Remove unused Response.InternalServerError and Response.traceId

Response.InternalServerError was the only implementation of
Response#value() that threw an exception. Hence the throw clause from
Response#value() can be removed and callers can handle exceptions
specifically now.

Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: I083ea41990378058ad46d73bc7b4748801dab2da

java/com/google/gerrit/extensions/restapi/Response.java

@@ -14,10 +14,6 @@
 
 package com.google.gerrit.extensions.restapi;
 
-import static com.google.common.base.Preconditions.checkArgument;
-
-import com.google.gerrit.common.Nullable;
-import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 
 /** Special return value to mean specific HTTP status codes in a REST API. */
@@ -66,48 +62,24 @@ public abstract class Response<T> {
     return new Redirect(location);
   }
 
-  /**
-   * HTTP 500 Internal Server Error: failure due to an unexpected exception.
-   *
-   * <p>Can be returned from REST endpoints, instead of throwing the exception, if additional
-   * properties (e.g. a traceId) should be set on the response.
-   *
-   * @param cause the exception that caused the request to fail, must not be a {@link
-   *     RestApiException} because such an exception would result in a 4XX response code
-   */
-  public static <T> InternalServerError<T> internalServerError(Exception cause) {
-    return new InternalServerError<>(cause);
-  }
-
   /** Arbitrary status code with wrapped result. */
   public static <T> Response<T> withStatusCode(int statusCode, T value) {
     return new Impl<>(statusCode, value);
   }
 
   @SuppressWarnings({"unchecked", "rawtypes"})
-  public static <T> T unwrap(T obj) throws Exception {
+  public static <T> T unwrap(T obj) {
     while (obj instanceof Response) {
       obj = (T) ((Response) obj).value();
     }
     return obj;
   }
 
-  private String traceId;
-
-  public Response<T> traceId(@Nullable String traceId) {
-    this.traceId = traceId;
-    return this;
-  }
-
-  public Optional<String> traceId() {
-    return Optional.ofNullable(traceId);
-  }
-
   public abstract boolean isNone();
 
   public abstract int statusCode();
 
-  public abstract T value() throws Exception;
+  public abstract T value();
 
   public abstract CacheControl caching();
 
@@ -297,57 +269,4 @@ public abstract class Response<T> {
       return String.format("[202 Accepted] %s", location);
     }
   }
-
-  public static final class InternalServerError<T> extends Response<T> {
-    private final Exception cause;
-
-    private InternalServerError(Exception cause) {
-      checkArgument(!(cause instanceof RestApiException), "cause must not be a RestApiException");
-      this.cause = cause;
-    }
-
-    @Override
-    public boolean isNone() {
-      return false;
-    }
-
-    @Override
-    public int statusCode() {
-      return 500;
-    }
-
-    @Override
-    public T value() throws Exception {
-      throw cause();
-    }
-
-    @Override
-    public CacheControl caching() {
-      return CacheControl.NONE;
-    }
-
-    @Override
-    public Response<T> caching(CacheControl c) {
-      throw new UnsupportedOperationException();
-    }
-
-    public Exception cause() {
-      return cause;
-    }
-
-    @Override
-    public int hashCode() {
-      return cause.hashCode();
-    }
-
-    @Override
-    public boolean equals(Object o) {
-      return o instanceof InternalServerError && ((InternalServerError<?>) o).cause.equals(cause);
-    }
-
-    @Override
-    public String toString() {
-      return String.format("[500 Internal Server Error] %s", cause.getClass());
-    }
-  }
 }

java/com/google/gerrit/httpd/restapi/RestApiServlet.java

@@ -562,9 +562,6 @@ public class RestApiServlet extends HttpServlet {
             throw new ResourceNotFoundException();
           }
 
-          traceId = response.traceId();
-          traceId.ifPresent(traceId -> res.addHeader(X_GERRIT_TRACE, traceId));
-
           if (response instanceof Response.Redirect) {
             CacheHeaders.setNotCacheable(res);
             String location = ((Response.Redirect) response).location();
@@ -577,12 +574,6 @@ public class RestApiServlet extends HttpServlet {
             res.setHeader(HttpHeaders.LOCATION, ((Response.Accepted) response).location());
             logger.atFinest().log("REST call succeeded: %d", response.statusCode());
             return;
-          } else if (response instanceof Response.InternalServerError) {
-            // Rethrow the exception to have exactly the same error handling as if the REST endpoint
-            // would have thrown the exception directly, instead of returning
-            // Response.InternalServerError.
-            Exception cause = ((Response.InternalServerError<?>) response).cause();
-            throw cause;
           }
 
           status = response.statusCode();

java/com/google/gerrit/server/restapi/account/Stars.java

@@ -98,7 +98,8 @@ public class Stars implements ChildCollection<AccountResource, AccountResource.S
 
     @Override
     @SuppressWarnings("unchecked")
-    public Response<List<ChangeInfo>> apply(AccountResource rsrc) throws Exception {
+    public Response<List<ChangeInfo>> apply(AccountResource rsrc)
+        throws RestApiException, PermissionBackendException {
       if (!self.get().hasSameAccountId(rsrc.getUser())) {
         throw new AuthException("not allowed to list stars of another account");
       }

java/com/google/gerrit/server/restapi/change/Rebase.java

@@ -269,7 +269,8 @@ public class Rebase
     }
 
     @Override
-    public Response<ChangeInfo> apply(ChangeResource rsrc, RebaseInput input) throws Exception {
+    public Response<ChangeInfo> apply(ChangeResource rsrc, RebaseInput input)
+        throws RestApiException, UpdateException, IOException, PermissionBackendException {
       PatchSet ps = psUtil.current(rsrc.getNotes());
       if (ps == null) {
         throw new ResourceConflictException("current revision is missing");

java/com/google/gerrit/server/restapi/change/RevertSubmission.java

@@ -25,6 +25,7 @@ import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.RevertSubmissionInfo;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.Response;
+import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestModifyView;
 import com.google.gerrit.extensions.webui.UiAction;
 import com.google.gerrit.server.ChangeUtil;
@@ -33,10 +34,14 @@ import com.google.gerrit.server.PatchSetUtil;
 import com.google.gerrit.server.change.ChangeResource;
 import com.google.gerrit.server.permissions.ChangePermission;
 import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.project.ContributorAgreementsChecker;
+import com.google.gerrit.server.project.NoSuchChangeException;
+import com.google.gerrit.server.project.NoSuchProjectException;
 import com.google.gerrit.server.project.ProjectCache;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.query.change.InternalChangeQuery;
+import com.google.gerrit.server.update.UpdateException;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
@@ -44,6 +49,7 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import org.apache.commons.lang.RandomStringUtils;
+import org.eclipse.jgit.errors.ConfigInvalidException;
 
 @Singleton
 public class RevertSubmission
@@ -81,7 +87,8 @@ public class RevertSubmission
 
   @Override
   public Response<RevertSubmissionInfo> apply(ChangeResource changeResource, RevertInput input)
-      throws Exception {
+      throws RestApiException, NoSuchChangeException, IOException, UpdateException,
+          PermissionBackendException, NoSuchProjectException, ConfigInvalidException {
 
     if (!changeResource.getChange().isMerged()) {
       throw new ResourceConflictException(
@@ -117,7 +124,9 @@ public class RevertSubmission
   }
 
   private RevertSubmissionInfo revertSubmission(
-      List<ChangeData> changeDatas, RevertInput input, String submissionId) throws Exception {
+      List<ChangeData> changeDatas, RevertInput input, String submissionId)
+      throws RestApiException, NoSuchChangeException, IOException, UpdateException,
+          PermissionBackendException, NoSuchProjectException, ConfigInvalidException {
     List<ChangeInfo> results;
     results = new ArrayList<>();
     if (input.topic == null) {

java/com/google/gerrit/server/restapi/group/AddMembers.java

@@ -28,6 +28,7 @@ import com.google.gerrit.extensions.restapi.DefaultInput;
 import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.Response;
+import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestCollectionCreateView;
 import com.google.gerrit.extensions.restapi.RestModifyView;
 import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
@@ -222,7 +223,8 @@ public class AddMembers implements RestModifyView<GroupResource, Input> {
 
     @Override
     public Response<AccountInfo> apply(GroupResource resource, IdString id, Input input)
-        throws Exception {
+        throws RestApiException, NotInternalGroupException, IOException, ConfigInvalidException,
+            PermissionBackendException {
       AddMembers.Input in = new AddMembers.Input();
       in._oneMember = id.get();
       try {

java/com/google/gerrit/server/restapi/project/CreateDashboard.java

@@ -19,12 +19,15 @@ import com.google.gerrit.extensions.api.projects.SetDashboardInput;
 import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.Response;
+import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestCollectionCreateView;
+import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.project.DashboardResource;
 import com.google.gerrit.server.project.ProjectResource;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
+import java.io.IOException;
 import org.kohsuke.args4j.Option;
 
 @Singleton
@@ -42,7 +45,7 @@ public class CreateDashboard
 
   @Override
   public Response<DashboardInfo> apply(ProjectResource parent, IdString id, SetDashboardInput input)
-      throws Exception {
+      throws RestApiException, IOException, PermissionBackendException {
     parent.getProjectState().checkStatePermitsWrite();
     if (!DashboardsCollection.isDefaultDashboard(id)) {
       throw new ResourceNotFoundException(id);

java/com/google/gerrit/server/restapi/project/SetDefaultDashboard.java

@@ -24,9 +24,11 @@ import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.Response;
+import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestModifyView;
 import com.google.gerrit.server.git.meta.MetaDataUpdate;
 import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.permissions.ProjectPermission;
 import com.google.gerrit.server.project.DashboardResource;
 import com.google.gerrit.server.project.ProjectCache;
@@ -34,6 +36,7 @@ import com.google.gerrit.server.project.ProjectConfig;
 import com.google.gerrit.server.project.ProjectResource;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
+import java.io.IOException;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.errors.RepositoryNotFoundException;
 import org.kohsuke.args4j.Option;
@@ -67,7 +70,7 @@ class SetDefaultDashboard implements RestModifyView<DashboardResource, SetDashbo
 
   @Override
   public Response<DashboardInfo> apply(DashboardResource rsrc, SetDashboardInput input)
-      throws Exception {
+      throws RestApiException, IOException, PermissionBackendException {
     if (input == null) {
       input = new SetDashboardInput(); // Delete would set input to null.
     }

java/com/google/gerrit/sshd/commands/CreateGroupCommand.java

@@ -119,7 +119,8 @@ final class CreateGroupCommand extends SshCommand {
     }
   }
 
-  private GroupResource createGroup() throws Exception {
+  private GroupResource createGroup()
+      throws RestApiException, IOException, ConfigInvalidException, PermissionBackendException {
     GroupInput input = new GroupInput();
     input.description = groupDescription;
     input.visibleToAll = visibleToAll;

java/com/google/gerrit/sshd/commands/ShowCaches.java

@@ -197,7 +197,7 @@ final class ShowCaches extends SshCommand {
     stdout.flush();
   }
 
-  private Collection<CacheInfo> getCaches() throws Exception {
+  private Collection<CacheInfo> getCaches() {
     @SuppressWarnings("unchecked")
     Map<String, CacheInfo> caches =
         (Map<String, CacheInfo>) listCaches.apply(new ConfigResource()).value();