploadDir.toString() + "\n"),
+                                    "application.properties");
+                }
+
+            });
+
+    private final File HTML_FILE = new File("./src/test/resources/test.html");
+
+    @BeforeEach
+    public void assertEmptyUploads() {
+        Assertions.assertTrue(isDirectoryEmpty(uploadDir));
+    }
+
+    @AfterEach
+    public void clearDirectory() {
+        clearDirectory(uploadDir);
+    }
+
+    @Test
+    public void testUploadWithSomeFilesMissing() {
+        RestAssured.given()
+                .multiPart("name", "Alice")
+                .multiPart("active", "true")
+                .multiPart("num", "25")
+                .multiPart("status", "WORKING")
+                .multiPart("htmlFile", HTML_FILE, "text/html")
+                .accept("text/plain")
+                .when()
+                .post("/multipart/optional")
+                .then()
+                .statusCode(200)
+                .body(equalTo("Alice - true - 50 - WORKING - true - false - false"));
+
+        // ensure that the 1 uploaded file was created on disk
+        File[] uploadedFiles = uploadDir.toFile().listFiles();
+        Assertions.assertNotNull(uploadedFiles);
+        Assertions.assertEquals(1, uploadedFiles.length);
+    }
+}

extensions/resteasy-reactive/quarkus-resteasy-reactive/deployment/src/test/java/io/quarkus/resteasy/reactive/server/test/multipart/MultipartResource.java

@@ -67,4 +67,18 @@ public String sameName(FormDataSameFileName formData) {
                 + formData.xmlFiles.size();
     }
 
+    @POST
+    @Produces(MediaType.TEXT_PLAIN)
+    @Consumes(MediaType.MULTIPART_FORM_DATA)
+    @Path("/optional")
+    @NonBlocking
+    public String optional(@MultipartForm FormData formData) {
+        if (BlockingOperationControl.isBlockingAllowed()) {
+            throw new RuntimeException("should not have dispatched");
+        }
+        return formData.getName() + " - " + formData.active + " - " + formData.getNum() + " - " + formData.getStatus()
+                + " - " + (formData.getHtmlPart() != null) + " - " + (formData.xmlPart != null) + " - "
+                + (formData.txtFile != null);
+    }
+
 }

extensions/resteasy-reactive/quarkus-resteasy-reactive/runtime/src/main/java/io/quarkus/resteasy/reactive/server/runtime/multipart/MultipartSupport.java

@@ -9,6 +9,7 @@
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 
@@ -23,6 +24,7 @@
 import org.jboss.resteasy.reactive.server.core.ServerSerialisers;
 import org.jboss.resteasy.reactive.server.core.multipart.DefaultFileUpload;
 import org.jboss.resteasy.reactive.server.core.multipart.FormData;
+import org.jboss.resteasy.reactive.server.core.multipart.FormData.FormValue;
 import org.jboss.resteasy.reactive.server.handlers.RequestDeserializeHandler;
 import org.jboss.resteasy.reactive.server.spi.ServerMessageBodyReader;
 
@@ -98,9 +100,12 @@ public static List<DefaultFileUpload> getFileUploads(String formName, ResteasyRe
         List<DefaultFileUpload> result = new ArrayList<>();
         FormData fileUploads = context.getFormData();
         if (fileUploads != null) {
-            for (FormData.FormValue fileUpload : fileUploads.get(formName)) {
-                if (fileUpload.isFileItem()) {
-                    result.add(new DefaultFileUpload(formName, fileUpload));
+            Collection<FormValue> fileUploadsForName = fileUploads.get(formName);
+            if (fileUploadsForName != null) {
+                for (FormData.FormValue fileUpload : fileUploadsForName) {
+                    if (fileUpload.isFileItem()) {
+                        result.add(new DefaultFileUpload(formName, fileUpload));
+                    }
                 }
             }
         }