return explicit Response rather than Void from async controllers with no expected body content

service/src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java

@@ -274,9 +274,9 @@ public class AccountController {
   )
   @ApiResponse(responseCode = "204", description = "Username successfully deleted.", useReturnTypeSchema = true)
   @ApiResponse(responseCode = "401", description = "Account authentication check failed.")
-  public CompletableFuture<Void> deleteUsernameHash(@Auth final AuthenticatedAccount auth) {
+  public CompletableFuture<Response> deleteUsernameHash(@Auth final AuthenticatedAccount auth) {
     return accounts.clearUsernameHash(auth.getAccount())
-        .thenRun(Util.NOOP);
+        .thenApply(Util.ASYNC_EMPTY_RESPONSE);
   }
 
   @PUT
@@ -518,8 +518,8 @@ public class AccountController {
 
   @DELETE
   @Path("/me")
-  public CompletableFuture<Void> deleteAccount(@Auth DisabledPermittedAuthenticatedAccount auth) throws InterruptedException {
+  public CompletableFuture<Response> deleteAccount(@Auth DisabledPermittedAuthenticatedAccount auth) throws InterruptedException {
-    return accounts.delete(auth.getAccount(), AccountsManager.DeletionReason.USER_REQUEST);
+    return accounts.delete(auth.getAccount(), AccountsManager.DeletionReason.USER_REQUEST).thenApply(Util.ASYNC_EMPTY_RESPONSE);
   }
 
   private void clearUsernameLink(final Account account) {

service/src/main/java/org/whispersystems/textsecuregcm/controllers/KeysController.java

@@ -121,7 +121,7 @@ public class KeysController {
   @ApiResponse(responseCode = "401", description = "Account authentication check failed.")
   @ApiResponse(responseCode = "403", description = "Attempt to change identity key from a non-primary device.")
   @ApiResponse(responseCode = "422", description = "Invalid request format.")
-  public CompletableFuture<Void> setKeys(@Auth final DisabledPermittedAuthenticatedAccount disabledPermittedAuth,
+  public CompletableFuture<Response> setKeys(@Auth final DisabledPermittedAuthenticatedAccount disabledPermittedAuth,
       @RequestBody @NotNull @Valid final PreKeyState preKeys,
 
       @Parameter(allowEmptyValue=true)
@@ -189,7 +189,8 @@ public class KeysController {
     }
 
     return keys.store(getIdentifier(account, identityType), device.getId(),
-        preKeys.getPreKeys(), preKeys.getPqPreKeys(), preKeys.getSignedPreKey(), preKeys.getPqLastResortPreKey());
+        preKeys.getPreKeys(), preKeys.getPqPreKeys(), preKeys.getSignedPreKey(), preKeys.getPqLastResortPreKey())
+        .thenApply(Util.ASYNC_EMPTY_RESPONSE);
   }
 
   @GET
@@ -299,7 +300,7 @@ public class KeysController {
   @ApiResponse(responseCode = "200", description = "Indicates that new prekey was successfully stored.")
   @ApiResponse(responseCode = "401", description = "Account authentication check failed.")
   @ApiResponse(responseCode = "422", description = "Invalid request format.")
-  public CompletableFuture<Void> setSignedKey(@Auth final AuthenticatedAccount auth,
+  public CompletableFuture<Response> setSignedKey(@Auth final AuthenticatedAccount auth,
       @Valid final ECSignedPreKey signedPreKey,
       @QueryParam("identity") final Optional<String> identityType) {
 
@@ -314,7 +315,8 @@ public class KeysController {
     });
 
     return keys.storeEcSignedPreKeys(getIdentifier(auth.getAccount(), identityType),
-        Map.of(device.getId(), signedPreKey));
+        Map.of(device.getId(), signedPreKey))
+        .thenApply(Util.ASYNC_EMPTY_RESPONSE);
   }
 
   private static boolean usePhoneNumberIdentity(final Optional<String> identityType) {

service/src/main/java/org/whispersystems/textsecuregcm/controllers/MessageController.java

@@ -581,7 +581,7 @@ public class MessageController {
   @Timed
   @DELETE
   @Path("/uuid/{uuid}")
-  public CompletableFuture<Void> removePendingMessage(@Auth AuthenticatedAccount auth, @PathParam("uuid") UUID uuid) {
+  public CompletableFuture<Response> removePendingMessage(@Auth AuthenticatedAccount auth, @PathParam("uuid") UUID uuid) {
     return messagesManager.delete(
             auth.getAccount().getUuid(),
             auth.getAuthenticatedDevice().getId(),
@@ -603,7 +603,8 @@ public class MessageController {
               }
             }
           });
-        });
+        })
+        .thenApply(Util.ASYNC_EMPTY_RESPONSE);
   }
 
   @Timed

service/src/main/java/org/whispersystems/textsecuregcm/util/Util.java

@@ -16,8 +16,12 @@ import java.util.Locale;
 import java.util.Locale.LanguageRange;
 import java.util.Optional;
 import java.util.concurrent.TimeUnit;
+import java.util.function.Function;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+
+import javax.ws.rs.core.Response;
+
 import org.apache.commons.lang3.StringUtils;
 
 public class Util {
@@ -28,6 +32,12 @@ public class Util {
 
   public static final Runnable NOOP = () -> {};
 
+  // Use `CompletableFuture#thenApply(ASYNC_EMPTY_RESPONSE) to convert futures to
+  // CompletableFuture<Response> instead of using NOOP to convert them to CompletableFuture<Void>
+  // for jersey controllers; https://github.com/eclipse-ee4j/jersey/issues/3901 causes controllers
+  // returning Void futures to behave differently than synchronous controllers returning void
+  public static final Function<Object, Response> ASYNC_EMPTY_RESPONSE = ignored -> Response.noContent().build();
+
   /**
    * Checks that the given number is a valid, E164-normalized phone number.
    *

service/src/test/java/org/whispersystems/textsecuregcm/controllers/AccountControllerTest.java

@@ -38,6 +38,7 @@ import java.util.List;
 import java.util.Optional;
 import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
 import java.util.stream.Stream;
 import javax.ws.rs.client.Entity;
 import javax.ws.rs.client.Invocation;
@@ -90,6 +91,7 @@ import org.whispersystems.textsecuregcm.storage.UsernameHashNotAvailableExceptio
 import org.whispersystems.textsecuregcm.storage.UsernameReservationNotFoundException;
 import org.whispersystems.textsecuregcm.tests.util.AccountsHelper;
 import org.whispersystems.textsecuregcm.tests.util.AuthHelper;
+import org.whispersystems.textsecuregcm.util.CompletableFutureTestUtil;
 import org.whispersystems.textsecuregcm.util.MockUtils;
 import org.whispersystems.textsecuregcm.util.SystemMapper;
 import org.whispersystems.textsecuregcm.util.UsernameHashZkProofVerifier;
@@ -737,7 +739,7 @@ class AccountControllerTest {
   @Test
   void testDeleteUsername() {
     when(accountsManager.clearUsernameHash(any()))
-        .thenAnswer(invocation -> CompletableFuture.completedFuture(invocation.getArgument(0)));
+        .thenAnswer(invocation -> CompletableFutureTestUtil.almostCompletedFuture(invocation.getArgument(0)));
 
     Response response =
         resources.getJerseyTest()
@@ -746,6 +748,7 @@ class AccountControllerTest {
                  .header(HttpHeaders.AUTHORIZATION, AuthHelper.getAuthHeader(AuthHelper.VALID_UUID, AuthHelper.VALID_PASSWORD))
                  .delete();
 
+    assertThat(response.readEntity(String.class)).isEqualTo("");
     assertThat(response.getStatus()).isEqualTo(204);
     verify(accountsManager).clearUsernameHash(AuthHelper.VALID_ACCOUNT);
   }
@@ -828,6 +831,8 @@ class AccountControllerTest {
 
   @Test
   void testDeleteAccount() {
+    when(accountsManager.delete(any(), any())).thenReturn(CompletableFutureTestUtil.almostCompletedFuture(null));
+
     Response response =
             resources.getJerseyTest()
                      .target("/v1/accounts/me")

service/src/test/java/org/whispersystems/textsecuregcm/controllers/KeysControllerTest.java

@@ -74,6 +74,7 @@ import org.whispersystems.textsecuregcm.tests.util.AccountsHelper;
 import org.whispersystems.textsecuregcm.tests.util.AuthHelper;
 import org.whispersystems.textsecuregcm.tests.util.KeysHelper;
 import org.whispersystems.textsecuregcm.util.ByteArrayAdapter;
+import org.whispersystems.textsecuregcm.util.CompletableFutureTestUtil;
 
 @ExtendWith(DropwizardExtensionsSupport.class)
 class KeysControllerTest {
@@ -235,9 +236,9 @@ class KeysControllerTest {
 
     when(rateLimiters.getPreKeysLimiter()).thenReturn(rateLimiter);
 
-    when(KEYS.store(any(), anyByte(), any(), any(), any(), any())).thenReturn(CompletableFuture.completedFuture(null));
+    when(KEYS.store(any(), anyByte(), any(), any(), any(), any())).thenReturn(CompletableFutureTestUtil.almostCompletedFuture(null));
     when(KEYS.getEcSignedPreKey(any(), anyByte())).thenReturn(CompletableFuture.completedFuture(Optional.empty()));
-    when(KEYS.storeEcSignedPreKeys(any(), any())).thenReturn(CompletableFuture.completedFuture(null));
+    when(KEYS.storeEcSignedPreKeys(any(), any())).thenReturn(CompletableFutureTestUtil.almostCompletedFuture(null));
 
     when(KEYS.takeEC(EXISTS_UUID, sampleDeviceId)).thenReturn(
         CompletableFuture.completedFuture(Optional.of(SAMPLE_KEY)));

service/src/test/java/org/whispersystems/textsecuregcm/controllers/MessageControllerTest.java

@@ -121,6 +121,7 @@ import org.whispersystems.textsecuregcm.storage.ReportMessageManager;
 import org.whispersystems.textsecuregcm.tests.util.AccountsHelper;
 import org.whispersystems.textsecuregcm.tests.util.AuthHelper;
 import org.whispersystems.textsecuregcm.tests.util.KeysHelper;
+import org.whispersystems.textsecuregcm.util.CompletableFutureTestUtil;
 import org.whispersystems.textsecuregcm.util.Pair;
 import org.whispersystems.textsecuregcm.util.SystemMapper;
 import org.whispersystems.textsecuregcm.util.UUIDUtil;
@@ -610,19 +611,19 @@ class MessageControllerTest {
     UUID uuid1 = UUID.randomUUID();
     when(messagesManager.delete(AuthHelper.VALID_UUID, (byte) 1, uuid1, null))
         .thenReturn(
-            CompletableFuture.completedFuture(Optional.of(generateEnvelope(uuid1, Envelope.Type.CIPHERTEXT_VALUE,
+            CompletableFutureTestUtil.almostCompletedFuture(Optional.of(generateEnvelope(uuid1, Envelope.Type.CIPHERTEXT_VALUE,
                 timestamp, sourceUuid, (byte) 1, AuthHelper.VALID_UUID, null, "hi".getBytes(), 0))));
 
     UUID uuid2 = UUID.randomUUID();
     when(messagesManager.delete(AuthHelper.VALID_UUID, (byte) 1, uuid2, null))
         .thenReturn(
-            CompletableFuture.completedFuture(Optional.of(generateEnvelope(
+            CompletableFutureTestUtil.almostCompletedFuture(Optional.of(generateEnvelope(
                 uuid2, Envelope.Type.SERVER_DELIVERY_RECEIPT_VALUE,
                 System.currentTimeMillis(), sourceUuid, (byte) 1, AuthHelper.VALID_UUID, null, null, 0))));
 
     UUID uuid3 = UUID.randomUUID();
     when(messagesManager.delete(AuthHelper.VALID_UUID, (byte) 1, uuid3, null))
-        .thenReturn(CompletableFuture.completedFuture(Optional.empty()));
+        .thenReturn(CompletableFutureTestUtil.almostCompletedFuture(Optional.empty()));
 
     UUID uuid4 = UUID.randomUUID();
     when(messagesManager.delete(AuthHelper.VALID_UUID, (byte) 1, uuid4, null))

service/src/test/java/org/whispersystems/textsecuregcm/util/CompletableFutureTestUtil.java

@@ -10,6 +10,7 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionException;
+import java.util.concurrent.TimeUnit;
 
 public class CompletableFutureTestUtil {
 
@@ -24,4 +25,9 @@ public class CompletableFutureTestUtil {
     final CompletionException completionException = assertThrows(CompletionException.class, completableFuture::join, message);
     assertTrue(ExceptionUtils.unwrap(completionException).getClass().isAssignableFrom(expectedCause), message);
   }
+
+  public static <T> CompletableFuture<T> almostCompletedFuture(T result) {
+    return new CompletableFuture<T>().completeOnTimeout(result, 5, TimeUnit.MILLISECONDS);
+  }
+
 }