GET PUT DELETE Rest endpoints for change Assignee field

changes/<change-id>/assignee

GET returns an AccountInfo:
{
  "_account_id": 1000000,
  "email": "user@gerrit.com",
  "username": "user"
}

PUT takes an account identifier: name-email, email, full name, "self" and
returns an AccountInfo for the user that is assigned after the call.

Change-Id: Icce1be90c6c9558950502fe24435317e8372bb64

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/AssigneeInput.java

@@ -0,0 +1,22 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.extensions.api.changes;
+
+import com.google.gerrit.extensions.restapi.DefaultInput;
+
+public class AssigneeInput {
+  @DefaultInput
+  public String assignee;
+}

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/common/ChangeInfo.java

@@ -28,6 +28,7 @@ public class ChangeInfo {
   public String project;
   public String branch;
   public String topic;
+  public AccountInfo assignee;
   public Collection<String> hashtags;
   public String changeId;
   public String subject;

gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeJson.java

@@ -101,6 +101,8 @@ import com.google.gerrit.server.api.accounts.GpgApiAdapter;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.git.LabelNormalizer;
 import com.google.gerrit.server.git.MergeUtil;
+import com.google.gerrit.server.index.change.ChangeField;
+import com.google.gerrit.server.index.change.ChangeIndexCollection;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.notedb.ReviewerStateInternal;
 import com.google.gerrit.server.patch.PatchListNotAvailableException;
@@ -171,6 +173,7 @@ public class ChangeJson {
   private final ChangeNotes.Factory notesFactory;
   private final ChangeResource.Factory changeResourceFactory;
   private final ChangeKindCache changeKindCache;
+  private final ChangeIndexCollection indexes;
 
   private boolean lazyLoad = true;
   private AccountLoader accountLoader;
@@ -201,6 +204,7 @@ public class ChangeJson {
       ChangeNotes.Factory notesFactory,
       ChangeResource.Factory changeResourceFactory,
       ChangeKindCache changeKindCache,
+      ChangeIndexCollection indexes,
       @Assisted Set<ListChangesOption> options) {
     this.db = db;
     this.labelNormalizer = ln;
@@ -223,6 +227,7 @@ public class ChangeJson {
     this.notesFactory = notesFactory;
     this.changeResourceFactory = changeResourceFactory;
     this.changeKindCache = changeKindCache;
+    this.indexes = indexes;
     this.options = options.isEmpty()
         ? EnumSet.noneOf(ListChangesOption.class)
         : EnumSet.copyOf(options);
@@ -436,6 +441,11 @@ public class ChangeJson {
     out.project = in.getProject().get();
     out.branch = in.getDest().getShortName();
     out.topic = in.getTopic();
+    if (indexes.getSearchIndex().getSchema().hasField(ChangeField.ASSIGNEE)) {
+      if (cd.assignee().isPresent()) {
+        out.assignee = accountLoader.get(cd.assignee().get());
+      }
+    }
     out.hashtags = cd.hashtags();
     out.changeId = in.getKey().get();
     if (in.getStatus().isOpen()) {

gerrit-server/src/main/java/com/google/gerrit/server/change/DeleteAssignee.java

@@ -0,0 +1,130 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.change;
+
+import com.google.common.base.Optional;
+import com.google.gerrit.common.TimeUtil;
+import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.extensions.restapi.BadRequestException;
+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.reviewdb.client.Account;
+import com.google.gerrit.reviewdb.client.ChangeMessage;
+import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.ChangeMessagesUtil;
+import com.google.gerrit.server.ChangeUtil;
+import com.google.gerrit.server.change.DeleteAssignee.Input;
+import com.google.gerrit.server.account.AccountInfoCacheFactory;
+import com.google.gerrit.server.account.AccountJson;
+import com.google.gerrit.server.config.AnonymousCowardName;
+import com.google.gerrit.server.git.BatchUpdate;
+import com.google.gerrit.server.git.BatchUpdate.ChangeContext;
+import com.google.gerrit.server.git.UpdateException;
+import com.google.gerrit.server.notedb.ChangeUpdate;
+import com.google.gerrit.server.notedb.NotesMigration;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.Singleton;
+
+@Singleton
+public class DeleteAssignee implements
+    RestModifyView<ChangeResource, Input> {
+  public static class Input {
+
+  }
+  private BatchUpdate.Factory batchUpdateFactory;
+  private final NotesMigration notesMigration;
+  private final ChangeMessagesUtil cmUtil;
+  private final Provider<ReviewDb> db;
+  private final AccountInfoCacheFactory.Factory accountInfos;
+  private final String anonymousCowardName;
+
+  @Inject
+  DeleteAssignee(NotesMigration notesMigration,
+      BatchUpdate.Factory batchUpdateFactory,
+      ChangeMessagesUtil cmUtil,
+      Provider<ReviewDb> db,
+      AccountInfoCacheFactory.Factory accountInfosFactory,
+      @AnonymousCowardName String anonymousCowardName) {
+    this.batchUpdateFactory = batchUpdateFactory;
+    this.notesMigration = notesMigration;
+    this.cmUtil = cmUtil;
+    this.db = db;
+    this.accountInfos = accountInfosFactory;
+    this.anonymousCowardName = anonymousCowardName;
+  }
+
+  @Override
+  public Object apply(ChangeResource rsrc, Input input)
+      throws RestApiException, UpdateException
+       {
+    try (BatchUpdate bu = batchUpdateFactory.create(db.get(),
+        rsrc.getProject(),
+        rsrc.getUser(), TimeUtil.nowTs())) {
+      Op op = new Op();
+      bu.addOp(rsrc.getChange().getId(), op);
+      bu.execute();
+      if (op.getDeletedAssignee() == null) {
+        return Response.none();
+      }
+      return Response.ok(AccountJson.toAccountInfo(op.getDeletedAssignee()));
+    }
+  }
+
+  private class Op extends BatchUpdate.Op {
+    private Account deletedAssignee;
+
+    @Override
+    public boolean updateChange(ChangeContext ctx)
+        throws RestApiException, OrmException{
+      if (!notesMigration.readChanges()) {
+        throw new BadRequestException(
+            "Cannot add Assignee; NoteDb is disabled");
+      }
+      if (!ctx.getControl().canEditAssignee()) {
+        throw new AuthException("Delete Assignee not permitted");
+      }
+      ChangeUpdate update = ctx.getUpdate(ctx.getChange().currentPatchSetId());
+      Optional<Account.Id> currentAssigneeId = update.getNotes().getAssignee();
+      if (!currentAssigneeId.isPresent()) {
+        return false;
+      }
+      Account account = accountInfos.create().get(currentAssigneeId.get());
+      update.setAssignee(Optional.absent());
+      addMessage(ctx, update, account);
+      deletedAssignee = account;
+      return true;
+    }
+
+    public Account getDeletedAssignee() {
+      return deletedAssignee;
+    }
+
+    private void addMessage(BatchUpdate.ChangeContext ctx,
+        ChangeUpdate update, Account deleted) throws OrmException {
+      ChangeMessage cmsg = new ChangeMessage(
+          new ChangeMessage.Key(
+              ctx.getChange().getId(),
+              ChangeUtil.messageUUID(ctx.getDb())),
+          ctx.getAccountId(), ctx.getWhen(),
+          ctx.getChange().currentPatchSetId());
+      cmsg.setMessage(
+          "Assignee deleted: " + deleted.getName(anonymousCowardName));
+      cmUtil.addChangeMessage(ctx.getDb(), update, cmsg);
+    }
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/change/GetAssignee.java

@@ -0,0 +1,48 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.change;
+
+import com.google.common.base.Optional;
+import com.google.gerrit.extensions.common.AccountInfo;
+import com.google.gerrit.extensions.restapi.Response;
+import com.google.gerrit.extensions.restapi.RestReadView;
+import com.google.gerrit.reviewdb.client.Account;
+import com.google.gerrit.server.account.AccountInfoCacheFactory;
+import com.google.gerrit.server.account.AccountJson;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+
+@Singleton
+public class GetAssignee implements RestReadView<ChangeResource> {
+  private final AccountInfoCacheFactory.Factory accountInfo;
+
+  @Inject
+  GetAssignee(AccountInfoCacheFactory.Factory accountInfo) {
+    this.accountInfo = accountInfo;
+  }
+
+  @Override
+  public Response<AccountInfo> apply(ChangeResource rsrc) throws OrmException {
+
+    Optional<Account.Id> assignee =
+        rsrc.getControl().getNotes().load().getAssignee();
+    if (assignee.isPresent()) {
+      Account account = accountInfo.create().get(assignee.get());
+      return Response.ok(AccountJson.toAccountInfo(account));
+    }
+    return Response.none();
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/change/Module.java

@@ -53,6 +53,9 @@ public class Module extends RestApiModule {
     get(CHANGE_KIND, "detail").to(GetDetail.class);
     get(CHANGE_KIND, "topic").to(GetTopic.class);
     get(CHANGE_KIND, "in").to(IncludedIn.class);
+    get(CHANGE_KIND, "assignee").to(GetAssignee.class);
+    put(CHANGE_KIND, "assignee").to(PutAssignee.class);
+    delete(CHANGE_KIND, "assignee").to(DeleteAssignee.class);
     get(CHANGE_KIND, "hashtags").to(GetHashtags.class);
     get(CHANGE_KIND, "comments").to(ListChangeComments.class);
     get(CHANGE_KIND, "drafts").to(ListChangeDrafts.class);
@@ -139,6 +142,7 @@ public class Module extends RestApiModule {
     factory(PatchSetInserter.Factory.class);
     factory(RebaseChangeOp.Factory.class);
     factory(ReviewerResource.Factory.class);
+    factory(SetAssigneeOp.Factory.class);
     factory(SetHashtagsOp.Factory.class);
     factory(ChangeResource.Factory.class);
   }

gerrit-server/src/main/java/com/google/gerrit/server/change/PutAssignee.java

@@ -0,0 +1,60 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.change;
+
+import com.google.gerrit.common.TimeUtil;
+import com.google.gerrit.extensions.api.changes.AssigneeInput;
+import com.google.gerrit.extensions.common.AccountInfo;
+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.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.account.AccountJson;
+import com.google.gerrit.server.git.BatchUpdate;
+import com.google.gerrit.server.git.UpdateException;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.Singleton;
+
+@Singleton
+public class PutAssignee
+    implements RestModifyView<ChangeResource, AssigneeInput> {
+
+  private SetAssigneeOp.Factory assigneeFactory;
+  private BatchUpdate.Factory batchUpdateFactory;
+  private Provider<ReviewDb> db;
+
+  @Inject
+  PutAssignee(SetAssigneeOp.Factory assigneeFactory,
+      BatchUpdate.Factory batchUpdateFactory,
+      Provider<ReviewDb> db) {
+    this.assigneeFactory = assigneeFactory;
+    this.batchUpdateFactory = batchUpdateFactory;
+    this.db = db;
+  }
+
+  @Override
+  public Response<AccountInfo> apply(ChangeResource rsrc, AssigneeInput input)
+      throws RestApiException, UpdateException {
+    try (BatchUpdate bu = batchUpdateFactory.create(db.get(),
+        rsrc.getChange().getProject(), rsrc.getControl().getUser(),
+        TimeUtil.nowTs())) {
+      SetAssigneeOp op = assigneeFactory.create(input);
+      bu.addOp(rsrc.getId(), op);
+      bu.execute();
+      return Response.ok(AccountJson.toAccountInfo(op.getNewAssignee()));
+    }
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/change/SetAssigneeOp.java

@@ -0,0 +1,136 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.change;
+
+import com.google.common.base.Optional;
+import com.google.gerrit.extensions.api.changes.AssigneeInput;
+import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.extensions.restapi.BadRequestException;
+import com.google.gerrit.extensions.restapi.RestApiException;
+import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
+import com.google.gerrit.reviewdb.client.Account;
+import com.google.gerrit.reviewdb.client.ChangeMessage;
+import com.google.gerrit.server.ChangeMessagesUtil;
+import com.google.gerrit.server.ChangeUtil;
+import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.account.AccountInfoCacheFactory;
+import com.google.gerrit.server.account.AccountsCollection;
+import com.google.gerrit.server.config.AnonymousCowardName;
+import com.google.gerrit.server.git.BatchUpdate;
+import com.google.gerrit.server.notedb.ChangeUpdate;
+import com.google.gerrit.server.notedb.NotesMigration;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.assistedinject.Assisted;
+import com.google.inject.assistedinject.AssistedInject;
+
+public class SetAssigneeOp extends BatchUpdate.Op {
+  public interface Factory {
+    SetAssigneeOp create(AssigneeInput input);
+  }
+
+  private final AssigneeInput input;
+  private final AccountsCollection accounts;
+  private final ChangeMessagesUtil cmUtil;
+  private final AccountInfoCacheFactory.Factory accountInfosFactory;
+  private final NotesMigration notesMigration;
+  private final String anonymousCowardName;
+  private Account newAssignee;
+
+  @AssistedInject
+  SetAssigneeOp(AccountsCollection accounts,
+      NotesMigration notesMigration,
+      ChangeMessagesUtil cmUtil,
+      AccountInfoCacheFactory.Factory accountInfosFactory,
+      @AnonymousCowardName String anonymousCowardName,
+      @Assisted AssigneeInput input) {
+    this.accounts = accounts;
+    this.notesMigration = notesMigration;
+    this.cmUtil = cmUtil;
+    this.accountInfosFactory = accountInfosFactory;
+    this.anonymousCowardName = anonymousCowardName;
+    this.input = input;
+  }
+
+  @Override
+  public boolean updateChange(BatchUpdate.ChangeContext ctx)
+      throws OrmException, RestApiException {
+    if (!notesMigration.readChanges()) {
+      throw new BadRequestException(
+          "Cannot add Assignee; NoteDb is disabled");
+    }
+    if (!ctx.getControl().canEditAssignee()) {
+      throw new AuthException("Changing Assignee not permitted");
+    }
+    ChangeUpdate update = ctx.getUpdate(ctx.getChange().currentPatchSetId());
+    Optional<Account.Id> oldAssigneeId = update.getNotes().getAssignee();
+    if (input.assignee == null) {
+      if (oldAssigneeId != null && oldAssigneeId.isPresent()) {
+        throw new AuthException("Cannot set Assignee to empty");
+      }
+      return false;
+    }
+    Account oldAssignee = null;
+    if (oldAssigneeId != null && oldAssigneeId.isPresent()) {
+      oldAssignee = accountInfosFactory.create().get(oldAssigneeId.get());
+    }
+    IdentifiedUser newAssigneeUser = accounts.parse(input.assignee);
+    if (oldAssigneeId != null &&
+        oldAssigneeId.equals(newAssigneeUser.getAccountId())) {
+      newAssignee = oldAssignee;
+      return false;
+    }
+    if (!newAssigneeUser.getAccount().isActive()) {
+      throw new UnprocessableEntityException(String.format(
+          "Account of %s is not active", newAssigneeUser.getUserName()));
+    }
+    if (!ctx.getControl().forUser(newAssigneeUser).isRefVisible()) {
+      throw new AuthException(String.format(
+          "Change %s is not visible to %s.",
+          ctx.getChange().getChangeId(),
+          newAssigneeUser.getUserName()));
+    }
+    update.setAssignee(Optional.fromNullable(newAssigneeUser.getAccountId()));
+    this.newAssignee = newAssigneeUser.getAccount();
+    addMessage(ctx, update, oldAssignee);
+    return true;
+  }
+
+  private void addMessage(BatchUpdate.ChangeContext ctx, ChangeUpdate update,
+      Account previousAssignee) throws OrmException {
+    StringBuilder msg = new StringBuilder();
+    msg.append("Assignee ");
+    if (previousAssignee == null) {
+      msg.append("added: ");
+      msg.append(newAssignee.getName(anonymousCowardName));
+    } else {
+      msg.append("changed from: ");
+      msg.append(previousAssignee.getName(anonymousCowardName));
+      msg.append(" to: ");
+      msg.append(newAssignee.getName(anonymousCowardName));
+    }
+    ChangeMessage cmsg = new ChangeMessage(
+        new ChangeMessage.Key(
+            ctx.getChange().getId(),
+            ChangeUtil.messageUUID(ctx.getDb())),
+        ctx.getAccountId(), ctx.getWhen(),
+        ctx.getChange().currentPatchSetId());
+    cmsg.setMessage(msg.toString());
+    cmUtil.addChangeMessage(ctx.getDb(), update, cmsg);
+  }
+
+  public Account getNewAssignee() {
+    return newAssignee;
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotesParser.java

@@ -137,7 +137,7 @@ class ChangeNotesParser {
   private String branch;
   private Change.Status status;
   private String topic;
-  private Account.Id assignee;
+  private Optional<Account.Id> assignee;
   private Set<String> hashtags;
   private Timestamp createdOn;
   private Timestamp lastUpdatedOn;
@@ -212,7 +212,7 @@ class ChangeNotesParser {
         submissionId,
         status,
 
-        assignee,
+        assignee != null ? assignee.orNull() : null,
         hashtags,
         patchSets,
         buildApprovals(),
@@ -484,9 +484,14 @@ class ChangeNotesParser {
       return;
     }
     String assigneeValue = parseOneFooter(commit, FOOTER_ASSIGNEE);
-    if (assigneeValue != null) {
+    if (assigneeValue == null){
+      //footer not found
+    } else if (assigneeValue.equals("")) {
+      // empty footer found, assignee deleted
+      assignee = Optional.absent();
+    } else {
       PersonIdent ident = RawParseUtils.parsePersonIdent(assigneeValue);
-      assignee = noteUtil.parseIdent(ident, id);
+      assignee = Optional.fromNullable(noteUtil.parseIdent(ident, id));
     }
   }
 

gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeUpdate.java

@@ -125,7 +125,7 @@ public class ChangeUpdate extends AbstractChangeUpdate {
   private String submissionId;
   private String topic;
   private String commit;
-  private Account.Id assignee;
+  private Optional<Account.Id> assignee;
   private Set<String> hashtags;
   private String changeMessage;
   private String tag;
@@ -378,7 +378,7 @@ public class ChangeUpdate extends AbstractChangeUpdate {
     this.hashtags = hashtags;
   }
 
-  public void setAssignee(Account.Id assignee) {
+  public void setAssignee(Optional<Account.Id> assignee) {
     this.assignee = assignee;
   }
 
@@ -551,8 +551,12 @@ public class ChangeUpdate extends AbstractChangeUpdate {
     }
 
     if (assignee != null) {
-      addFooter(msg, FOOTER_ASSIGNEE);
+      if (assignee.isPresent()) {
-      addIdent(msg, assignee).append('\n');
+        addFooter(msg, FOOTER_ASSIGNEE);
+        addIdent(msg, assignee.get()).append('\n');
+      } else {
+        addFooter(msg, FOOTER_ASSIGNEE).append('\n');
+      }
     }
 
     Joiner comma = Joiner.on(',');

gerrit-server/src/main/java/com/google/gerrit/server/query/change/AssigneePredicate.java

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.query.change;
 
+import com.google.common.base.Optional;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.server.index.change.ChangeField;
 import com.google.gwtorm.server.OrmException;
@@ -29,9 +30,10 @@ class AssigneePredicate extends ChangeIndexPredicate {
   @Override
   public boolean match(final ChangeData object) throws OrmException {
     if (id.get() == ChangeField.NO_ASSIGNEE) {
-      return object.notes().load().getAssignee() == null;
+      Optional<Account.Id> assignee = object.notes().load().getAssignee();
+      return assignee == null || !assignee.isPresent();
     }
-    return id.equals(object.notes().load().getAssignee());
+    return id.equals(object.notes().load().getAssignee().get());
   }
 
   @Override

gerrit-server/src/test/java/com/google/gerrit/server/notedb/ChangeNotesTest.java

@@ -24,6 +24,7 @@ import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
 import static org.junit.Assert.fail;
 
+import com.google.common.base.Optional;
 import com.google.common.base.Throwables;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableListMultimap;
@@ -565,7 +566,7 @@ public class ChangeNotesTest extends AbstractChangeNotesTest {
   public void assigneeCommit() throws Exception {
     Change c = newChange();
     ChangeUpdate update = newUpdate(c, changeOwner);
-    update.setAssignee(otherUserId);
+    update.setAssignee(Optional.fromNullable(otherUserId));
     ObjectId result = update.commit();
     assertThat(result).isNotNull();
     try (RevWalk rw = new RevWalk(repo)) {
@@ -587,14 +588,14 @@ public class ChangeNotesTest extends AbstractChangeNotesTest {
   public void assigneeChangeNotes() throws Exception {
     Change c = newChange();
     ChangeUpdate update = newUpdate(c, changeOwner);
-    update.setAssignee(otherUserId);
+    update.setAssignee(Optional.fromNullable(otherUserId));
     update.commit();
 
     ChangeNotes notes = newNotes(c);
     assertThat(notes.getAssignee().get()).isEqualTo(otherUserId);
 
     update = newUpdate(c, changeOwner);
-    update.setAssignee(changeOwner.getAccountId());
+    update.setAssignee(Optional.fromNullable(changeOwner.getAccountId()));
     update.commit();
 
     notes = newNotes(c);