diff --git a/Documentation/config-labels.txt b/Documentation/config-labels.txt
index cf78c6d..3db621d 100644
--- a/Documentation/config-labels.txt
+++ b/Documentation/config-labels.txt
@@ -368,6 +368,9 @@
 ignored if the label doesn't apply for that branch.
 Additionally, the `branch` modifier has no effect when the submit rule
 is customized in the rules.pl of the project or inherited from parent projects.
+Branch can be a ref pattern similar to what is documented
+link:access-control.html#reference[here], but must not contain `${username}` or
+`${shardeduserid}`.
 
 [[label_example]]
 === Example
diff --git a/Documentation/rest-api-projects.txt b/Documentation/rest-api-projects.txt
index 54f8022..792cca8 100644
--- a/Documentation/rest-api-projects.txt
+++ b/Documentation/rest-api-projects.txt
@@ -1357,8 +1357,8 @@
 === Index project
 
 Adds or updates the current project (and children, if specified) in the secondary index.
-The indexing task is executed asynchronously in background, so this command
-returns immediately.
+The indexing task is executed asynchronously in background and this command returns
+immediately if `async` is specified in the input.
 
 As an input, a link:#index-project-input[IndexProjectInput] entity can be provided.
 
@@ -1369,6 +1369,7 @@
 
   {
     "index_children": "true"
+    "async": "true"
   }
 ----
 
@@ -3162,6 +3163,8 @@
 |Field Name         ||Description
 |`index_children`   ||
 If children should be indexed recursively.
+|`async`            ||
+If projects should be indexed asynchronously.
 |================================
 
 [[inherited-boolean-info]]
diff --git a/java/com/google/gerrit/common/data/PermissionRule.java b/java/com/google/gerrit/common/data/PermissionRule.java
index c50af5c..8ab0a55 100644
--- a/java/com/google/gerrit/common/data/PermissionRule.java
+++ b/java/com/google/gerrit/common/data/PermissionRule.java
@@ -66,27 +66,27 @@
     action = Action.BLOCK;
   }
 
-  public Boolean getForce() {
+  public boolean getForce() {
     return force;
   }
 
-  public void setForce(Boolean newForce) {
+  public void setForce(boolean newForce) {
     force = newForce;
   }
 
-  public Integer getMin() {
+  public int getMin() {
     return min;
   }
 
-  public void setMin(Integer min) {
+  public void setMin(int min) {
     this.min = min;
   }
 
-  public void setMax(Integer max) {
+  public void setMax(int max) {
     this.max = max;
   }
 
-  public Integer getMax() {
+  public int getMax() {
     return max;
   }
 
@@ -266,7 +266,7 @@
   }
 
   public boolean hasRange() {
-    return (!(getMin() == null || getMin() == 0)) || (!(getMax() == null || getMax() == 0));
+    return getMin() != 0 || getMax() != 0;
   }
 
   public static int parseInt(String value) {
diff --git a/java/com/google/gerrit/extensions/api/projects/IndexProjectInput.java b/java/com/google/gerrit/extensions/api/projects/IndexProjectInput.java
index a41f227..1b962c1 100644
--- a/java/com/google/gerrit/extensions/api/projects/IndexProjectInput.java
+++ b/java/com/google/gerrit/extensions/api/projects/IndexProjectInput.java
@@ -16,4 +16,5 @@
 
 public class IndexProjectInput {
   public Boolean indexChildren;
+  public Boolean async;
 }
diff --git a/java/com/google/gerrit/extensions/restapi/AcceptsPost.java b/java/com/google/gerrit/extensions/restapi/AcceptsPost.java
deleted file mode 100644
index da87d32..0000000
--- a/java/com/google/gerrit/extensions/restapi/AcceptsPost.java
+++ /dev/null
@@ -1,35 +0,0 @@
-// Copyright (C) 2012 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.restapi;
-
-/**
- * Optional interface for {@link RestCollection}.
- *
- * <p>Collections that implement this interface can accept a {@code POST} directly on the collection
- * itself when no id was given in the path. This interface is intended to be used with
- * TopLevelResource collections. Nested collections often bind POST on the parent collection to the
- * view implementation handling the insertion of a new member.
- */
-public interface AcceptsPost<P extends RestResource> {
-  /**
-   * Handle creation of a child resource by POST on the collection.
-   *
-   * @param parent parent collection handle.
-   * @return a view to perform the creation. The id of the newly created resource should be
-   *     determined from the input body.
-   * @throws RestApiException the view cannot be constructed.
-   */
-  RestModifyView<P, ?> post(P parent) throws RestApiException;
-}
diff --git a/java/com/google/gerrit/extensions/restapi/RestApiModule.java b/java/com/google/gerrit/extensions/restapi/RestApiModule.java
index ee31113..d47b094 100644
--- a/java/com/google/gerrit/extensions/restapi/RestApiModule.java
+++ b/java/com/google/gerrit/extensions/restapi/RestApiModule.java
@@ -29,6 +29,7 @@
   protected static final String DELETE = "DELETE";
   protected static final String POST = "POST";
   protected static final String CREATE = "CREATE";
+  protected static final String POST_ON_COLLECTION = "POST_ON_COLLECTION";
 
   protected <R extends RestResource> ReadViewBinder<R> get(TypeLiteral<RestView<R>> viewType) {
     return get(viewType, "/");
@@ -46,6 +47,12 @@
     return delete(viewType, "/");
   }
 
+  protected <R extends RestResource> RestCollectionViewBinder<R> postOnCollection(
+      TypeLiteral<RestView<R>> viewType) {
+    return new RestCollectionViewBinder<>(
+        bind(viewType).annotatedWith(export(POST_ON_COLLECTION, "/")));
+  }
+
   protected <R extends RestResource> CreateViewBinder<R> create(TypeLiteral<RestView<R>> viewType) {
     return new CreateViewBinder<>(bind(viewType).annotatedWith(export(CREATE, "/")));
   }
@@ -142,6 +149,33 @@
     }
   }
 
+  public static class RestCollectionViewBinder<C extends RestResource> {
+    private final LinkedBindingBuilder<RestView<C>> binder;
+
+    private RestCollectionViewBinder(LinkedBindingBuilder<RestView<C>> binder) {
+      this.binder = binder;
+    }
+
+    public <P extends RestResource, T extends RestCollectionView<P, C, ?>> ScopedBindingBuilder to(
+        Class<T> impl) {
+      return binder.to(impl);
+    }
+
+    public <P extends RestResource, T extends RestCollectionView<P, C, ?>> void toInstance(T impl) {
+      binder.toInstance(impl);
+    }
+
+    public <P extends RestResource, T extends RestCollectionView<P, C, ?>>
+        ScopedBindingBuilder toProvider(Class<? extends Provider<? extends T>> providerType) {
+      return binder.toProvider(providerType);
+    }
+
+    public <P extends RestResource, T extends RestCollectionView<P, C, ?>>
+        ScopedBindingBuilder toProvider(Provider<? extends T> provider) {
+      return binder.toProvider(provider);
+    }
+  }
+
   public static class CreateViewBinder<C extends RestResource> {
     private final LinkedBindingBuilder<RestView<C>> binder;
 
diff --git a/java/com/google/gerrit/extensions/restapi/RestCollectionView.java b/java/com/google/gerrit/extensions/restapi/RestCollectionView.java
new file mode 100644
index 0000000..7e8eef0
--- /dev/null
+++ b/java/com/google/gerrit/extensions/restapi/RestCollectionView.java
@@ -0,0 +1,31 @@
+// Copyright (C) 2018 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.restapi;
+
+/**
+ * RestView on a RestCollection that supports accepting input.
+ *
+ * <p>The input must be supplied as JSON as the body of the HTTP request. RestCollectionViews can
+ * only be invoked by the HTTP method {@code POST}.
+ *
+ * @param <P> type of the parent resource
+ * @param <C> type of the child resource
+ * @param <I> type of input the JSON parser will parse the input into.
+ */
+public interface RestCollectionView<P extends RestResource, C extends RestResource, I>
+    extends RestView<C> {
+
+  Object apply(P parentResource, I input) throws Exception;
+}
diff --git a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
index a454c00..599e98f 100644
--- a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
+++ b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
@@ -69,7 +69,6 @@
 import com.google.gerrit.extensions.registration.DynamicItem;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AcceptsDelete;
-import com.google.gerrit.extensions.restapi.AcceptsPost;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.BinaryResult;
@@ -87,6 +86,7 @@
 import com.google.gerrit.extensions.restapi.Response;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestCollection;
+import com.google.gerrit.extensions.restapi.RestCollectionView;
 import com.google.gerrit.extensions.restapi.RestCreateView;
 import com.google.gerrit.extensions.restapi.RestModifyView;
 import com.google.gerrit.extensions.restapi.RestReadView;
@@ -308,12 +308,14 @@
 
         if (isRead(req)) {
           viewData = new ViewData(null, rc.list());
-        } else if (rc instanceof AcceptsPost && isPost(req)) {
-          @SuppressWarnings("unchecked")
-          AcceptsPost<RestResource> ac = (AcceptsPost<RestResource>) rc;
-          viewData = new ViewData(null, ac.post(rsrc));
-        } else {
-          throw new MethodNotAllowedException();
+        } else if (isPost(req)) {
+          RestView<RestResource> restCollectionView =
+              rc.views().get("gerrit", "POST_ON_COLLECTION./");
+          if (restCollectionView != null) {
+            viewData = new ViewData(null, restCollectionView);
+          } else {
+            throw new MethodNotAllowedException();
+          }
         }
       } else {
         IdString id = path.remove(0);
@@ -350,10 +352,14 @@
         if (path.isEmpty()) {
           if (isRead(req)) {
             viewData = new ViewData(null, c.list());
-          } else if (c instanceof AcceptsPost && isPost(req)) {
-            @SuppressWarnings("unchecked")
-            AcceptsPost<RestResource> ac = (AcceptsPost<RestResource>) c;
-            viewData = new ViewData(null, ac.post(rsrc));
+          } else if (isPost(req)) {
+            RestView<RestResource> restCollectionView =
+                c.views().get(viewData.pluginName, "POST_ON_COLLECTION./");
+            if (restCollectionView != null) {
+              viewData = new ViewData(null, restCollectionView);
+            } else {
+              throw new MethodNotAllowedException();
+            }
           } else if (c instanceof AcceptsDelete && isDelete(req)) {
             @SuppressWarnings("unchecked")
             AcceptsDelete<RestResource> ac = (AcceptsDelete<RestResource>) c;
@@ -434,6 +440,19 @@
             ServletUtils.consumeRequestBody(is);
           }
         }
+      } else if (viewData.view instanceof RestCollectionView<?, ?, ?>) {
+        @SuppressWarnings("unchecked")
+        RestCollectionView<RestResource, RestResource, Object> m =
+            (RestCollectionView<RestResource, RestResource, Object>) viewData.view;
+
+        Type type = inputType(m);
+        inputRequestBody = parseRequest(req, type);
+        result = m.apply(rsrc, inputRequestBody);
+        if (inputRequestBody instanceof RawInput) {
+          try (InputStream is = req.getInputStream()) {
+            ServletUtils.consumeRequestBody(is);
+          }
+        }
       } else {
         throw new ResourceNotFoundException();
       }
@@ -778,6 +797,24 @@
     return ((ParameterizedType) supertype).getActualTypeArguments()[2];
   }
 
+  private static Type inputType(RestCollectionView<RestResource, RestResource, Object> m) {
+    // MyCollectionView implements RestCollectionView<SomeResource, SomeResource, MyInput>
+    TypeLiteral<?> typeLiteral = TypeLiteral.get(m.getClass());
+
+    // RestCollectionView<SomeResource, SomeResource, MyInput>
+    // This is smart enough to resolve even when there are intervening subclasses, even if they have
+    // reordered type arguments.
+    TypeLiteral<?> supertypeLiteral = typeLiteral.getSupertype(RestCollectionView.class);
+
+    Type supertype = supertypeLiteral.getType();
+    checkState(
+        supertype instanceof ParameterizedType,
+        "supertype of %s is not parameterized: %s",
+        typeLiteral,
+        supertypeLiteral);
+    return ((ParameterizedType) supertype).getActualTypeArguments()[2];
+  }
+
   private Object parseRequest(HttpServletRequest req, Type type)
       throws IOException, BadRequestException, SecurityException, IllegalArgumentException,
           NoSuchMethodException, IllegalAccessException, InstantiationException,
@@ -1142,11 +1179,12 @@
     String name = method + "." + p.get(0);
     RestView<RestResource> core = views.get("gerrit", name);
     if (core != null) {
-      return new ViewData(null, core);
+      return new ViewData("gerrit", core);
     }
+
     core = views.get("gerrit", "GET." + p.get(0));
     if (core != null) {
-      return new ViewData(null, core);
+      return new ViewData("gerrit", core);
     }
 
     Map<String, RestView<RestResource>> r = new TreeMap<>();
diff --git a/java/com/google/gerrit/server/ApprovalCopier.java b/java/com/google/gerrit/server/ApprovalCopier.java
index 922922c..095263e 100644
--- a/java/com/google/gerrit/server/ApprovalCopier.java
+++ b/java/com/google/gerrit/server/ApprovalCopier.java
@@ -79,7 +79,6 @@
    *
    * @param db review database.
    * @param notes change notes for user uploading PatchSet
-   * @param user user uploading PatchSet
    * @param ps new PatchSet
    * @param rw open walk that can read the patch set commit; null to open the repo on demand.
    * @param repoConfig repo config used for change kind detection; null to read from repo on demand.
@@ -88,12 +87,11 @@
   public void copyInReviewDb(
       ReviewDb db,
       ChangeNotes notes,
-      CurrentUser user,
       PatchSet ps,
       @Nullable RevWalk rw,
       @Nullable Config repoConfig)
       throws OrmException {
-    copyInReviewDb(db, notes, user, ps, rw, repoConfig, Collections.emptyList());
+    copyInReviewDb(db, notes, ps, rw, repoConfig, Collections.emptyList());
   }
 
   /**
@@ -101,7 +99,6 @@
    *
    * @param db review database.
    * @param notes change notes for user uploading PatchSet
-   * @param user user uploading PatchSet
    * @param ps new PatchSet
    * @param rw open walk that can read the patch set commit; null to open the repo on demand.
    * @param repoConfig repo config used for change kind detection; null to read from repo on demand.
@@ -111,33 +108,30 @@
   public void copyInReviewDb(
       ReviewDb db,
       ChangeNotes notes,
-      CurrentUser user,
       PatchSet ps,
       @Nullable RevWalk rw,
       @Nullable Config repoConfig,
       Iterable<PatchSetApproval> dontCopy)
       throws OrmException {
     if (PrimaryStorage.of(notes.getChange()) == PrimaryStorage.REVIEW_DB) {
-      db.patchSetApprovals().insert(getForPatchSet(db, notes, user, ps, rw, repoConfig, dontCopy));
+      db.patchSetApprovals().insert(getForPatchSet(db, notes, ps, rw, repoConfig, dontCopy));
     }
   }
 
   Iterable<PatchSetApproval> getForPatchSet(
       ReviewDb db,
       ChangeNotes notes,
-      CurrentUser user,
       PatchSet.Id psId,
       @Nullable RevWalk rw,
       @Nullable Config repoConfig)
       throws OrmException {
     return getForPatchSet(
-        db, notes, user, psId, rw, repoConfig, Collections.<PatchSetApproval>emptyList());
+        db, notes, psId, rw, repoConfig, Collections.<PatchSetApproval>emptyList());
   }
 
   Iterable<PatchSetApproval> getForPatchSet(
       ReviewDb db,
       ChangeNotes notes,
-      CurrentUser user,
       PatchSet.Id psId,
       @Nullable RevWalk rw,
       @Nullable Config repoConfig,
@@ -147,13 +141,12 @@
     if (ps == null) {
       return Collections.emptyList();
     }
-    return getForPatchSet(db, notes, user, ps, rw, repoConfig, dontCopy);
+    return getForPatchSet(db, notes, ps, rw, repoConfig, dontCopy);
   }
 
   private Iterable<PatchSetApproval> getForPatchSet(
       ReviewDb db,
       ChangeNotes notes,
-      CurrentUser user,
       PatchSet ps,
       @Nullable RevWalk rw,
       @Nullable Config repoConfig,
@@ -211,7 +204,7 @@
           byUser.put(psa.getLabel(), psa.getAccountId(), copy(psa, ps.getId()));
         }
       }
-      return labelNormalizer.normalize(notes, user, byUser.values()).getNormalized();
+      return labelNormalizer.normalize(notes, byUser.values()).getNormalized();
     } catch (IOException e) {
       throw new OrmException(e);
     }
diff --git a/java/com/google/gerrit/server/ApprovalsUtil.java b/java/com/google/gerrit/server/ApprovalsUtil.java
index 8365ddb..0d12eca 100644
--- a/java/com/google/gerrit/server/ApprovalsUtil.java
+++ b/java/com/google/gerrit/server/ApprovalsUtil.java
@@ -388,7 +388,6 @@
   public Iterable<PatchSetApproval> byPatchSet(
       ReviewDb db,
       ChangeNotes notes,
-      CurrentUser user,
       PatchSet.Id psId,
       @Nullable RevWalk rw,
       @Nullable Config repoConfig)
@@ -396,13 +395,12 @@
     if (!migration.readChanges()) {
       return sortApprovals(db.patchSetApprovals().byPatchSet(psId));
     }
-    return copier.getForPatchSet(db, notes, user, psId, rw, repoConfig);
+    return copier.getForPatchSet(db, notes, psId, rw, repoConfig);
   }
 
   public Iterable<PatchSetApproval> byPatchSetUser(
       ReviewDb db,
       ChangeNotes notes,
-      CurrentUser user,
       PatchSet.Id psId,
       Account.Id accountId,
       @Nullable RevWalk rw,
@@ -411,7 +409,7 @@
     if (!migration.readChanges()) {
       return sortApprovals(db.patchSetApprovals().byPatchSetUser(psId, accountId));
     }
-    return filterApprovals(byPatchSet(db, notes, user, psId, rw, repoConfig), accountId);
+    return filterApprovals(byPatchSet(db, notes, psId, rw, repoConfig), accountId);
   }
 
   public PatchSetApproval getSubmitter(ReviewDb db, ChangeNotes notes, PatchSet.Id c) {
diff --git a/java/com/google/gerrit/server/PatchSetUtil.java b/java/com/google/gerrit/server/PatchSetUtil.java
index c9ca972..fe42a61 100644
--- a/java/com/google/gerrit/server/PatchSetUtil.java
+++ b/java/com/google/gerrit/server/PatchSetUtil.java
@@ -181,17 +181,16 @@
   }
 
   /** Check if the current patch set of the change is locked. */
-  public void checkPatchSetNotLocked(ChangeNotes notes, CurrentUser user)
+  public void checkPatchSetNotLocked(ChangeNotes notes)
       throws OrmException, IOException, ResourceConflictException {
-    if (isPatchSetLocked(notes, user)) {
+    if (isPatchSetLocked(notes)) {
       throw new ResourceConflictException(
           String.format("The current patch set of change %s is locked", notes.getChangeId()));
     }
   }
 
   /** Is the current patch set locked against state changes? */
-  public boolean isPatchSetLocked(ChangeNotes notes, CurrentUser user)
-      throws OrmException, IOException {
+  public boolean isPatchSetLocked(ChangeNotes notes) throws OrmException, IOException {
     Change change = notes.getChange();
     if (change.getStatus() == Change.Status.MERGED) {
       return false;
@@ -202,9 +201,8 @@
 
     ApprovalsUtil approvalsUtil = approvalsUtilProvider.get();
     for (PatchSetApproval ap :
-        approvalsUtil.byPatchSet(
-            dbProvider.get(), notes, user, change.currentPatchSetId(), null, null)) {
-      LabelType type = projectState.getLabelTypes(notes, user).byLabel(ap.getLabel());
+        approvalsUtil.byPatchSet(dbProvider.get(), notes, change.currentPatchSetId(), null, null)) {
+      LabelType type = projectState.getLabelTypes(notes).byLabel(ap.getLabel());
       if (type != null
           && ap.getValue() == 1
           && type.getFunction() == LabelFunction.PATCH_SET_LOCK) {
diff --git a/java/com/google/gerrit/server/change/ChangeInserter.java b/java/com/google/gerrit/server/change/ChangeInserter.java
index c6fe93b..8ca364b 100644
--- a/java/com/google/gerrit/server/change/ChangeInserter.java
+++ b/java/com/google/gerrit/server/change/ChangeInserter.java
@@ -521,8 +521,7 @@
     if (fireRevisionCreated) {
       revisionCreated.fire(change, patchSet, ctx.getAccount(), ctx.getWhen(), notify);
       if (approvals != null && !approvals.isEmpty()) {
-        List<LabelType> labels =
-            projectState.getLabelTypes(change.getDest(), ctx.getUser()).getLabelTypes();
+        List<LabelType> labels = projectState.getLabelTypes(change.getDest()).getLabelTypes();
         Map<String, Short> allApprovals = new HashMap<>();
         Map<String, Short> oldApprovals = new HashMap<>();
         for (LabelType lt : labels) {
diff --git a/java/com/google/gerrit/server/change/ChangeJson.java b/java/com/google/gerrit/server/change/ChangeJson.java
index 2feea47..a5bcf48 100644
--- a/java/com/google/gerrit/server/change/ChangeJson.java
+++ b/java/com/google/gerrit/server/change/ChangeJson.java
@@ -658,10 +658,9 @@
       // list permitted labels, since users can't vote on those patch sets.
       if (user.isIdentifiedUser()
           && (!limitToPsId.isPresent() || limitToPsId.get().equals(in.currentPatchSetId()))) {
-        PermissionBackend.ForChange perm = permissionBackendForChange(user, cd);
         out.permittedLabels =
             cd.change().getStatus() != Change.Status.ABANDONED
-                ? permittedLabels(perm, cd)
+                ? permittedLabels(user.getAccountId(), cd)
                 : ImmutableMap.of();
       }
 
@@ -889,7 +888,7 @@
     LabelTypes labelTypes = cd.getLabelTypes();
     for (Account.Id accountId : allUsers) {
       PermissionBackend.ForChange perm = permissionBackendForChange(accountId, cd);
-      Map<String, VotingRangeInfo> pvr = getPermittedVotingRanges(permittedLabels(perm, cd));
+      Map<String, VotingRangeInfo> pvr = getPermittedVotingRanges(permittedLabels(accountId, cd));
       for (Map.Entry<String, LabelWithStatus> e : labels.entrySet()) {
         LabelType lt = labelTypes.byLabel(e.getKey());
         if (lt == null) {
@@ -1030,8 +1029,7 @@
       Map<String, ApprovalInfo> byLabel = Maps.newHashMapWithExpectedSize(labels.size());
       Map<String, VotingRangeInfo> pvr = Collections.emptyMap();
       if (detailed) {
-        PermissionBackend.ForChange perm = permissionBackendForChange(accountId, cd);
-        pvr = getPermittedVotingRanges(permittedLabels(perm, cd));
+        pvr = getPermittedVotingRanges(permittedLabels(accountId, cd));
         for (Map.Entry<String, LabelWithStatus> entry : labels.entrySet()) {
           ApprovalInfo ai = approvalInfo(accountId, 0, null, null, null);
           byLabel.put(entry.getKey(), ai);
@@ -1106,8 +1104,7 @@
   }
 
   private Map<String, Collection<String>> permittedLabels(
-      PermissionBackend.ForChange perm, ChangeData cd)
-      throws OrmException, PermissionBackendException {
+      Account.Id filterApprovalsBy, ChangeData cd) throws OrmException, PermissionBackendException {
     boolean isMerged = cd.change().getStatus() == Change.Status.MERGED;
     LabelTypes labelTypes = cd.getLabelTypes();
     Map<String, LabelType> toCheck = new HashMap<>();
@@ -1123,7 +1120,8 @@
     }
 
     Map<String, Short> labels = null;
-    Set<LabelPermission.WithValue> can = perm.testLabels(toCheck.values());
+    Set<LabelPermission.WithValue> can =
+        permissionBackendForChange(filterApprovalsBy, cd).testLabels(toCheck.values());
     SetMultimap<String, String> permitted = LinkedHashMultimap.create();
     for (SubmitRecord rec : submitRecords(cd)) {
       if (rec.labels == null) {
@@ -1139,7 +1137,7 @@
           boolean ok = can.contains(new LabelPermission.WithValue(type, v));
           if (isMerged) {
             if (labels == null) {
-              labels = currentLabels(perm, cd);
+              labels = currentLabels(filterApprovalsBy, cd);
             }
             short prev = labels.getOrDefault(type.getName(), (short) 0);
             ok &= v.getValue() >= prev;
@@ -1163,17 +1161,15 @@
     return permitted.asMap();
   }
 
-  private Map<String, Short> currentLabels(PermissionBackend.ForChange perm, ChangeData cd)
+  private Map<String, Short> currentLabels(Account.Id accountId, ChangeData cd)
       throws OrmException {
-    IdentifiedUser user = perm.user().asIdentifiedUser();
     Map<String, Short> result = new HashMap<>();
     for (PatchSetApproval psa :
         approvalsUtil.byPatchSetUser(
             db.get(),
             lazyLoad ? cd.notes() : notesFactory.createFromIndexedChange(cd.change()),
-            user,
             cd.change().currentPatchSetId(),
-            user.getAccountId(),
+            accountId,
             null,
             null)) {
       result.put(psa.getLabel(), psa.getValue());
diff --git a/java/com/google/gerrit/server/change/LabelNormalizer.java b/java/com/google/gerrit/server/change/LabelNormalizer.java
index f4dbf21..1ec1717 100644
--- a/java/com/google/gerrit/server/change/LabelNormalizer.java
+++ b/java/com/google/gerrit/server/change/LabelNormalizer.java
@@ -26,11 +26,8 @@
 import com.google.gerrit.common.data.LabelValue;
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.PatchSetApproval;
-import com.google.gerrit.server.CurrentUser;
-import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.project.ProjectCache;
-import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
 import java.io.IOException;
@@ -71,43 +68,25 @@
     }
   }
 
-  private final IdentifiedUser.GenericFactory userFactory;
   private final ProjectCache projectCache;
 
   @Inject
-  LabelNormalizer(IdentifiedUser.GenericFactory userFactory, ProjectCache projectCache) {
-    this.userFactory = userFactory;
+  LabelNormalizer(ProjectCache projectCache) {
     this.projectCache = projectCache;
   }
 
   /**
-   * @param notes change containing the given approvals.
+   * @param notes change notes containing the given approvals.
    * @param approvals list of approvals.
    * @return copies of approvals normalized to the defined ranges for the label type. Approvals for
    *     unknown labels are not included in the output.
-   * @throws OrmException
    */
   public Result normalize(ChangeNotes notes, Collection<PatchSetApproval> approvals)
-      throws OrmException, IOException {
-    IdentifiedUser user = userFactory.create(notes.getChange().getOwner());
-    return normalize(notes, user, approvals);
-  }
-
-  /**
-   * @param notes change notes containing the given approvals.
-   * @param user current user.
-   * @param approvals list of approvals.
-   * @return copies of approvals normalized to the defined ranges for the label type. Approvals for
-   *     unknown labels are not included in the output.
-   */
-  public Result normalize(
-      ChangeNotes notes, CurrentUser user, Collection<PatchSetApproval> approvals)
       throws IOException {
     List<PatchSetApproval> unchanged = Lists.newArrayListWithCapacity(approvals.size());
     List<PatchSetApproval> updated = Lists.newArrayListWithCapacity(approvals.size());
     List<PatchSetApproval> deleted = Lists.newArrayListWithCapacity(approvals.size());
-    LabelTypes labelTypes =
-        projectCache.checkedGet(notes.getProjectName()).getLabelTypes(notes, user);
+    LabelTypes labelTypes = projectCache.checkedGet(notes.getProjectName()).getLabelTypes(notes);
     for (PatchSetApproval psa : approvals) {
       Change.Id changeId = psa.getKey().getParentKey().getParentKey();
       checkArgument(
diff --git a/java/com/google/gerrit/server/change/PatchSetInserter.java b/java/com/google/gerrit/server/change/PatchSetInserter.java
index b979240..d71a93d 100644
--- a/java/com/google/gerrit/server/change/PatchSetInserter.java
+++ b/java/com/google/gerrit/server/change/PatchSetInserter.java
@@ -273,12 +273,7 @@
     change.setCurrentPatchSet(patchSetInfo);
     if (copyApprovals) {
       approvalCopier.copyInReviewDb(
-          db,
-          ctx.getNotes(),
-          ctx.getUser(),
-          patchSet,
-          ctx.getRevWalk(),
-          ctx.getRepoView().getConfig());
+          db, ctx.getNotes(), patchSet, ctx.getRevWalk(), ctx.getRepoView().getConfig());
     }
     if (changeMessage != null) {
       cmUtil.addChangeMessage(db, update, changeMessage);
@@ -314,7 +309,7 @@
       throws AuthException, ResourceConflictException, IOException, PermissionBackendException,
           OrmException {
     // Not allowed to create a new patch set if the current patch set is locked.
-    psUtil.checkPatchSetNotLocked(origNotes, ctx.getUser());
+    psUtil.checkPatchSetNotLocked(origNotes);
 
     if (checkAddPatchSetPermission) {
       permissionBackend
diff --git a/java/com/google/gerrit/server/edit/ChangeEditModifier.java b/java/com/google/gerrit/server/edit/ChangeEditModifier.java
index 80d1cd1..a8c463d 100644
--- a/java/com/google/gerrit/server/edit/ChangeEditModifier.java
+++ b/java/com/google/gerrit/server/edit/ChangeEditModifier.java
@@ -408,7 +408,7 @@
     }
 
     // Not allowed to edit if the current patch set is locked.
-    patchSetUtil.checkPatchSetNotLocked(notes, currentUser.get());
+    patchSetUtil.checkPatchSetNotLocked(notes);
     try {
       permissionBackend
           .currentUser()
diff --git a/java/com/google/gerrit/server/git/MergeUtil.java b/java/com/google/gerrit/server/git/MergeUtil.java
index 637be24..0231378 100644
--- a/java/com/google/gerrit/server/git/MergeUtil.java
+++ b/java/com/google/gerrit/server/git/MergeUtil.java
@@ -361,7 +361,7 @@
 
     PatchSetApproval submitAudit = null;
 
-    for (PatchSetApproval a : safeGetApprovals(notes, user, psId)) {
+    for (PatchSetApproval a : safeGetApprovals(notes, psId)) {
       if (a.getValue() <= 0) {
         // Negative votes aren't counted.
         continue;
@@ -460,10 +460,9 @@
     return "Verified".equalsIgnoreCase(id.get());
   }
 
-  private Iterable<PatchSetApproval> safeGetApprovals(
-      ChangeNotes notes, CurrentUser user, PatchSet.Id psId) {
+  private Iterable<PatchSetApproval> safeGetApprovals(ChangeNotes notes, PatchSet.Id psId) {
     try {
-      return approvalsUtil.byPatchSet(db.get(), notes, user, psId, null, null);
+      return approvalsUtil.byPatchSet(db.get(), notes, psId, null, null);
     } catch (OrmException e) {
       logger.atSevere().withCause(e).log("Can't read approval records for %s", psId);
       return Collections.emptyList();
diff --git a/java/com/google/gerrit/server/git/receive/ReceiveCommits.java b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
index dd79f3f..d5b1966 100644
--- a/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
+++ b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
@@ -2444,7 +2444,7 @@
       RevCommit priorCommit = revisions.inverse().get(priorPatchSet);
 
       // Not allowed to create a new patch set if the current patch set is locked.
-      if (psUtil.isPatchSetLocked(notes, user)) {
+      if (psUtil.isPatchSetLocked(notes)) {
         reject(inputCommand, "cannot add patch set to " + ontoChange + ".");
         return false;
       }
diff --git a/java/com/google/gerrit/server/git/receive/ReplaceOp.java b/java/com/google/gerrit/server/git/receive/ReplaceOp.java
index 36c5005..3e7942f 100644
--- a/java/com/google/gerrit/server/git/receive/ReplaceOp.java
+++ b/java/com/google/gerrit/server/git/receive/ReplaceOp.java
@@ -309,7 +309,6 @@
     approvalCopier.copyInReviewDb(
         ctx.getDb(),
         ctx.getNotes(),
-        ctx.getUser(),
         newPatchSet,
         ctx.getRevWalk(),
         ctx.getRepoView().getConfig(),
@@ -408,7 +407,6 @@
           approvalsUtil.byPatchSetUser(
               ctx.getDb(),
               ctx.getNotes(),
-              ctx.getUser(),
               priorPatchSetId,
               ctx.getAccountId(),
               ctx.getRevWalk(),
@@ -541,10 +539,7 @@
      * show a transition from an oldValue of 0 to the new value.
      */
     List<LabelType> labels =
-        projectCache
-            .checkedGet(ctx.getProject())
-            .getLabelTypes(notes, ctx.getUser())
-            .getLabelTypes();
+        projectCache.checkedGet(ctx.getProject()).getLabelTypes(notes).getLabelTypes();
     Map<String, Short> allApprovals = new HashMap<>();
     Map<String, Short> oldApprovals = new HashMap<>();
     for (LabelType lt : labels) {
diff --git a/java/com/google/gerrit/server/mail/receive/MailProcessor.java b/java/com/google/gerrit/server/mail/receive/MailProcessor.java
index 0e0bca6..bf76bde 100644
--- a/java/com/google/gerrit/server/mail/receive/MailProcessor.java
+++ b/java/com/google/gerrit/server/mail/receive/MailProcessor.java
@@ -323,7 +323,6 @@
           .byPatchSetUser(
               ctx.getDb(),
               notes,
-              ctx.getUser(),
               psId,
               ctx.getAccountId(),
               ctx.getRevWalk(),
diff --git a/java/com/google/gerrit/server/mail/send/MergedSender.java b/java/com/google/gerrit/server/mail/send/MergedSender.java
index cf9257c..34f959c 100644
--- a/java/com/google/gerrit/server/mail/send/MergedSender.java
+++ b/java/com/google/gerrit/server/mail/send/MergedSender.java
@@ -70,12 +70,7 @@
       Table<Account.Id, String, PatchSetApproval> neg = HashBasedTable.create();
       for (PatchSetApproval ca :
           args.approvalsUtil.byPatchSet(
-              args.db.get(),
-              changeData.notes(),
-              args.identifiedUserFactory.create(changeData.change().getOwner()),
-              patchSet.getId(),
-              null,
-              null)) {
+              args.db.get(), changeData.notes(), patchSet.getId(), null, null)) {
         LabelType lt = labelTypes.byLabel(ca.getLabelId());
         if (lt == null) {
           continue;
diff --git a/java/com/google/gerrit/server/notedb/ChangeNoteUtil.java b/java/com/google/gerrit/server/notedb/ChangeNoteUtil.java
index cf86c99..5a4d1f5 100644
--- a/java/com/google/gerrit/server/notedb/ChangeNoteUtil.java
+++ b/java/com/google/gerrit/server/notedb/ChangeNoteUtil.java
@@ -16,12 +16,9 @@
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.gerrit.reviewdb.client.Account;
-import com.google.gerrit.server.account.AccountCache;
-import com.google.gerrit.server.account.AccountState;
 import com.google.gerrit.server.config.GerritServerId;
 import com.google.inject.Inject;
 import java.util.Date;
-import java.util.Optional;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.revwalk.FooterKey;
 
@@ -65,17 +62,13 @@
 
   private final LegacyChangeNoteRead legacyChangeNoteRead;
   private final ChangeNoteJson changeNoteJson;
-
-  private final AccountCache accountCache;
   private final String serverId;
 
   @Inject
   public ChangeNoteUtil(
       ChangeNoteJson changeNoteJson,
       LegacyChangeNoteRead legacyChangeNoteRead,
-      AccountCache accountCache,
       @GerritServerId String serverId) {
-    this.accountCache = accountCache;
     this.serverId = serverId;
     this.changeNoteJson = changeNoteJson;
     this.legacyChangeNoteRead = legacyChangeNoteRead;
@@ -90,9 +83,8 @@
   }
 
   public PersonIdent newIdent(Account.Id authorId, Date when, PersonIdent serverIdent) {
-    Optional<Account> author = accountCache.get(authorId).map(AccountState::getAccount);
     return new PersonIdent(
-        author.map(Account::getName).orElseGet(() -> Account.getName(authorId)),
+        "Gerrit User " + authorId.toString(),
         authorId.get() + "@" + serverId,
         when,
         serverIdent.getTimeZone());
@@ -101,6 +93,9 @@
   @VisibleForTesting
   public PersonIdent newIdent(Account author, Date when, PersonIdent serverIdent) {
     return new PersonIdent(
-        author.getName(), author.getId().get() + "@" + serverId, when, serverIdent.getTimeZone());
+        "Gerrit User " + author.getId(),
+        author.getId().get() + "@" + serverId,
+        when,
+        serverIdent.getTimeZone());
   }
 }
diff --git a/java/com/google/gerrit/server/notedb/LegacyChangeNoteWrite.java b/java/com/google/gerrit/server/notedb/LegacyChangeNoteWrite.java
index 1cf0c7c..7c946b8 100644
--- a/java/com/google/gerrit/server/notedb/LegacyChangeNoteWrite.java
+++ b/java/com/google/gerrit/server/notedb/LegacyChangeNoteWrite.java
@@ -23,8 +23,6 @@
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.Comment;
 import com.google.gerrit.server.GerritPersonIdent;
-import com.google.gerrit.server.account.AccountCache;
-import com.google.gerrit.server.account.AccountState;
 import com.google.gerrit.server.config.GerritServerId;
 import com.google.inject.Inject;
 import java.io.OutputStream;
@@ -35,39 +33,30 @@
 import java.util.Collections;
 import java.util.Date;
 import java.util.List;
-import java.util.Optional;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.util.QuotedString;
 
 public class LegacyChangeNoteWrite {
 
-  private final AccountCache accountCache;
   private final PersonIdent serverIdent;
   private final String serverId;
 
   @Inject
   public LegacyChangeNoteWrite(
-      AccountCache accountCache,
-      @GerritPersonIdent PersonIdent serverIdent,
-      @GerritServerId String serverId) {
-    this.accountCache = accountCache;
+      @GerritPersonIdent PersonIdent serverIdent, @GerritServerId String serverId) {
     this.serverIdent = serverIdent;
     this.serverId = serverId;
   }
 
   public PersonIdent newIdent(Account.Id authorId, Date when, PersonIdent serverIdent) {
-    Optional<Account> author = accountCache.get(authorId).map(AccountState::getAccount);
     return new PersonIdent(
-        author.map(Account::getName).orElseGet(() -> Account.getName(authorId)),
-        authorId.get() + "@" + serverId,
-        when,
-        serverIdent.getTimeZone());
+        authorId.toString(), authorId.get() + "@" + serverId, when, serverIdent.getTimeZone());
   }
 
   @VisibleForTesting
   public PersonIdent newIdent(Account author, Date when, PersonIdent serverIdent) {
     return new PersonIdent(
-        author.getName(), author.getId().get() + "@" + serverId, when, serverIdent.getTimeZone());
+        author.toString(), author.getId().get() + "@" + serverId, when, serverIdent.getTimeZone());
   }
 
   public String getServerId() {
diff --git a/java/com/google/gerrit/server/permissions/ChangeControl.java b/java/com/google/gerrit/server/permissions/ChangeControl.java
index bb752a0..d4d1e67 100644
--- a/java/com/google/gerrit/server/permissions/ChangeControl.java
+++ b/java/com/google/gerrit/server/permissions/ChangeControl.java
@@ -23,6 +23,7 @@
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.common.data.Permission;
 import com.google.gerrit.common.data.PermissionRange;
+import com.google.gerrit.extensions.conditions.BooleanCondition;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.Change;
@@ -263,13 +264,8 @@
     }
 
     @Override
-    public CurrentUser user() {
-      return getUser();
-    }
-
-    @Override
     public ForChange user(CurrentUser user) {
-      return user().equals(user) ? this : forUser(user).asForChange(cd, db);
+      return getUser().equals(user) ? this : forUser(user).asForChange(cd, db);
     }
 
     @Override
@@ -308,6 +304,11 @@
       return ok;
     }
 
+    @Override
+    public BooleanCondition testCond(ChangePermissionOrLabel perm) {
+      return new PermissionBackendCondition.ForChange(this, perm, getUser());
+    }
+
     private boolean can(ChangePermissionOrLabel perm) throws PermissionBackendException {
       if (perm instanceof ChangePermission) {
         return can((ChangePermission) perm);
diff --git a/java/com/google/gerrit/server/permissions/DefaultPermissionBackend.java b/java/com/google/gerrit/server/permissions/DefaultPermissionBackend.java
index 490b45e..bf68026 100644
--- a/java/com/google/gerrit/server/permissions/DefaultPermissionBackend.java
+++ b/java/com/google/gerrit/server/permissions/DefaultPermissionBackend.java
@@ -23,6 +23,7 @@
 import com.google.gerrit.common.data.PermissionRule.Action;
 import com.google.gerrit.extensions.api.access.GlobalOrPluginPermission;
 import com.google.gerrit.extensions.api.access.PluginPermission;
+import com.google.gerrit.extensions.conditions.BooleanCondition;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.AccountGroup;
@@ -32,6 +33,7 @@
 import com.google.gerrit.server.PeerDaemonUser;
 import com.google.gerrit.server.account.CapabilityCollection;
 import com.google.gerrit.server.cache.PerThreadCache;
+import com.google.gerrit.server.permissions.PermissionBackendCondition.WithUser;
 import com.google.gerrit.server.project.ProjectCache;
 import com.google.gerrit.server.project.ProjectState;
 import com.google.inject.Inject;
@@ -98,11 +100,6 @@
     }
 
     @Override
-    public CurrentUser user() {
-      return user;
-    }
-
-    @Override
     public ForProject project(Project.NameKey project) {
       try {
         ProjectState state = projectCache.checkedGet(project);
@@ -138,6 +135,11 @@
       return ok;
     }
 
+    @Override
+    public BooleanCondition testCond(GlobalOrPluginPermission perm) {
+      return new PermissionBackendCondition.WithUser(this, perm, user);
+    }
+
     private boolean can(GlobalOrPluginPermission perm) throws PermissionBackendException {
       if (perm instanceof GlobalPermission) {
         return can((GlobalPermission) perm);
diff --git a/java/com/google/gerrit/server/permissions/FailedPermissionBackend.java b/java/com/google/gerrit/server/permissions/FailedPermissionBackend.java
index 431bfd9..6c6f136 100644
--- a/java/com/google/gerrit/server/permissions/FailedPermissionBackend.java
+++ b/java/com/google/gerrit/server/permissions/FailedPermissionBackend.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.server.permissions;
 
 import com.google.gerrit.extensions.api.access.GlobalOrPluginPermission;
+import com.google.gerrit.extensions.conditions.BooleanCondition;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.server.ReviewDb;
@@ -84,11 +85,6 @@
     }
 
     @Override
-    public CurrentUser user() {
-      throw new UnsupportedOperationException("FailedPermissionBackend is not scoped to user");
-    }
-
-    @Override
     public ForProject project(Project.NameKey project) {
       return new FailedProject(message, cause);
     }
@@ -103,6 +99,12 @@
         throws PermissionBackendException {
       throw new PermissionBackendException(message, cause);
     }
+
+    @Override
+    public BooleanCondition testCond(GlobalOrPluginPermission perm) {
+      throw new UnsupportedOperationException(
+          "FailedPermissionBackend does not support conditions");
+    }
   }
 
   private static class FailedProject extends ForProject {
@@ -120,11 +122,6 @@
     }
 
     @Override
-    public CurrentUser user() {
-      throw new UnsupportedOperationException("FailedPermissionBackend is not scoped to user");
-    }
-
-    @Override
     public ForProject user(CurrentUser user) {
       return this;
     }
@@ -157,6 +154,12 @@
     }
 
     @Override
+    public BooleanCondition testCond(ProjectPermission perm) {
+      throw new UnsupportedOperationException(
+          "FailedPermissionBackend does not support conditions");
+    }
+
+    @Override
     public Map<String, Ref> filter(Map<String, Ref> refs, Repository repo, RefFilterOptions opts)
         throws PermissionBackendException {
       throw new PermissionBackendException(message, cause);
@@ -178,11 +181,6 @@
     }
 
     @Override
-    public CurrentUser user() {
-      throw new UnsupportedOperationException("FailedPermissionBackend is not scoped to user");
-    }
-
-    @Override
     public ForRef user(CurrentUser user) {
       return this;
     }
@@ -223,6 +221,12 @@
         throws PermissionBackendException {
       throw new PermissionBackendException(message, cause);
     }
+
+    @Override
+    public BooleanCondition testCond(RefPermission perm) {
+      throw new UnsupportedOperationException(
+          "FailedPermissionBackend does not support conditions");
+    }
   }
 
   private static class FailedChange extends ForChange {
@@ -267,8 +271,9 @@
     }
 
     @Override
-    public CurrentUser user() {
-      throw new UnsupportedOperationException("FailedPermissionBackend is not scoped to user");
+    public BooleanCondition testCond(ChangePermissionOrLabel perm) {
+      throw new UnsupportedOperationException(
+          "FailedPermissionBackend does not support conditions");
     }
   }
 }
diff --git a/java/com/google/gerrit/server/permissions/PermissionBackend.java b/java/com/google/gerrit/server/permissions/PermissionBackend.java
index 357770d..0690d6c 100644
--- a/java/com/google/gerrit/server/permissions/PermissionBackend.java
+++ b/java/com/google/gerrit/server/permissions/PermissionBackend.java
@@ -173,9 +173,6 @@
 
   /** PermissionBackend scoped to a specific user. */
   public abstract static class WithUser extends AcceptsReviewDb<WithUser> {
-    /** Returns the user this instance is scoped to. */
-    public abstract CurrentUser user();
-
     /** Returns an instance scoped for the specified project. */
     public abstract ForProject project(Project.NameKey project);
 
@@ -257,9 +254,7 @@
       }
     }
 
-    public BooleanCondition testCond(GlobalOrPluginPermission perm) {
-      return new PermissionBackendCondition.WithUser(this, perm);
-    }
+    public abstract BooleanCondition testCond(GlobalOrPluginPermission perm);
 
     /**
      * Filter a set of projects using {@code check(perm)}.
@@ -296,9 +291,6 @@
 
   /** PermissionBackend scoped to a user and project. */
   public abstract static class ForProject extends AcceptsReviewDb<ForProject> {
-    /** Returns the user this instance is scoped to. */
-    public abstract CurrentUser user();
-
     /** Returns the fully qualified resource path that this instance is scoped to. */
     public abstract String resourcePath();
 
@@ -355,9 +347,7 @@
       }
     }
 
-    public BooleanCondition testCond(ProjectPermission perm) {
-      return new PermissionBackendCondition.ForProject(this, perm);
-    }
+    public abstract BooleanCondition testCond(ProjectPermission perm);
 
     /**
      * Filter a map of references by visibility.
@@ -407,9 +397,6 @@
 
   /** PermissionBackend scoped to a user, project and reference. */
   public abstract static class ForRef extends AcceptsReviewDb<ForRef> {
-    /** Returns the user this instance is scoped to. */
-    public abstract CurrentUser user();
-
     /** Returns a fully qualified resource path that this instance is scoped to. */
     public abstract String resourcePath();
 
@@ -461,16 +448,11 @@
       }
     }
 
-    public BooleanCondition testCond(RefPermission perm) {
-      return new PermissionBackendCondition.ForRef(this, perm);
-    }
+    public abstract BooleanCondition testCond(RefPermission perm);
   }
 
   /** PermissionBackend scoped to a user, project, reference and change. */
   public abstract static class ForChange extends AcceptsReviewDb<ForChange> {
-    /** Returns the user this instance is scoped to. */
-    public abstract CurrentUser user();
-
     /** Returns the fully qualified resource path that this instance is scoped to. */
     public abstract String resourcePath();
 
@@ -511,9 +493,7 @@
       }
     }
 
-    public BooleanCondition testCond(ChangePermissionOrLabel perm) {
-      return new PermissionBackendCondition.ForChange(this, perm);
-    }
+    public abstract BooleanCondition testCond(ChangePermissionOrLabel perm);
 
     /**
      * Test which values of a label the user may be able to set.
diff --git a/java/com/google/gerrit/server/permissions/PermissionBackendCondition.java b/java/com/google/gerrit/server/permissions/PermissionBackendCondition.java
index 3a661cda..1b6b087 100644
--- a/java/com/google/gerrit/server/permissions/PermissionBackendCondition.java
+++ b/java/com/google/gerrit/server/permissions/PermissionBackendCondition.java
@@ -56,10 +56,13 @@
   public static class WithUser extends PermissionBackendCondition {
     private final PermissionBackend.WithUser impl;
     private final GlobalOrPluginPermission perm;
+    private final CurrentUser user;
 
-    WithUser(PermissionBackend.WithUser impl, GlobalOrPluginPermission perm) {
+    public WithUser(
+        PermissionBackend.WithUser impl, GlobalOrPluginPermission perm, CurrentUser user) {
       this.impl = impl;
       this.perm = perm;
+      this.user = user;
     }
 
     public PermissionBackend.WithUser withUser() {
@@ -82,7 +85,7 @@
 
     @Override
     public int hashCode() {
-      return Objects.hash(perm, hashForUser(impl.user()));
+      return Objects.hash(perm, hashForUser(user));
     }
 
     @Override
@@ -91,17 +94,19 @@
         return false;
       }
       WithUser other = (WithUser) obj;
-      return Objects.equals(perm, other.perm) && usersAreEqual(impl.user(), other.impl.user());
+      return Objects.equals(perm, other.perm) && usersAreEqual(user, other.user);
     }
   }
 
   public static class ForProject extends PermissionBackendCondition {
     private final PermissionBackend.ForProject impl;
     private final ProjectPermission perm;
+    private final CurrentUser user;
 
-    ForProject(PermissionBackend.ForProject impl, ProjectPermission perm) {
+    public ForProject(PermissionBackend.ForProject impl, ProjectPermission perm, CurrentUser user) {
       this.impl = impl;
       this.perm = perm;
+      this.user = user;
     }
 
     public PermissionBackend.ForProject project() {
@@ -124,7 +129,7 @@
 
     @Override
     public int hashCode() {
-      return Objects.hash(perm, impl.resourcePath(), hashForUser(impl.user()));
+      return Objects.hash(perm, impl.resourcePath(), hashForUser(user));
     }
 
     @Override
@@ -135,17 +140,19 @@
       ForProject other = (ForProject) obj;
       return Objects.equals(perm, other.perm)
           && Objects.equals(impl.resourcePath(), other.impl.resourcePath())
-          && usersAreEqual(impl.user(), other.impl.user());
+          && usersAreEqual(user, other.user);
     }
   }
 
   public static class ForRef extends PermissionBackendCondition {
     private final PermissionBackend.ForRef impl;
     private final RefPermission perm;
+    private final CurrentUser user;
 
-    ForRef(PermissionBackend.ForRef impl, RefPermission perm) {
+    public ForRef(PermissionBackend.ForRef impl, RefPermission perm, CurrentUser user) {
       this.impl = impl;
       this.perm = perm;
+      this.user = user;
     }
 
     public PermissionBackend.ForRef ref() {
@@ -168,7 +175,7 @@
 
     @Override
     public int hashCode() {
-      return Objects.hash(perm, impl.resourcePath(), hashForUser(impl.user()));
+      return Objects.hash(perm, impl.resourcePath(), hashForUser(user));
     }
 
     @Override
@@ -179,17 +186,20 @@
       ForRef other = (ForRef) obj;
       return Objects.equals(perm, other.perm)
           && Objects.equals(impl.resourcePath(), other.impl.resourcePath())
-          && usersAreEqual(impl.user(), other.impl.user());
+          && usersAreEqual(user, other.user);
     }
   }
 
   public static class ForChange extends PermissionBackendCondition {
     private final PermissionBackend.ForChange impl;
     private final ChangePermissionOrLabel perm;
+    private final CurrentUser user;
 
-    ForChange(PermissionBackend.ForChange impl, ChangePermissionOrLabel perm) {
+    public ForChange(
+        PermissionBackend.ForChange impl, ChangePermissionOrLabel perm, CurrentUser user) {
       this.impl = impl;
       this.perm = perm;
+      this.user = user;
     }
 
     public PermissionBackend.ForChange change() {
@@ -212,7 +222,7 @@
 
     @Override
     public int hashCode() {
-      return Objects.hash(perm, impl.resourcePath(), hashForUser(impl.user()));
+      return Objects.hash(perm, impl.resourcePath(), hashForUser(user));
     }
 
     @Override
@@ -223,7 +233,7 @@
       ForChange other = (ForChange) obj;
       return Objects.equals(perm, other.perm)
           && Objects.equals(impl.resourcePath(), other.impl.resourcePath())
-          && usersAreEqual(impl.user(), other.impl.user());
+          && usersAreEqual(user, other.user);
     }
   }
 
diff --git a/java/com/google/gerrit/server/permissions/ProjectControl.java b/java/com/google/gerrit/server/permissions/ProjectControl.java
index 2d2a64d..ed12a2b 100644
--- a/java/com/google/gerrit/server/permissions/ProjectControl.java
+++ b/java/com/google/gerrit/server/permissions/ProjectControl.java
@@ -19,6 +19,7 @@
 import com.google.gerrit.common.data.AccessSection;
 import com.google.gerrit.common.data.Permission;
 import com.google.gerrit.common.data.PermissionRule;
+import com.google.gerrit.extensions.conditions.BooleanCondition;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.AccountGroup;
@@ -323,11 +324,6 @@
     private String resourcePath;
 
     @Override
-    public CurrentUser user() {
-      return getUser();
-    }
-
-    @Override
     public ForProject user(CurrentUser user) {
       return forUser(user).asForProject().database(db);
     }
@@ -395,6 +391,11 @@
     }
 
     @Override
+    public BooleanCondition testCond(ProjectPermission perm) {
+      return new PermissionBackendCondition.ForProject(this, perm, getUser());
+    }
+
+    @Override
     public Map<String, Ref> filter(Map<String, Ref> refs, Repository repo, RefFilterOptions opts)
         throws PermissionBackendException {
       if (refFilter == null) {
diff --git a/java/com/google/gerrit/server/permissions/RefControl.java b/java/com/google/gerrit/server/permissions/RefControl.java
index f68a7a2..012d68a 100644
--- a/java/com/google/gerrit/server/permissions/RefControl.java
+++ b/java/com/google/gerrit/server/permissions/RefControl.java
@@ -20,6 +20,7 @@
 import com.google.gerrit.common.data.PermissionRange;
 import com.google.gerrit.common.data.PermissionRule;
 import com.google.gerrit.common.data.PermissionRule.Action;
+import com.google.gerrit.extensions.conditions.BooleanCondition;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.Change;
@@ -408,11 +409,6 @@
     private String resourcePath;
 
     @Override
-    public CurrentUser user() {
-      return getUser();
-    }
-
-    @Override
     public ForRef user(CurrentUser user) {
       return forUser(user).asForRef().database(db);
     }
@@ -480,6 +476,11 @@
       return ok;
     }
 
+    @Override
+    public BooleanCondition testCond(RefPermission perm) {
+      return new PermissionBackendCondition.ForRef(this, perm, getUser());
+    }
+
     private boolean can(RefPermission perm) throws PermissionBackendException {
       switch (perm) {
         case READ:
diff --git a/java/com/google/gerrit/server/project/ContributorAgreementsChecker.java b/java/com/google/gerrit/server/project/ContributorAgreementsChecker.java
index d840123..c3c76de 100644
--- a/java/com/google/gerrit/server/project/ContributorAgreementsChecker.java
+++ b/java/com/google/gerrit/server/project/ContributorAgreementsChecker.java
@@ -108,7 +108,11 @@
 
     if (!iUser.getEffectiveGroups().containsAnyOf(okGroupIds)) {
       final StringBuilder msg = new StringBuilder();
-      msg.append("A Contributor Agreement must be completed before uploading");
+      msg.append("No Contributor Agreement on file for user ")
+          .append(iUser.getNameEmail())
+          .append(" (id=")
+          .append(iUser.getAccountId())
+          .append(")");
       if (canonicalWebUrl != null) {
         msg.append(":\n\n  ");
         msg.append(canonicalWebUrl);
diff --git a/java/com/google/gerrit/server/project/ProjectState.java b/java/com/google/gerrit/server/project/ProjectState.java
index a490f10..87dbcfc 100644
--- a/java/com/google/gerrit/server/project/ProjectState.java
+++ b/java/com/google/gerrit/server/project/ProjectState.java
@@ -40,7 +40,6 @@
 import com.google.gerrit.reviewdb.client.Branch;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.client.RefNames;
-import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.account.CapabilityCollection;
 import com.google.gerrit.server.config.AllProjectsName;
 import com.google.gerrit.server.config.AllUsersName;
@@ -394,13 +393,13 @@
     return labelTypes;
   }
 
-  /** All available label types for this change and user. */
-  public LabelTypes getLabelTypes(ChangeNotes notes, CurrentUser user) {
-    return getLabelTypes(notes.getChange().getDest(), user);
+  /** All available label types for this change. */
+  public LabelTypes getLabelTypes(ChangeNotes notes) {
+    return getLabelTypes(notes.getChange().getDest());
   }
 
-  /** All available label types for this branch and user. */
-  public LabelTypes getLabelTypes(Branch.NameKey destination, CurrentUser user) {
+  /** All available label types for this branch. */
+  public LabelTypes getLabelTypes(Branch.NameKey destination) {
     List<LabelType> all = getLabelTypes().getLabelTypes();
 
     List<LabelType> r = Lists.newArrayListWithCapacity(all.size());
@@ -410,7 +409,15 @@
         r.add(l);
       } else {
         for (String refPattern : refs) {
-          if (RefConfigSection.isValid(refPattern) && match(destination, refPattern, user)) {
+          if (refPattern.contains("${")) {
+            logger.atWarning().log(
+                "Ref pattern for label %s in project %s contains illegal expanded parameters: %s."
+                    + " Ref pattern will be ignored.",
+                l, getName(), refPattern);
+            continue;
+          }
+
+          if (RefConfigSection.isValid(refPattern) && match(destination, refPattern)) {
             r.add(l);
             break;
           }
@@ -558,7 +565,7 @@
     return new LabelTypes(Collections.unmodifiableList(all));
   }
 
-  private boolean match(Branch.NameKey destination, String refPattern, CurrentUser user) {
-    return RefPatternMatcher.getMatcher(refPattern).match(destination.get(), user);
+  private boolean match(Branch.NameKey destination, String refPattern) {
+    return RefPatternMatcher.getMatcher(refPattern).match(destination.get(), null);
   }
 }
diff --git a/java/com/google/gerrit/server/query/change/ChangeData.java b/java/com/google/gerrit/server/query/change/ChangeData.java
index 1a336fc..1813211 100644
--- a/java/com/google/gerrit/server/query/change/ChangeData.java
+++ b/java/com/google/gerrit/server/query/change/ChangeData.java
@@ -51,7 +51,6 @@
 import com.google.gerrit.server.ChangeMessagesUtil;
 import com.google.gerrit.server.CommentsUtil;
 import com.google.gerrit.server.CurrentUser;
-import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.PatchSetUtil;
 import com.google.gerrit.server.ReviewerByEmailSet;
 import com.google.gerrit.server.ReviewerSet;
@@ -325,7 +324,7 @@
     ChangeData cd =
         new ChangeData(
             null, null, null, null, null, null, null, null, null, null, null, null, null, null,
-            null, null, null, null, project, id, null, null);
+            null, null, null, project, id, null, null);
     cd.currentPatchSet = new PatchSet(new PatchSet.Id(id, currentPatchSetId));
     return cd;
   }
@@ -338,7 +337,6 @@
   private final ChangeNotes.Factory notesFactory;
   private final CommentsUtil commentsUtil;
   private final GitRepositoryManager repoManager;
-  private final IdentifiedUser.GenericFactory userFactory;
   private final MergeUtil.Factory mergeUtilFactory;
   private final MergeabilityCache mergeabilityCache;
   private final NotesMigration notesMigration;
@@ -407,7 +405,6 @@
       ChangeNotes.Factory notesFactory,
       CommentsUtil commentsUtil,
       GitRepositoryManager repoManager,
-      IdentifiedUser.GenericFactory userFactory,
       MergeUtil.Factory mergeUtilFactory,
       MergeabilityCache mergeabilityCache,
       NotesMigration notesMigration,
@@ -428,7 +425,6 @@
     this.notesFactory = notesFactory;
     this.commentsUtil = commentsUtil;
     this.repoManager = repoManager;
-    this.userFactory = userFactory;
     this.mergeUtilFactory = mergeUtilFactory;
     this.mergeabilityCache = mergeabilityCache;
     this.notesMigration = notesMigration;
@@ -590,7 +586,7 @@
       } catch (IOException e) {
         throw new OrmException("project state not available", e);
       }
-      labelTypes = state.getLabelTypes(change().getDest(), userFactory.create(change().getOwner()));
+      labelTypes = state.getLabelTypes(change().getDest());
     }
     return labelTypes;
   }
@@ -633,13 +629,7 @@
         try {
           currentApprovals =
               ImmutableList.copyOf(
-                  approvalsUtil.byPatchSet(
-                      db,
-                      notes(),
-                      userFactory.create(c.getOwner()),
-                      c.currentPatchSetId(),
-                      null,
-                      null));
+                  approvalsUtil.byPatchSet(db, notes(), c.currentPatchSetId(), null, null));
         } catch (OrmException e) {
           if (e.getCause() instanceof NoSuchChangeException) {
             currentApprovals = Collections.emptyList();
diff --git a/java/com/google/gerrit/server/restapi/account/AddSshKey.java b/java/com/google/gerrit/server/restapi/account/AddSshKey.java
index ab06e25..9d9c1e3 100644
--- a/java/com/google/gerrit/server/restapi/account/AddSshKey.java
+++ b/java/com/google/gerrit/server/restapi/account/AddSshKey.java
@@ -26,7 +26,7 @@
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.RawInput;
 import com.google.gerrit.extensions.restapi.Response;
-import com.google.gerrit.extensions.restapi.RestModifyView;
+import com.google.gerrit.extensions.restapi.RestCollectionView;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.account.AccountResource;
@@ -46,7 +46,8 @@
 import org.eclipse.jgit.errors.ConfigInvalidException;
 
 @Singleton
-public class AddSshKey implements RestModifyView<AccountResource, SshKeyInput> {
+public class AddSshKey
+    implements RestCollectionView<AccountResource, AccountResource.SshKey, SshKeyInput> {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
   private final Provider<CurrentUser> self;
diff --git a/java/com/google/gerrit/server/restapi/account/Module.java b/java/com/google/gerrit/server/restapi/account/Module.java
index f37687f..be0924a 100644
--- a/java/com/google/gerrit/server/restapi/account/Module.java
+++ b/java/com/google/gerrit/server/restapi/account/Module.java
@@ -66,12 +66,12 @@
     put(EMAIL_KIND, "preferred").to(PutPreferred.class);
     put(ACCOUNT_KIND, "password.http").to(PutHttpPassword.class);
     delete(ACCOUNT_KIND, "password.http").to(PutHttpPassword.class);
-    child(ACCOUNT_KIND, "sshkeys").to(SshKeys.class);
-    post(ACCOUNT_KIND, "sshkeys").to(AddSshKey.class);
     get(ACCOUNT_KIND, "watched.projects").to(GetWatchedProjects.class);
     post(ACCOUNT_KIND, "watched.projects").to(PostWatchedProjects.class);
     post(ACCOUNT_KIND, "watched.projects:delete").to(DeleteWatchedProjects.class);
 
+    child(ACCOUNT_KIND, "sshkeys").to(SshKeys.class);
+    postOnCollection(SSH_KEY_KIND).to(AddSshKey.class);
     get(SSH_KEY_KIND).to(GetSshKey.class);
     delete(SSH_KEY_KIND).to(DeleteSshKey.class);
 
diff --git a/java/com/google/gerrit/server/restapi/change/Abandon.java b/java/com/google/gerrit/server/restapi/change/Abandon.java
index 7978990..c739e54 100644
--- a/java/com/google/gerrit/server/restapi/change/Abandon.java
+++ b/java/com/google/gerrit/server/restapi/change/Abandon.java
@@ -81,7 +81,7 @@
       throws RestApiException, UpdateException, OrmException, PermissionBackendException,
           IOException, ConfigInvalidException {
     // Not allowed to abandon if the current patch set is locked.
-    patchSetUtil.checkPatchSetNotLocked(rsrc.getNotes(), rsrc.getUser());
+    patchSetUtil.checkPatchSetNotLocked(rsrc.getNotes());
 
     rsrc.permissions().database(dbProvider).check(ChangePermission.ABANDON);
 
@@ -155,7 +155,7 @@
     }
 
     try {
-      if (patchSetUtil.isPatchSetLocked(rsrc.getNotes(), rsrc.getUser())) {
+      if (patchSetUtil.isPatchSetLocked(rsrc.getNotes())) {
         return description;
       }
     } catch (OrmException | IOException e) {
diff --git a/java/com/google/gerrit/server/restapi/change/ChangeEdits.java b/java/com/google/gerrit/server/restapi/change/ChangeEdits.java
index 826c792..efc2712 100644
--- a/java/com/google/gerrit/server/restapi/change/ChangeEdits.java
+++ b/java/com/google/gerrit/server/restapi/change/ChangeEdits.java
@@ -20,7 +20,6 @@
 import com.google.gerrit.extensions.common.Input;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AcceptsDelete;
-import com.google.gerrit.extensions.restapi.AcceptsPost;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.BinaryResult;
@@ -32,6 +31,7 @@
 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.RestCollectionView;
 import com.google.gerrit.extensions.restapi.RestCreateView;
 import com.google.gerrit.extensions.restapi.RestModifyView;
 import com.google.gerrit.extensions.restapi.RestReadView;
@@ -71,26 +71,21 @@
 
 @Singleton
 public class ChangeEdits
-    implements ChildCollection<ChangeResource, ChangeEditResource>,
-        AcceptsPost<ChangeResource>,
-        AcceptsDelete<ChangeResource> {
+    implements ChildCollection<ChangeResource, ChangeEditResource>, AcceptsDelete<ChangeResource> {
   private final DynamicMap<RestView<ChangeEditResource>> views;
   private final DeleteFile.Factory deleteFileFactory;
   private final Provider<Detail> detail;
   private final ChangeEditUtil editUtil;
-  private final Post post;
 
   @Inject
   ChangeEdits(
       DynamicMap<RestView<ChangeEditResource>> views,
       Provider<Detail> detail,
       ChangeEditUtil editUtil,
-      Post post,
       DeleteFile.Factory deleteFileFactory) {
     this.views = views;
     this.detail = detail;
     this.editUtil = editUtil;
-    this.post = post;
     this.deleteFileFactory = deleteFileFactory;
   }
 
@@ -114,11 +109,6 @@
     return new ChangeEditResource(rsrc, edit.get(), id.get());
   }
 
-  @Override
-  public Post post(ChangeResource parent) throws RestApiException {
-    return post;
-  }
-
   /**
    * This method is invoked if a DELETE request on a non-existing member is done. For change edits
    * this is the case if a DELETE request for a file in a change edit is done and the change edit
@@ -247,7 +237,8 @@
    * The combination of two operations in one request is supported.
    */
   @Singleton
-  public static class Post implements RestModifyView<ChangeResource, Post.Input> {
+  public static class Post
+      implements RestCollectionView<ChangeResource, ChangeEditResource, Post.Input> {
     public static class Input {
       public String restorePath;
       public String oldPath;
diff --git a/java/com/google/gerrit/server/restapi/change/ChangesCollection.java b/java/com/google/gerrit/server/restapi/change/ChangesCollection.java
index 58ea185..e9b4d87 100644
--- a/java/com/google/gerrit/server/restapi/change/ChangesCollection.java
+++ b/java/com/google/gerrit/server/restapi/change/ChangesCollection.java
@@ -15,7 +15,6 @@
 package com.google.gerrit.server.restapi.change;
 
 import com.google.gerrit.extensions.registration.DynamicMap;
-import com.google.gerrit.extensions.restapi.AcceptsPost;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
@@ -43,14 +42,12 @@
 import java.util.List;
 
 @Singleton
-public class ChangesCollection
-    implements RestCollection<TopLevelResource, ChangeResource>, AcceptsPost<TopLevelResource> {
+public class ChangesCollection implements RestCollection<TopLevelResource, ChangeResource> {
   private final Provider<ReviewDb> db;
   private final Provider<CurrentUser> user;
   private final Provider<QueryChanges> queryFactory;
   private final DynamicMap<RestView<ChangeResource>> views;
   private final ChangeFinder changeFinder;
-  private final CreateChange createChange;
   private final ChangeResource.Factory changeResourceFactory;
   private final PermissionBackend permissionBackend;
   private final ProjectCache projectCache;
@@ -62,7 +59,6 @@
       Provider<QueryChanges> queryFactory,
       DynamicMap<RestView<ChangeResource>> views,
       ChangeFinder changeFinder,
-      CreateChange createChange,
       ChangeResource.Factory changeResourceFactory,
       PermissionBackend permissionBackend,
       ProjectCache projectCache) {
@@ -71,7 +67,6 @@
     this.queryFactory = queryFactory;
     this.views = views;
     this.changeFinder = changeFinder;
-    this.createChange = createChange;
     this.changeResourceFactory = changeResourceFactory;
     this.permissionBackend = permissionBackend;
     this.projectCache = projectCache;
@@ -130,11 +125,6 @@
     return changeResourceFactory.create(notes, user);
   }
 
-  @Override
-  public CreateChange post(TopLevelResource parent) throws RestApiException {
-    return createChange;
-  }
-
   private boolean canRead(ChangeNotes notes) throws PermissionBackendException, IOException {
     try {
       permissionBackend.currentUser().change(notes).database(db).check(ChangePermission.READ);
diff --git a/java/com/google/gerrit/server/restapi/change/CreateChange.java b/java/com/google/gerrit/server/restapi/change/CreateChange.java
index 73669a1..0dcbeb0 100644
--- a/java/com/google/gerrit/server/restapi/change/CreateChange.java
+++ b/java/com/google/gerrit/server/restapi/change/CreateChange.java
@@ -50,6 +50,7 @@
 import com.google.gerrit.server.account.AccountState;
 import com.google.gerrit.server.change.ChangeInserter;
 import com.google.gerrit.server.change.ChangeJson;
+import com.google.gerrit.server.change.ChangeResource;
 import com.google.gerrit.server.change.NotifyUtil;
 import com.google.gerrit.server.config.AnonymousCowardName;
 import com.google.gerrit.server.config.GerritServerConfig;
@@ -68,7 +69,7 @@
 import com.google.gerrit.server.restapi.project.ProjectsCollection;
 import com.google.gerrit.server.update.BatchUpdate;
 import com.google.gerrit.server.update.RetryHelper;
-import com.google.gerrit.server.update.RetryingRestModifyView;
+import com.google.gerrit.server.update.RetryingRestCollectionView;
 import com.google.gerrit.server.update.UpdateException;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
@@ -97,7 +98,8 @@
 
 @Singleton
 public class CreateChange
-    extends RetryingRestModifyView<TopLevelResource, ChangeInput, Response<ChangeInfo>> {
+    extends RetryingRestCollectionView<
+        TopLevelResource, ChangeResource, ChangeInput, Response<ChangeInfo>> {
   private final String anonymousCowardName;
   private final Provider<ReviewDb> db;
   private final GitRepositoryManager gitManager;
diff --git a/java/com/google/gerrit/server/restapi/change/CreateMergePatchSet.java b/java/com/google/gerrit/server/restapi/change/CreateMergePatchSet.java
index ff85880..a5698b6 100644
--- a/java/com/google/gerrit/server/restapi/change/CreateMergePatchSet.java
+++ b/java/com/google/gerrit/server/restapi/change/CreateMergePatchSet.java
@@ -128,7 +128,7 @@
       throws OrmException, IOException, RestApiException, UpdateException,
           PermissionBackendException {
     // Not allowed to create a new patch set if the current patch set is locked.
-    psUtil.checkPatchSetNotLocked(rsrc.getNotes(), rsrc.getUser());
+    psUtil.checkPatchSetNotLocked(rsrc.getNotes());
 
     rsrc.permissions().database(db).check(ChangePermission.ADD_PATCH_SET);
 
diff --git a/java/com/google/gerrit/server/restapi/change/DeleteReviewerOp.java b/java/com/google/gerrit/server/restapi/change/DeleteReviewerOp.java
index 91f5d15..2cc4ce4 100644
--- a/java/com/google/gerrit/server/restapi/change/DeleteReviewerOp.java
+++ b/java/com/google/gerrit/server/restapi/change/DeleteReviewerOp.java
@@ -131,8 +131,7 @@
     currChange = ctx.getChange();
     currPs = psUtil.current(ctx.getDb(), ctx.getNotes());
 
-    LabelTypes labelTypes =
-        projectCache.checkedGet(ctx.getProject()).getLabelTypes(ctx.getNotes(), ctx.getUser());
+    LabelTypes labelTypes = projectCache.checkedGet(ctx.getProject()).getLabelTypes(ctx.getNotes());
     // removing a reviewer will remove all her votes
     for (LabelType lt : labelTypes.getLabelTypes()) {
       newApprovals.put(lt.getName(), (short) 0);
diff --git a/java/com/google/gerrit/server/restapi/change/DeleteVote.java b/java/com/google/gerrit/server/restapi/change/DeleteVote.java
index f268a30..dc44e65 100644
--- a/java/com/google/gerrit/server/restapi/change/DeleteVote.java
+++ b/java/com/google/gerrit/server/restapi/change/DeleteVote.java
@@ -172,7 +172,7 @@
       ps = psUtil.current(db.get(), ctx.getNotes());
 
       boolean found = false;
-      LabelTypes labelTypes = projectState.getLabelTypes(ctx.getNotes(), ctx.getUser());
+      LabelTypes labelTypes = projectState.getLabelTypes(ctx.getNotes());
 
       Account.Id accountId = accountState.getAccount().getId();
 
@@ -180,7 +180,6 @@
           approvalsUtil.byPatchSetUser(
               ctx.getDb(),
               ctx.getNotes(),
-              ctx.getUser(),
               psId,
               accountId,
               ctx.getRevWalk(),
diff --git a/java/com/google/gerrit/server/restapi/change/Module.java b/java/com/google/gerrit/server/restapi/change/Module.java
index ef0ba2d..dca64fd 100644
--- a/java/com/google/gerrit/server/restapi/change/Module.java
+++ b/java/com/google/gerrit/server/restapi/change/Module.java
@@ -72,6 +72,7 @@
     DynamicMap.mapOf(binder(), VOTE_KIND);
     DynamicMap.mapOf(binder(), CHANGE_MESSAGE_KIND);
 
+    postOnCollection(CHANGE_KIND).to(CreateChange.class);
     get(CHANGE_KIND).to(GetChange.class);
     post(CHANGE_KIND, "merge").to(CreateMergePatchSet.class);
     get(CHANGE_KIND, "detail").to(GetDetail.class);
@@ -112,9 +113,9 @@
     post(CHANGE_KIND, "ready").to(SetReadyForReview.class);
     put(CHANGE_KIND, "message").to(PutMessage.class);
 
-    post(CHANGE_KIND, "reviewers").to(PostReviewers.class);
     get(CHANGE_KIND, "suggest_reviewers").to(SuggestChangeReviewers.class);
     child(CHANGE_KIND, "reviewers").to(Reviewers.class);
+    postOnCollection(REVIEWER_KIND).to(PostReviewers.class);
     get(REVIEWER_KIND).to(GetReviewer.class);
     delete(REVIEWER_KIND).to(DeleteReviewer.class);
     post(REVIEWER_KIND, "delete").to(DeleteReviewer.class);
@@ -170,9 +171,12 @@
 
     child(CHANGE_KIND, "edit").to(ChangeEdits.class);
     create(CHANGE_EDIT_KIND).to(ChangeEdits.Create.class);
+    postOnCollection(CHANGE_EDIT_KIND).to(ChangeEdits.Post.class);
     delete(CHANGE_KIND, "edit").to(DeleteChangeEdit.class);
     child(CHANGE_KIND, "edit:publish").to(PublishChangeEdit.class);
+    postOnCollection(CHANGE_EDIT_PUBLISH_KIND).to(PublishChangeEdit.Publish.class);
     child(CHANGE_KIND, "edit:rebase").to(RebaseChangeEdit.class);
+    postOnCollection(CHANGE_EDIT_REBASE_KIND).to(RebaseChangeEdit.Rebase.class);
     put(CHANGE_KIND, "edit:message").to(ChangeEdits.EditMessage.class);
     get(CHANGE_KIND, "edit:message").to(ChangeEdits.GetMessage.class);
     put(CHANGE_EDIT_KIND, "/").to(ChangeEdits.Put.class);
diff --git a/java/com/google/gerrit/server/restapi/change/Move.java b/java/com/google/gerrit/server/restapi/change/Move.java
index 42531c5..3833050 100644
--- a/java/com/google/gerrit/server/restapi/change/Move.java
+++ b/java/com/google/gerrit/server/restapi/change/Move.java
@@ -44,7 +44,6 @@
 import com.google.gerrit.server.ApprovalsUtil;
 import com.google.gerrit.server.ChangeMessagesUtil;
 import com.google.gerrit.server.ChangeUtil;
-import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.PatchSetUtil;
 import com.google.gerrit.server.change.ChangeJson;
@@ -88,7 +87,6 @@
   private final PatchSetUtil psUtil;
   private final ApprovalsUtil approvalsUtil;
   private final ProjectCache projectCache;
-  private final Provider<CurrentUser> userProvider;
 
   @Inject
   Move(
@@ -101,8 +99,7 @@
       RetryHelper retryHelper,
       PatchSetUtil psUtil,
       ApprovalsUtil approvalsUtil,
-      ProjectCache projectCache,
-      Provider<CurrentUser> userProvider) {
+      ProjectCache projectCache) {
     super(retryHelper);
     this.permissionBackend = permissionBackend;
     this.dbProvider = dbProvider;
@@ -113,7 +110,6 @@
     this.psUtil = psUtil;
     this.approvalsUtil = approvalsUtil;
     this.projectCache = projectCache;
-    this.userProvider = userProvider;
   }
 
   @Override
@@ -139,7 +135,7 @@
     }
 
     // Not allowed to move if the current patch set is locked.
-    psUtil.checkPatchSetNotLocked(rsrc.getNotes(), rsrc.getUser());
+    psUtil.checkPatchSetNotLocked(rsrc.getNotes());
 
     // Move requires abandoning this change, and creating a new change.
     try {
@@ -261,15 +257,9 @@
       List<PatchSetApproval> approvals = new ArrayList<>();
       for (PatchSetApproval psa :
           approvalsUtil.byPatchSet(
-              ctx.getDb(),
-              ctx.getNotes(),
-              userProvider.get(),
-              psId,
-              ctx.getRevWalk(),
-              ctx.getRepoView().getConfig())) {
+              ctx.getDb(), ctx.getNotes(), psId, ctx.getRevWalk(), ctx.getRepoView().getConfig())) {
         ProjectState projectState = projectCache.checkedGet(project);
-        LabelType type =
-            projectState.getLabelTypes(ctx.getNotes(), ctx.getUser()).byLabel(psa.getLabelId());
+        LabelType type = projectState.getLabelTypes(ctx.getNotes()).byLabel(psa.getLabelId());
         // Only keep veto votes, defined as votes where:
         // 1- the label function allows minimum values to block submission.
         // 2- the vote holds the minimum value.
@@ -314,7 +304,7 @@
     }
 
     try {
-      if (psUtil.isPatchSetLocked(rsrc.getNotes(), rsrc.getUser())) {
+      if (psUtil.isPatchSetLocked(rsrc.getNotes())) {
         return description;
       }
     } catch (OrmException | IOException e) {
diff --git a/java/com/google/gerrit/server/restapi/change/PostReview.java b/java/com/google/gerrit/server/restapi/change/PostReview.java
index e6f4f69..c6dbda3 100644
--- a/java/com/google/gerrit/server/restapi/change/PostReview.java
+++ b/java/com/google/gerrit/server/restapi/change/PostReview.java
@@ -237,7 +237,7 @@
       throw new ResourceConflictException("cannot post review on edit");
     }
     ProjectState projectState = projectCache.checkedGet(revision.getProject());
-    LabelTypes labelTypes = projectState.getLabelTypes(revision.getNotes(), revision.getUser());
+    LabelTypes labelTypes = projectState.getLabelTypes(revision.getNotes());
     input.drafts = firstNonNull(input.drafts, DraftHandling.KEEP);
     if (input.onBehalfOf != null) {
       revision = onBehalfOf(revision, labelTypes, input);
@@ -1148,7 +1148,7 @@
       List<PatchSetApproval> del = new ArrayList<>();
       List<PatchSetApproval> ups = new ArrayList<>();
       Map<String, PatchSetApproval> current = scanLabels(projectState, ctx, del);
-      LabelTypes labelTypes = projectState.getLabelTypes(ctx.getNotes(), ctx.getUser());
+      LabelTypes labelTypes = projectState.getLabelTypes(ctx.getNotes());
       Map<String, Short> allApprovals =
           getAllApprovals(labelTypes, approvalsByKey(current.values()), inLabels);
       Map<String, Short> previous =
@@ -1297,11 +1297,7 @@
           // If no existing label is being set to 0, hack in the caller
           // as a reviewer by picking the first server-wide LabelType.
           LabelId labelId =
-              projectState
-                  .getLabelTypes(ctx.getNotes(), ctx.getUser())
-                  .getLabelTypes()
-                  .get(0)
-                  .getLabelId();
+              projectState.getLabelTypes(ctx.getNotes()).getLabelTypes().get(0).getLabelId();
           PatchSetApproval c = ApprovalsUtil.newApproval(psId, user, labelId, 0, ctx.getWhen());
           c.setTag(in.tag);
           c.setGranted(ctx.getWhen());
@@ -1322,14 +1318,13 @@
     private Map<String, PatchSetApproval> scanLabels(
         ProjectState projectState, ChangeContext ctx, List<PatchSetApproval> del)
         throws OrmException, IOException {
-      LabelTypes labelTypes = projectState.getLabelTypes(ctx.getNotes(), ctx.getUser());
+      LabelTypes labelTypes = projectState.getLabelTypes(ctx.getNotes());
       Map<String, PatchSetApproval> current = new HashMap<>();
 
       for (PatchSetApproval a :
           approvalsUtil.byPatchSetUser(
               ctx.getDb(),
               ctx.getNotes(),
-              ctx.getUser(),
               psId,
               user.getAccountId(),
               ctx.getRevWalk(),
diff --git a/java/com/google/gerrit/server/restapi/change/PostReviewers.java b/java/com/google/gerrit/server/restapi/change/PostReviewers.java
index 65c7db7..4991c18 100644
--- a/java/com/google/gerrit/server/restapi/change/PostReviewers.java
+++ b/java/com/google/gerrit/server/restapi/change/PostReviewers.java
@@ -51,6 +51,7 @@
 import com.google.gerrit.server.change.ChangeMessages;
 import com.google.gerrit.server.change.ChangeResource;
 import com.google.gerrit.server.change.NotifyUtil;
+import com.google.gerrit.server.change.ReviewerResource;
 import com.google.gerrit.server.change.RevisionResource;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.group.SystemGroupBackend;
@@ -69,7 +70,7 @@
 import com.google.gerrit.server.restapi.group.GroupsCollection;
 import com.google.gerrit.server.update.BatchUpdate;
 import com.google.gerrit.server.update.RetryHelper;
-import com.google.gerrit.server.update.RetryingRestModifyView;
+import com.google.gerrit.server.update.RetryingRestCollectionView;
 import com.google.gerrit.server.update.UpdateException;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
@@ -85,7 +86,8 @@
 
 @Singleton
 public class PostReviewers
-    extends RetryingRestModifyView<ChangeResource, AddReviewerInput, AddReviewerResult> {
+    extends RetryingRestCollectionView<
+        ChangeResource, ReviewerResource, AddReviewerInput, AddReviewerResult> {
 
   public static final int DEFAULT_MAX_REVIEWERS_WITHOUT_CHECK = 10;
   public static final int DEFAULT_MAX_REVIEWERS = 20;
@@ -452,17 +454,13 @@
       }
 
       ChangeData cd = changeDataFactory.create(dbProvider.get(), notes);
-      PermissionBackend.ForChange perm =
-          permissionBackend.user(caller).database(dbProvider).change(cd);
-
       // Generate result details and fill AccountLoader. This occurs outside
       // the Op because the accounts are in a different table.
       PostReviewersOp.Result opResult = op.getResult();
       if (migration.readChanges() && state == CC) {
         result.ccs = Lists.newArrayListWithCapacity(opResult.addedCCs().size());
         for (Account.Id accountId : opResult.addedCCs()) {
-          result.ccs.add(
-              json.format(new ReviewerInfo(accountId.get()), perm.absentUser(accountId), cd));
+          result.ccs.add(json.format(new ReviewerInfo(accountId.get()), accountId, cd));
         }
         accountLoaderFactory.create(true).fill(result.ccs);
         for (Address a : reviewersByEmail) {
@@ -475,7 +473,7 @@
           result.reviewers.add(
               json.format(
                   new ReviewerInfo(psa.getAccountId().get()),
-                  perm.absentUser(psa.getAccountId()),
+                  psa.getAccountId(),
                   cd,
                   ImmutableList.of(psa)));
         }
diff --git a/java/com/google/gerrit/server/restapi/change/PostReviewersOp.java b/java/com/google/gerrit/server/restapi/change/PostReviewersOp.java
index 0502e91..3cb6136 100644
--- a/java/com/google/gerrit/server/restapi/change/PostReviewersOp.java
+++ b/java/com/google/gerrit/server/restapi/change/PostReviewersOp.java
@@ -169,7 +169,7 @@
                 ctx.getUpdate(ctx.getChange().currentPatchSetId()),
                 projectCache
                     .checkedGet(rsrc.getProject())
-                    .getLabelTypes(rsrc.getChange().getDest(), ctx.getUser()),
+                    .getLabelTypes(rsrc.getChange().getDest()),
                 rsrc.getChange(),
                 reviewers);
         if (addedReviewers.isEmpty()) {
diff --git a/java/com/google/gerrit/server/restapi/change/PublishChangeEdit.java b/java/com/google/gerrit/server/restapi/change/PublishChangeEdit.java
index 36a0561..7f4844e 100644
--- a/java/com/google/gerrit/server/restapi/change/PublishChangeEdit.java
+++ b/java/com/google/gerrit/server/restapi/change/PublishChangeEdit.java
@@ -16,7 +16,6 @@
 
 import com.google.gerrit.extensions.api.changes.PublishChangeEditInput;
 import com.google.gerrit.extensions.registration.DynamicMap;
-import com.google.gerrit.extensions.restapi.AcceptsPost;
 import com.google.gerrit.extensions.restapi.ChildCollection;
 import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
@@ -33,7 +32,7 @@
 import com.google.gerrit.server.project.NoSuchProjectException;
 import com.google.gerrit.server.update.BatchUpdate;
 import com.google.gerrit.server.update.RetryHelper;
-import com.google.gerrit.server.update.RetryingRestModifyView;
+import com.google.gerrit.server.update.RetryingRestCollectionView;
 import com.google.gerrit.server.update.UpdateException;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
@@ -44,16 +43,13 @@
 
 @Singleton
 public class PublishChangeEdit
-    implements ChildCollection<ChangeResource, ChangeEditResource.Publish>,
-        AcceptsPost<ChangeResource> {
+    implements ChildCollection<ChangeResource, ChangeEditResource.Publish> {
 
   private final DynamicMap<RestView<ChangeEditResource.Publish>> views;
-  private final Publish publish;
 
   @Inject
-  PublishChangeEdit(DynamicMap<RestView<ChangeEditResource.Publish>> views, Publish publish) {
+  PublishChangeEdit(DynamicMap<RestView<ChangeEditResource.Publish>> views) {
     this.views = views;
-    this.publish = publish;
   }
 
   @Override
@@ -72,14 +68,10 @@
     throw new ResourceNotFoundException();
   }
 
-  @Override
-  public Publish post(ChangeResource parent) throws RestApiException {
-    return publish;
-  }
-
   @Singleton
   public static class Publish
-      extends RetryingRestModifyView<ChangeResource, PublishChangeEditInput, Response<?>> {
+      extends RetryingRestCollectionView<
+          ChangeResource, ChangeEditResource.Publish, PublishChangeEditInput, Response<?>> {
 
     private final ChangeEditUtil editUtil;
     private final NotifyUtil notifyUtil;
diff --git a/java/com/google/gerrit/server/restapi/change/PutMessage.java b/java/com/google/gerrit/server/restapi/change/PutMessage.java
index eb46521..bee0ed7 100644
--- a/java/com/google/gerrit/server/restapi/change/PutMessage.java
+++ b/java/com/google/gerrit/server/restapi/change/PutMessage.java
@@ -184,7 +184,7 @@
     }
 
     // Not allowed to put message if the current patch set is locked.
-    psUtil.checkPatchSetNotLocked(changeNotes, userProvider.get());
+    psUtil.checkPatchSetNotLocked(changeNotes);
     try {
       permissionBackend
           .user(userProvider.get())
diff --git a/java/com/google/gerrit/server/restapi/change/Rebase.java b/java/com/google/gerrit/server/restapi/change/Rebase.java
index 99a755ae..0fffb58 100644
--- a/java/com/google/gerrit/server/restapi/change/Rebase.java
+++ b/java/com/google/gerrit/server/restapi/change/Rebase.java
@@ -107,7 +107,7 @@
       throws OrmException, UpdateException, RestApiException, IOException,
           PermissionBackendException {
     // Not allowed to rebase if the current patch set is locked.
-    patchSetUtil.checkPatchSetNotLocked(rsrc.getNotes(), rsrc.getUser());
+    patchSetUtil.checkPatchSetNotLocked(rsrc.getNotes());
 
     rsrc.permissions().database(dbProvider).check(ChangePermission.REBASE);
     projectCache.checkedGet(rsrc.getProject()).checkStatePermitsWrite();
@@ -228,7 +228,7 @@
     }
 
     try {
-      if (patchSetUtil.isPatchSetLocked(rsrc.getNotes(), rsrc.getUser())) {
+      if (patchSetUtil.isPatchSetLocked(rsrc.getNotes())) {
         return description;
       }
     } catch (OrmException | IOException e) {
diff --git a/java/com/google/gerrit/server/restapi/change/RebaseChangeEdit.java b/java/com/google/gerrit/server/restapi/change/RebaseChangeEdit.java
index 47af894..8868e0e 100644
--- a/java/com/google/gerrit/server/restapi/change/RebaseChangeEdit.java
+++ b/java/com/google/gerrit/server/restapi/change/RebaseChangeEdit.java
@@ -16,14 +16,12 @@
 
 import com.google.gerrit.extensions.common.Input;
 import com.google.gerrit.extensions.registration.DynamicMap;
-import com.google.gerrit.extensions.restapi.AcceptsPost;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.ChildCollection;
 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.RestView;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.change.ChangeEditResource;
@@ -34,7 +32,7 @@
 import com.google.gerrit.server.project.InvalidChangeOperationException;
 import com.google.gerrit.server.update.BatchUpdate;
 import com.google.gerrit.server.update.RetryHelper;
-import com.google.gerrit.server.update.RetryingRestModifyView;
+import com.google.gerrit.server.update.RetryingRestCollectionView;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
@@ -43,16 +41,13 @@
 
 @Singleton
 public class RebaseChangeEdit
-    implements ChildCollection<ChangeResource, ChangeEditResource.Rebase>,
-        AcceptsPost<ChangeResource> {
+    implements ChildCollection<ChangeResource, ChangeEditResource.Rebase> {
 
   private final DynamicMap<RestView<ChangeEditResource.Rebase>> views;
-  private final Rebase rebase;
 
   @Inject
-  RebaseChangeEdit(DynamicMap<RestView<ChangeEditResource.Rebase>> views, Rebase rebase) {
+  RebaseChangeEdit(DynamicMap<RestView<ChangeEditResource.Rebase>> views) {
     this.views = views;
-    this.rebase = rebase;
   }
 
   @Override
@@ -71,13 +66,10 @@
     throw new ResourceNotFoundException();
   }
 
-  @Override
-  public Rebase post(ChangeResource parent) throws RestApiException {
-    return rebase;
-  }
-
   @Singleton
-  public static class Rebase extends RetryingRestModifyView<ChangeResource, Input, Response<?>> {
+  public static class Rebase
+      extends RetryingRestCollectionView<
+          ChangeResource, ChangeEditResource.Rebase, Input, Response<?>> {
     private final GitRepositoryManager repositoryManager;
     private final ChangeEditModifier editModifier;
 
diff --git a/java/com/google/gerrit/server/restapi/change/Restore.java b/java/com/google/gerrit/server/restapi/change/Restore.java
index 5e4ede3..a29347f 100644
--- a/java/com/google/gerrit/server/restapi/change/Restore.java
+++ b/java/com/google/gerrit/server/restapi/change/Restore.java
@@ -91,7 +91,7 @@
       throws RestApiException, UpdateException, OrmException, PermissionBackendException,
           IOException {
     // Not allowed to restore if the current patch set is locked.
-    psUtil.checkPatchSetNotLocked(rsrc.getNotes(), rsrc.getUser());
+    psUtil.checkPatchSetNotLocked(rsrc.getNotes());
 
     rsrc.permissions().database(dbProvider).check(ChangePermission.RESTORE);
     projectCache.checkedGet(rsrc.getProject()).checkStatePermitsWrite();
@@ -183,7 +183,7 @@
     }
 
     try {
-      if (psUtil.isPatchSetLocked(rsrc.getNotes(), rsrc.getUser())) {
+      if (psUtil.isPatchSetLocked(rsrc.getNotes())) {
         return description;
       }
     } catch (OrmException | IOException e) {
diff --git a/java/com/google/gerrit/server/restapi/change/ReviewerJson.java b/java/com/google/gerrit/server/restapi/change/ReviewerJson.java
index cfd20c2..c891a65 100644
--- a/java/com/google/gerrit/server/restapi/change/ReviewerJson.java
+++ b/java/com/google/gerrit/server/restapi/change/ReviewerJson.java
@@ -80,10 +80,7 @@
       ReviewerInfo info =
           format(
               new ReviewerInfo(rsrc.getReviewerUser().getAccountId().get()),
-              permissionBackend
-                  .absentUser(rsrc.getReviewerUser().getAccountId())
-                  .database(db)
-                  .change(cd),
+              rsrc.getReviewerUser().getAccountId(),
               cd);
       loader.put(info);
       infos.add(info);
@@ -97,22 +94,19 @@
     return format(ImmutableList.<ReviewerResource>of(rsrc));
   }
 
-  public ReviewerInfo format(ReviewerInfo out, PermissionBackend.ForChange perm, ChangeData cd)
+  public ReviewerInfo format(ReviewerInfo out, Account.Id reviewer, ChangeData cd)
       throws OrmException, PermissionBackendException {
     PatchSet.Id psId = cd.change().currentPatchSetId();
     return format(
         out,
-        perm,
+        reviewer,
         cd,
         approvalsUtil.byPatchSetUser(
-            db.get(), cd.notes(), perm.user(), psId, new Account.Id(out._accountId), null, null));
+            db.get(), cd.notes(), psId, new Account.Id(out._accountId), null, null));
   }
 
   public ReviewerInfo format(
-      ReviewerInfo out,
-      PermissionBackend.ForChange perm,
-      ChangeData cd,
-      Iterable<PatchSetApproval> approvals)
+      ReviewerInfo out, Account.Id reviewer, ChangeData cd, Iterable<PatchSetApproval> approvals)
       throws OrmException, PermissionBackendException {
     LabelTypes labelTypes = cd.getLabelTypes();
 
@@ -128,6 +122,9 @@
     // do not exist in the DB.
     PatchSet ps = cd.currentPatchSet();
     if (ps != null) {
+      PermissionBackend.ForChange perm =
+          permissionBackend.absentUser(reviewer).database(db).change(cd);
+
       for (SubmitRecord rec : submitRuleEvaluator.evaluate(cd)) {
         if (rec.labels == null) {
           continue;
diff --git a/java/com/google/gerrit/server/restapi/change/Votes.java b/java/com/google/gerrit/server/restapi/change/Votes.java
index b931c7e..3b2548c 100644
--- a/java/com/google/gerrit/server/restapi/change/Votes.java
+++ b/java/com/google/gerrit/server/restapi/change/Votes.java
@@ -87,7 +87,6 @@
           approvalsUtil.byPatchSetUser(
               db.get(),
               rsrc.getChangeResource().getNotes(),
-              rsrc.getChangeResource().getUser(),
               rsrc.getChange().currentPatchSetId(),
               rsrc.getReviewerUser().getAccountId(),
               null,
diff --git a/java/com/google/gerrit/server/restapi/config/CachesCollection.java b/java/com/google/gerrit/server/restapi/config/CachesCollection.java
index e3d9e3c..152fef9 100644
--- a/java/com/google/gerrit/server/restapi/config/CachesCollection.java
+++ b/java/com/google/gerrit/server/restapi/config/CachesCollection.java
@@ -20,12 +20,10 @@
 import com.google.common.cache.Cache;
 import com.google.gerrit.extensions.annotations.RequiresAnyCapability;
 import com.google.gerrit.extensions.registration.DynamicMap;
-import com.google.gerrit.extensions.restapi.AcceptsPost;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.ChildCollection;
 import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
-import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestView;
 import com.google.gerrit.server.config.CacheResource;
 import com.google.gerrit.server.config.ConfigResource;
@@ -38,27 +36,23 @@
 
 @RequiresAnyCapability({VIEW_CACHES, MAINTAIN_SERVER})
 @Singleton
-public class CachesCollection
-    implements ChildCollection<ConfigResource, CacheResource>, AcceptsPost<ConfigResource> {
+public class CachesCollection implements ChildCollection<ConfigResource, CacheResource> {
 
   private final DynamicMap<RestView<CacheResource>> views;
   private final Provider<ListCaches> list;
   private final PermissionBackend permissionBackend;
   private final DynamicMap<Cache<?, ?>> cacheMap;
-  private final PostCaches postCaches;
 
   @Inject
   CachesCollection(
       DynamicMap<RestView<CacheResource>> views,
       Provider<ListCaches> list,
       PermissionBackend permissionBackend,
-      DynamicMap<Cache<?, ?>> cacheMap,
-      PostCaches postCaches) {
+      DynamicMap<Cache<?, ?>> cacheMap) {
     this.views = views;
     this.list = list;
     this.permissionBackend = permissionBackend;
     this.cacheMap = cacheMap;
-    this.postCaches = postCaches;
   }
 
   @Override
@@ -90,9 +84,4 @@
   public DynamicMap<RestView<CacheResource>> views() {
     return views;
   }
-
-  @Override
-  public PostCaches post(ConfigResource parent) throws RestApiException {
-    return postCaches;
-  }
 }
diff --git a/java/com/google/gerrit/server/restapi/config/PostCaches.java b/java/com/google/gerrit/server/restapi/config/PostCaches.java
index f21672c..e20e477 100644
--- a/java/com/google/gerrit/server/restapi/config/PostCaches.java
+++ b/java/com/google/gerrit/server/restapi/config/PostCaches.java
@@ -23,7 +23,7 @@
 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.RestModifyView;
+import com.google.gerrit.extensions.restapi.RestCollectionView;
 import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
 import com.google.gerrit.server.config.CacheResource;
 import com.google.gerrit.server.config.ConfigResource;
@@ -36,7 +36,7 @@
 
 @RequiresAnyCapability({FLUSH_CACHES, MAINTAIN_SERVER})
 @Singleton
-public class PostCaches implements RestModifyView<ConfigResource, Input> {
+public class PostCaches implements RestCollectionView<ConfigResource, CacheResource, Input> {
   public static class Input {
     public Operation operation;
     public List<String> caches;
diff --git a/java/com/google/gerrit/server/restapi/config/RestCacheAdminModule.java b/java/com/google/gerrit/server/restapi/config/RestCacheAdminModule.java
index 7283033..c929bc6 100644
--- a/java/com/google/gerrit/server/restapi/config/RestCacheAdminModule.java
+++ b/java/com/google/gerrit/server/restapi/config/RestCacheAdminModule.java
@@ -26,6 +26,7 @@
   protected void configure() {
     DynamicMap.mapOf(binder(), CACHE_KIND);
     child(CONFIG_KIND, "caches").to(CachesCollection.class);
+    postOnCollection(CACHE_KIND).to(PostCaches.class);
     get(CACHE_KIND).to(GetCache.class);
     post(CACHE_KIND, "flush").to(FlushCache.class);
     get(CONFIG_KIND, "summary").to(GetSummary.class);
diff --git a/java/com/google/gerrit/server/restapi/project/Index.java b/java/com/google/gerrit/server/restapi/project/Index.java
index 5547864..1b2a523 100644
--- a/java/com/google/gerrit/server/restapi/project/Index.java
+++ b/java/com/google/gerrit/server/restapi/project/Index.java
@@ -21,6 +21,7 @@
 import com.google.gerrit.common.data.GlobalCapability;
 import com.google.gerrit.extensions.annotations.RequiresCapability;
 import com.google.gerrit.extensions.api.projects.IndexProjectInput;
+import com.google.gerrit.extensions.common.ProjectInfo;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.Response;
@@ -62,27 +63,33 @@
           ResourceConflictException {
     String response = "Project " + rsrc.getName() + " submitted for reindexing";
 
-    reindexAsync(rsrc.getNameKey());
+    reindex(rsrc.getNameKey(), input.async);
     if (Boolean.TRUE.equals(input.indexChildren)) {
       ListChildProjects listChildProjects = listChildProjectsProvider.get();
       listChildProjects.setRecursive(true);
-      listChildProjects.apply(rsrc).forEach(p -> reindexAsync(new Project.NameKey(p.name)));
+      for (ProjectInfo child : listChildProjects.apply(rsrc)) {
+        reindex(new Project.NameKey(child.name), input.async);
+      }
 
       response += " (indexing children recursively)";
     }
     return Response.accepted(response);
   }
 
-  private void reindexAsync(Project.NameKey project) {
-    @SuppressWarnings("unused")
-    Future<?> possiblyIgnoredError =
-        executor.submit(
-            () -> {
-              try {
-                indexer.index(project);
-              } catch (IOException e) {
-                logger.atWarning().withCause(e).log("reindexing project %s failed", project);
-              }
-            });
+  private void reindex(Project.NameKey project, Boolean async) throws IOException {
+    if (Boolean.TRUE.equals(async)) {
+      @SuppressWarnings("unused")
+      Future<?> possiblyIgnoredError =
+          executor.submit(
+              () -> {
+                try {
+                  indexer.index(project);
+                } catch (IOException e) {
+                  logger.atWarning().withCause(e).log("reindexing project %s failed", project);
+                }
+              });
+    } else {
+      indexer.index(project);
+    }
   }
 }
diff --git a/java/com/google/gerrit/server/submit/MergeOp.java b/java/com/google/gerrit/server/submit/MergeOp.java
index a39e4e9..cb2e306 100644
--- a/java/com/google/gerrit/server/submit/MergeOp.java
+++ b/java/com/google/gerrit/server/submit/MergeOp.java
@@ -787,19 +787,33 @@
       }
 
       if (!revisions.containsEntry(id, ps.getId())) {
-        // TODO this is actually an error, the branch is gone but we
-        // want to merge the issue. We can't safely do that if the
-        // tip is not reachable.
-        //
+        if (revisions.containsValue(ps.getId())) {
+          // TODO This is actually an error, the patch set ref exists but points to a revision that
+          // is different from the revision that we have stored for the patch set in the change
+          // meta data.
+          commitStatus.logProblem(
+              changeId,
+              "Revision "
+                  + idstr
+                  + " of patch set "
+                  + ps.getPatchSetId()
+                  + " does not match the revision of the patch set ref "
+                  + ps.getId().toRefName());
+          continue;
+        }
+
+        // The patch set ref is not found but we want to merge the change. We can't safely do that
+        // if the patch set ref is missing. In a multi-master setup this can indicate a replication
+        // lag (e.g. the change meta data was already replicated, but the replication of the patch
+        // set ref is still pending).
         commitStatus.logProblem(
             changeId,
-            "Revision "
-                + idstr
-                + " of patch set "
-                + ps.getPatchSetId()
-                + " does not match "
+            "Patch set ref "
                 + ps.getId().toRefName()
-                + " for change");
+                + " not found. Expected patch set ref of "
+                + ps.getPatchSetId()
+                + " to point to revision "
+                + idstr);
         continue;
       }
 
diff --git a/java/com/google/gerrit/server/submit/SubmitStrategyOp.java b/java/com/google/gerrit/server/submit/SubmitStrategyOp.java
index 62dabae..abe3632 100644
--- a/java/com/google/gerrit/server/submit/SubmitStrategyOp.java
+++ b/java/com/google/gerrit/server/submit/SubmitStrategyOp.java
@@ -357,12 +357,7 @@
     Map<PatchSetApproval.Key, PatchSetApproval> byKey = new HashMap<>();
     for (PatchSetApproval psa :
         args.approvalsUtil.byPatchSet(
-            ctx.getDb(),
-            ctx.getNotes(),
-            ctx.getUser(),
-            psId,
-            ctx.getRevWalk(),
-            ctx.getRepoView().getConfig())) {
+            ctx.getDb(), ctx.getNotes(), psId, ctx.getRevWalk(), ctx.getRepoView().getConfig())) {
       byKey.put(psa.getKey(), psa);
     }
 
@@ -376,7 +371,7 @@
     // was added. So we need to make sure votes are accurate now. This way if
     // permissions get modified in the future, historical records stay accurate.
     LabelNormalizer.Result normalized =
-        args.labelNormalizer.normalize(ctx.getNotes(), ctx.getUser(), byKey.values());
+        args.labelNormalizer.normalize(ctx.getNotes(), byKey.values());
     update.putApproval(submitter.getLabel(), submitter.getValue());
     saveApprovals(normalized, ctx, update, false);
     return normalized;
diff --git a/java/com/google/gerrit/server/update/RetryingRestCollectionView.java b/java/com/google/gerrit/server/update/RetryingRestCollectionView.java
new file mode 100644
index 0000000..e0e3148
--- /dev/null
+++ b/java/com/google/gerrit/server/update/RetryingRestCollectionView.java
@@ -0,0 +1,40 @@
+// Copyright (C) 2018 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.update;
+
+import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.extensions.restapi.BadRequestException;
+import com.google.gerrit.extensions.restapi.ResourceConflictException;
+import com.google.gerrit.extensions.restapi.RestCollectionView;
+import com.google.gerrit.extensions.restapi.RestResource;
+
+public abstract class RetryingRestCollectionView<
+        P extends RestResource, C extends RestResource, I, O>
+    implements RestCollectionView<P, C, I> {
+  private final RetryHelper retryHelper;
+
+  protected RetryingRestCollectionView(RetryHelper retryHelper) {
+    this.retryHelper = retryHelper;
+  }
+
+  @Override
+  public final O apply(P parentResource, I input)
+      throws AuthException, BadRequestException, ResourceConflictException, Exception {
+    return retryHelper.execute((updateFactory) -> applyImpl(updateFactory, parentResource, input));
+  }
+
+  protected abstract O applyImpl(BatchUpdate.Factory updateFactory, P parentResource, I input)
+      throws Exception;
+}
diff --git a/javatests/com/google/gerrit/acceptance/api/accounts/AgreementsIT.java b/javatests/com/google/gerrit/acceptance/api/accounts/AgreementsIT.java
index c3a0dc9..7a4a901 100644
--- a/javatests/com/google/gerrit/acceptance/api/accounts/AgreementsIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/accounts/AgreementsIT.java
@@ -177,7 +177,7 @@
     setApiUser(user);
     setUseContributorAgreements(InheritableBoolean.TRUE);
     exception.expect(AuthException.class);
-    exception.expectMessage("A Contributor Agreement must be completed");
+    exception.expectMessage("Contributor Agreement");
     gApi.changes().id(change.changeId).revert();
   }
 
@@ -209,7 +209,7 @@
     in.destination = dest.ref;
     in.message = change.subject;
     exception.expect(AuthException.class);
-    exception.expectMessage("A Contributor Agreement must be completed");
+    exception.expectMessage("Contributor Agreement");
     gApi.changes().id(change.changeId).current().cherryPick(in);
   }
 
@@ -227,7 +227,7 @@
       gApi.changes().create(newChangeInput());
       fail("Expected AuthException");
     } catch (AuthException e) {
-      assertThat(e.getMessage()).contains("A Contributor Agreement must be completed");
+      assertThat(e.getMessage()).contains("Contributor Agreement");
     }
 
     // Sign the agreement
diff --git a/javatests/com/google/gerrit/common/data/PermissionRuleTest.java b/javatests/com/google/gerrit/common/data/PermissionRuleTest.java
new file mode 100644
index 0000000..14c47b4
--- /dev/null
+++ b/javatests/com/google/gerrit/common/data/PermissionRuleTest.java
@@ -0,0 +1,399 @@
+// Copyright (C) 2018 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.common.data;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.gerrit.common.data.PermissionRule.Action;
+import com.google.gerrit.reviewdb.client.AccountGroup;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+public class PermissionRuleTest {
+  @Rule public ExpectedException exception = ExpectedException.none();
+
+  private GroupReference groupReference;
+  private PermissionRule permissionRule;
+
+  @Before
+  public void setup() {
+    this.groupReference = new GroupReference(new AccountGroup.UUID("uuid"), "group");
+    this.permissionRule = new PermissionRule(groupReference);
+  }
+
+  @Test
+  public void getAndSetAction() {
+    assertThat(permissionRule.getAction()).isEqualTo(Action.ALLOW);
+
+    permissionRule.setAction(Action.DENY);
+    assertThat(permissionRule.getAction()).isEqualTo(Action.DENY);
+  }
+
+  @Test
+  public void cannotSetActionToNull() {
+    exception.expect(NullPointerException.class);
+    permissionRule.setAction(null);
+  }
+
+  @Test
+  public void setDeny() {
+    assertThat(permissionRule.isDeny()).isFalse();
+
+    permissionRule.setDeny();
+    assertThat(permissionRule.isDeny()).isTrue();
+  }
+
+  @Test
+  public void setBlock() {
+    assertThat(permissionRule.isBlock()).isFalse();
+
+    permissionRule.setBlock();
+    assertThat(permissionRule.isBlock()).isTrue();
+  }
+
+  @Test
+  public void setForce() {
+    assertThat(permissionRule.getForce()).isFalse();
+
+    permissionRule.setForce(true);
+    assertThat(permissionRule.getForce()).isTrue();
+
+    permissionRule.setForce(false);
+    assertThat(permissionRule.getForce()).isFalse();
+  }
+
+  @Test
+  public void setMin() {
+    assertThat(permissionRule.getMin()).isEqualTo(0);
+
+    permissionRule.setMin(-2);
+    assertThat(permissionRule.getMin()).isEqualTo(-2);
+
+    permissionRule.setMin(2);
+    assertThat(permissionRule.getMin()).isEqualTo(2);
+  }
+
+  @Test
+  public void setMax() {
+    assertThat(permissionRule.getMax()).isEqualTo(0);
+
+    permissionRule.setMax(2);
+    assertThat(permissionRule.getMax()).isEqualTo(2);
+
+    permissionRule.setMax(-2);
+    assertThat(permissionRule.getMax()).isEqualTo(-2);
+  }
+
+  @Test
+  public void setRange() {
+    assertThat(permissionRule.getMin()).isEqualTo(0);
+    assertThat(permissionRule.getMax()).isEqualTo(0);
+
+    permissionRule.setRange(-2, 2);
+    assertThat(permissionRule.getMin()).isEqualTo(-2);
+    assertThat(permissionRule.getMax()).isEqualTo(2);
+
+    permissionRule.setRange(2, -2);
+    assertThat(permissionRule.getMin()).isEqualTo(-2);
+    assertThat(permissionRule.getMax()).isEqualTo(2);
+
+    permissionRule.setRange(1, 1);
+    assertThat(permissionRule.getMin()).isEqualTo(1);
+    assertThat(permissionRule.getMax()).isEqualTo(1);
+  }
+
+  @Test
+  public void hasRange() {
+    assertThat(permissionRule.hasRange()).isFalse();
+
+    permissionRule.setMin(-1);
+    assertThat(permissionRule.hasRange()).isTrue();
+
+    permissionRule.setMax(1);
+    assertThat(permissionRule.hasRange()).isTrue();
+  }
+
+  @Test
+  public void getGroup() {
+    assertThat(permissionRule.getGroup()).isEqualTo(groupReference);
+  }
+
+  @Test
+  public void setGroup() {
+    GroupReference groupReference2 = new GroupReference(new AccountGroup.UUID("uuid2"), "group2");
+    assertThat(groupReference2).isNotEqualTo(groupReference);
+
+    assertThat(permissionRule.getGroup()).isEqualTo(groupReference);
+
+    permissionRule.setGroup(groupReference2);
+    assertThat(permissionRule.getGroup()).isEqualTo(groupReference2);
+  }
+
+  @Test
+  public void mergeFromAnyBlock() {
+    GroupReference groupReference1 = new GroupReference(new AccountGroup.UUID("uuid1"), "group1");
+    PermissionRule permissionRule1 = new PermissionRule(groupReference1);
+
+    GroupReference groupReference2 = new GroupReference(new AccountGroup.UUID("uuid2"), "group2");
+    PermissionRule permissionRule2 = new PermissionRule(groupReference2);
+
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.isBlock()).isFalse();
+    assertThat(permissionRule2.isBlock()).isFalse();
+
+    permissionRule2.setBlock();
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.isBlock()).isTrue();
+    assertThat(permissionRule2.isBlock()).isTrue();
+
+    permissionRule2.setDeny();
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.isBlock()).isTrue();
+    assertThat(permissionRule2.isBlock()).isFalse();
+
+    permissionRule2.setAction(Action.BATCH);
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.isBlock()).isTrue();
+    assertThat(permissionRule2.isBlock()).isFalse();
+  }
+
+  @Test
+  public void mergeFromAnyDeny() {
+    GroupReference groupReference1 = new GroupReference(new AccountGroup.UUID("uuid1"), "group1");
+    PermissionRule permissionRule1 = new PermissionRule(groupReference1);
+
+    GroupReference groupReference2 = new GroupReference(new AccountGroup.UUID("uuid2"), "group2");
+    PermissionRule permissionRule2 = new PermissionRule(groupReference2);
+
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.isDeny()).isFalse();
+    assertThat(permissionRule2.isDeny()).isFalse();
+
+    permissionRule2.setDeny();
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.isDeny()).isTrue();
+    assertThat(permissionRule2.isDeny()).isTrue();
+
+    permissionRule2.setAction(Action.BATCH);
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.isDeny()).isTrue();
+    assertThat(permissionRule2.isDeny()).isFalse();
+  }
+
+  @Test
+  public void mergeFromAnyBatch() {
+    GroupReference groupReference1 = new GroupReference(new AccountGroup.UUID("uuid1"), "group1");
+    PermissionRule permissionRule1 = new PermissionRule(groupReference1);
+
+    GroupReference groupReference2 = new GroupReference(new AccountGroup.UUID("uuid2"), "group2");
+    PermissionRule permissionRule2 = new PermissionRule(groupReference2);
+
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.getAction()).isNotEqualTo(Action.BATCH);
+    assertThat(permissionRule2.getAction()).isNotEqualTo(Action.BATCH);
+
+    permissionRule2.setAction(Action.BATCH);
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.getAction()).isEqualTo(Action.BATCH);
+    assertThat(permissionRule2.getAction()).isEqualTo(Action.BATCH);
+
+    permissionRule2.setAction(Action.ALLOW);
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.getAction()).isEqualTo(Action.BATCH);
+    assertThat(permissionRule2.getAction()).isNotEqualTo(Action.BATCH);
+  }
+
+  @Test
+  public void mergeFromAnyForce() {
+    GroupReference groupReference1 = new GroupReference(new AccountGroup.UUID("uuid1"), "group1");
+    PermissionRule permissionRule1 = new PermissionRule(groupReference1);
+
+    GroupReference groupReference2 = new GroupReference(new AccountGroup.UUID("uuid2"), "group2");
+    PermissionRule permissionRule2 = new PermissionRule(groupReference2);
+
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.getForce()).isFalse();
+    assertThat(permissionRule2.getForce()).isFalse();
+
+    permissionRule2.setForce(true);
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.getForce()).isTrue();
+    assertThat(permissionRule2.getForce()).isTrue();
+
+    permissionRule2.setForce(false);
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.getForce()).isTrue();
+    assertThat(permissionRule2.getForce()).isFalse();
+  }
+
+  @Test
+  public void mergeFromMergeRange() {
+    GroupReference groupReference1 = new GroupReference(new AccountGroup.UUID("uuid1"), "group1");
+    PermissionRule permissionRule1 = new PermissionRule(groupReference1);
+    permissionRule1.setRange(-1, 2);
+
+    GroupReference groupReference2 = new GroupReference(new AccountGroup.UUID("uuid2"), "group2");
+    PermissionRule permissionRule2 = new PermissionRule(groupReference2);
+    permissionRule2.setRange(-2, 1);
+
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.getMin()).isEqualTo(-2);
+    assertThat(permissionRule1.getMax()).isEqualTo(2);
+    assertThat(permissionRule2.getMin()).isEqualTo(-2);
+    assertThat(permissionRule2.getMax()).isEqualTo(1);
+  }
+
+  @Test
+  public void mergeFromGroupNotChanged() {
+    GroupReference groupReference1 = new GroupReference(new AccountGroup.UUID("uuid1"), "group1");
+    PermissionRule permissionRule1 = new PermissionRule(groupReference1);
+
+    GroupReference groupReference2 = new GroupReference(new AccountGroup.UUID("uuid2"), "group2");
+    PermissionRule permissionRule2 = new PermissionRule(groupReference2);
+
+    permissionRule1.mergeFrom(permissionRule2);
+    assertThat(permissionRule1.getGroup()).isEqualTo(groupReference1);
+    assertThat(permissionRule2.getGroup()).isEqualTo(groupReference2);
+  }
+
+  @Test
+  public void asString() {
+    assertThat(permissionRule.asString(true)).isEqualTo("group " + groupReference.getName());
+
+    permissionRule.setDeny();
+    assertThat(permissionRule.asString(true)).isEqualTo("deny group " + groupReference.getName());
+
+    permissionRule.setBlock();
+    assertThat(permissionRule.asString(true)).isEqualTo("block group " + groupReference.getName());
+
+    permissionRule.setAction(Action.BATCH);
+    assertThat(permissionRule.asString(true)).isEqualTo("batch group " + groupReference.getName());
+
+    permissionRule.setAction(Action.INTERACTIVE);
+    assertThat(permissionRule.asString(true))
+        .isEqualTo("interactive group " + groupReference.getName());
+
+    permissionRule.setForce(true);
+    assertThat(permissionRule.asString(true))
+        .isEqualTo("interactive +force group " + groupReference.getName());
+
+    permissionRule.setAction(Action.ALLOW);
+    assertThat(permissionRule.asString(true)).isEqualTo("+force group " + groupReference.getName());
+
+    permissionRule.setMax(1);
+    assertThat(permissionRule.asString(true))
+        .isEqualTo("+force +0..+1 group " + groupReference.getName());
+
+    permissionRule.setMin(-1);
+    assertThat(permissionRule.asString(true))
+        .isEqualTo("+force -1..+1 group " + groupReference.getName());
+
+    assertThat(permissionRule.asString(false))
+        .isEqualTo("+force group " + groupReference.getName());
+  }
+
+  @Test
+  public void fromString() {
+    PermissionRule permissionRule = PermissionRule.fromString("group A", true);
+    assertPermissionRule(permissionRule, "A", Action.ALLOW, false, 0, 0);
+
+    permissionRule = PermissionRule.fromString("deny group A", true);
+    assertPermissionRule(permissionRule, "A", Action.DENY, false, 0, 0);
+
+    permissionRule = PermissionRule.fromString("block group A", true);
+    assertPermissionRule(permissionRule, "A", Action.BLOCK, false, 0, 0);
+
+    permissionRule = PermissionRule.fromString("batch group A", true);
+    assertPermissionRule(permissionRule, "A", Action.BATCH, false, 0, 0);
+
+    permissionRule = PermissionRule.fromString("interactive group A", true);
+    assertPermissionRule(permissionRule, "A", Action.INTERACTIVE, false, 0, 0);
+
+    permissionRule = PermissionRule.fromString("interactive +force group A", true);
+    assertPermissionRule(permissionRule, "A", Action.INTERACTIVE, true, 0, 0);
+
+    permissionRule = PermissionRule.fromString("+force group A", true);
+    assertPermissionRule(permissionRule, "A", Action.ALLOW, true, 0, 0);
+
+    permissionRule = PermissionRule.fromString("+force +0..+1 group A", true);
+    assertPermissionRule(permissionRule, "A", Action.ALLOW, true, 0, 1);
+
+    permissionRule = PermissionRule.fromString("+force -1..+1 group A", true);
+    assertPermissionRule(permissionRule, "A", Action.ALLOW, true, -1, 1);
+
+    permissionRule = PermissionRule.fromString("+force group A", false);
+    assertPermissionRule(permissionRule, "A", Action.ALLOW, true, 0, 0);
+  }
+
+  @Test
+  public void parseInt() {
+    assertThat(PermissionRule.parseInt("0")).isEqualTo(0);
+    assertThat(PermissionRule.parseInt("+0")).isEqualTo(0);
+    assertThat(PermissionRule.parseInt("-0")).isEqualTo(0);
+    assertThat(PermissionRule.parseInt("1")).isEqualTo(1);
+    assertThat(PermissionRule.parseInt("+1")).isEqualTo(1);
+    assertThat(PermissionRule.parseInt("-1")).isEqualTo(-1);
+  }
+
+  @Test
+  public void testEquals() {
+    GroupReference groupReference2 = new GroupReference(new AccountGroup.UUID("uuid2"), "group2");
+    PermissionRule permissionRuleOther = new PermissionRule(groupReference2);
+    assertThat(permissionRule.equals(permissionRuleOther)).isFalse();
+
+    permissionRuleOther.setGroup(groupReference);
+    assertThat(permissionRule.equals(permissionRuleOther)).isTrue();
+
+    permissionRule.setDeny();
+    assertThat(permissionRule.equals(permissionRuleOther)).isFalse();
+
+    permissionRuleOther.setDeny();
+    assertThat(permissionRule.equals(permissionRuleOther)).isTrue();
+
+    permissionRule.setForce(true);
+    assertThat(permissionRule.equals(permissionRuleOther)).isFalse();
+
+    permissionRuleOther.setForce(true);
+    assertThat(permissionRule.equals(permissionRuleOther)).isTrue();
+
+    permissionRule.setMin(-1);
+    assertThat(permissionRule.equals(permissionRuleOther)).isFalse();
+
+    permissionRuleOther.setMin(-1);
+    assertThat(permissionRule.equals(permissionRuleOther)).isTrue();
+
+    permissionRule.setMax(1);
+    assertThat(permissionRule.equals(permissionRuleOther)).isFalse();
+
+    permissionRuleOther.setMax(1);
+    assertThat(permissionRule.equals(permissionRuleOther)).isTrue();
+  }
+
+  private void assertPermissionRule(
+      PermissionRule permissionRule,
+      String expectedGroupName,
+      Action expectedAction,
+      boolean expectedForce,
+      int expectedMin,
+      int expectedMax) {
+    assertThat(permissionRule.getGroup().getName()).isEqualTo(expectedGroupName);
+    assertThat(permissionRule.getAction()).isEqualTo(expectedAction);
+    assertThat(permissionRule.getForce()).isEqualTo(expectedForce);
+    assertThat(permissionRule.getMin()).isEqualTo(expectedMin);
+    assertThat(permissionRule.getMax()).isEqualTo(expectedMax);
+  }
+}
diff --git a/javatests/com/google/gerrit/elasticsearch/BUILD b/javatests/com/google/gerrit/elasticsearch/BUILD
index 1249909..595c887 100644
--- a/javatests/com/google/gerrit/elasticsearch/BUILD
+++ b/javatests/com/google/gerrit/elasticsearch/BUILD
@@ -10,49 +10,84 @@
     visibility = ["//visibility:public"],
     deps = [
         "//java/com/google/gerrit/elasticsearch",
-        "//java/com/google/gerrit/extensions:api",
         "//java/com/google/gerrit/index",
-        "//java/com/google/gerrit/index/project",
-        "//java/com/google/gerrit/reviewdb:server",
         "//java/com/google/gerrit/server",
-        "//lib:gson",
         "//lib:guava",
         "//lib:junit",
         "//lib/guice",
         "//lib/httpcomponents:httpcore",
         "//lib/jgit/org.eclipse.jgit:jgit",
-        "//lib/jgit/org.eclipse.jgit.junit:junit",
         "//lib/testcontainers",
-        "//lib/truth",
     ],
 )
 
-ELASTICSEARCH_TESTS = {i: "ElasticQuery" + i.capitalize() + "sTest.java" for i in [
+ELASTICSEARCH_DEPS = [
+    ":elasticsearch_test_utils",
+    "//java/com/google/gerrit/elasticsearch",
+    "//java/com/google/gerrit/testing:gerrit-test-util",
+    "//lib/guice",
+    "//lib/jgit/org.eclipse.jgit:jgit",
+]
+
+QUERY_TESTS_DEP = "//javatests/com/google/gerrit/server/query/%s:abstract_query_tests"
+
+TYPES = [
     "account",
     "change",
     "group",
     "project",
-]}
+]
+
+SUFFIX = "sTest.java"
+
+ELASTICSEARCH_TESTS = {i: "ElasticQuery" + i.capitalize() + SUFFIX for i in TYPES}
+
+ELASTICSEARCH_TESTS_V5 = {i: "ElasticV5Query" + i.capitalize() + SUFFIX for i in TYPES}
+
+ELASTICSEARCH_TESTS_V6 = {i: "ElasticV6Query" + i.capitalize() + SUFFIX for i in TYPES}
+
+ELASTICSEARCH_TAGS = [
+    "docker",
+    "elastic",
+]
 
 [junit_tests(
     name = "elasticsearch_%ss_test" % name,
     size = "large",
     srcs = [src],
-    tags = [
-        "docker",
-        "elastic",
-    ],
-    deps = [
-        ":elasticsearch_test_utils",
-        "//java/com/google/gerrit/elasticsearch",
-        "//java/com/google/gerrit/server",
-        "//java/com/google/gerrit/server/project/testing:project-test-util",
-        "//java/com/google/gerrit/testing:gerrit-test-util",
-        "//javatests/com/google/gerrit/server/query/%s:abstract_query_tests" % name,
-        "//lib/guice",
-        "//lib/httpcomponents:httpcore",
-        "//lib/jgit/org.eclipse.jgit:jgit",
-        "//lib/jgit/org.eclipse.jgit.junit:junit",
-        "//lib/testcontainers",
-    ],
+    tags = ELASTICSEARCH_TAGS,
+    deps = ELASTICSEARCH_DEPS + [QUERY_TESTS_DEP % name],
 ) for name, src in ELASTICSEARCH_TESTS.items()]
+
+[junit_tests(
+    name = "elasticsearch_%ss_test_V5" % name,
+    size = "large",
+    srcs = [src],
+    tags = ELASTICSEARCH_TAGS,
+    deps = ELASTICSEARCH_DEPS + [QUERY_TESTS_DEP % name],
+) for name, src in ELASTICSEARCH_TESTS_V5.items()]
+
+[junit_tests(
+    name = "elasticsearch_%ss_test_V6" % name,
+    size = "large",
+    srcs = [src],
+    tags = ELASTICSEARCH_TAGS + ["flaky"],
+    deps = ELASTICSEARCH_DEPS + [QUERY_TESTS_DEP % name],
+) for name, src in ELASTICSEARCH_TESTS_V6.items()]
+
+[junit_tests(
+    name = "elasticsearch_tests",
+    size = "small",
+    srcs = glob(
+        ["*Test.java"],
+        exclude = ["Elastic*Query*" + SUFFIX],
+    ),
+    tags = ["elastic"],
+    deps = [
+        "//java/com/google/gerrit/elasticsearch",
+        "//lib:guava",
+        "//lib/guice",
+        "//lib/jgit/org.eclipse.jgit:jgit",
+        "//lib/truth",
+    ],
+)]
diff --git a/javatests/com/google/gerrit/server/extensions/webui/UiActionsTest.java b/javatests/com/google/gerrit/server/extensions/webui/UiActionsTest.java
index 834f658..f63b181 100644
--- a/javatests/com/google/gerrit/server/extensions/webui/UiActionsTest.java
+++ b/javatests/com/google/gerrit/server/extensions/webui/UiActionsTest.java
@@ -18,6 +18,7 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
+import com.google.gerrit.extensions.conditions.BooleanCondition;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.server.CurrentUser;
@@ -43,31 +44,6 @@
     private boolean allowValueQueries = true;
 
     @Override
-    public CurrentUser user() {
-      return new CurrentUser() {
-        @Override
-        public GroupMembership getEffectiveGroups() {
-          throw new UnsupportedOperationException("not implemented");
-        }
-
-        @Override
-        public Object getCacheKey() {
-          return new Object();
-        }
-
-        @Override
-        public boolean isIdentifiedUser() {
-          return true;
-        }
-
-        @Override
-        public Account.Id getAccountId() {
-          return new Account.Id(1);
-        }
-      };
-    }
-
-    @Override
     public String resourcePath() {
       return "/projects/test-project";
     }
@@ -100,6 +76,11 @@
     }
 
     @Override
+    public BooleanCondition testCond(ProjectPermission perm) {
+      return new PermissionBackendCondition.ForProject(this, perm, fakeUser());
+    }
+
+    @Override
     public Map<String, Ref> filter(Map<String, Ref> refs, Repository repo, RefFilterOptions opts)
         throws PermissionBackendException {
       throw new UnsupportedOperationException("not implemented");
@@ -108,6 +89,30 @@
     private void disallowValueQueries() {
       allowValueQueries = false;
     }
+
+    private static CurrentUser fakeUser() {
+      return new CurrentUser() {
+        @Override
+        public GroupMembership getEffectiveGroups() {
+          throw new UnsupportedOperationException("not implemented");
+        }
+
+        @Override
+        public Object getCacheKey() {
+          return new Object();
+        }
+
+        @Override
+        public boolean isIdentifiedUser() {
+          return true;
+        }
+
+        @Override
+        public Account.Id getAccountId() {
+          return new Account.Id(1);
+        }
+      };
+    }
   }
 
   @Test
diff --git a/javatests/com/google/gerrit/server/notedb/ChangeNotesTest.java b/javatests/com/google/gerrit/server/notedb/ChangeNotesTest.java
index bea61ed..3a98127 100644
--- a/javatests/com/google/gerrit/server/notedb/ChangeNotesTest.java
+++ b/javatests/com/google/gerrit/server/notedb/ChangeNotesTest.java
@@ -691,7 +691,7 @@
     try (RevWalk rw = new RevWalk(repo)) {
       RevCommit commit = rw.parseCommit(update.getResult());
       rw.parseBody(commit);
-      String strIdent = otherUser.getName() + " <" + otherUserId + "@" + serverId + ">";
+      String strIdent = "Gerrit User " + otherUserId + " <" + otherUserId + "@" + serverId + ">";
       assertThat(commit.getFullMessage()).contains("Assignee: " + strIdent);
     }
   }
diff --git a/javatests/com/google/gerrit/server/notedb/CommitMessageOutputTest.java b/javatests/com/google/gerrit/server/notedb/CommitMessageOutputTest.java
index f826fec..db7035b 100644
--- a/javatests/com/google/gerrit/server/notedb/CommitMessageOutputTest.java
+++ b/javatests/com/google/gerrit/server/notedb/CommitMessageOutputTest.java
@@ -62,14 +62,14 @@
             + "Commit: "
             + update.getCommit().name()
             + "\n"
-            + "Reviewer: Change Owner <1@gerrit>\n"
-            + "CC: Other Account <2@gerrit>\n"
+            + "Reviewer: Gerrit User 1 <1@gerrit>\n"
+            + "CC: Gerrit User 2 <2@gerrit>\n"
             + "Label: Code-Review=-1\n"
             + "Label: Verified=+1\n",
         commit);
 
     PersonIdent author = commit.getAuthorIdent();
-    assertThat(author.getName()).isEqualTo("Change Owner");
+    assertThat(author.getName()).isEqualTo("Gerrit User 1");
     assertThat(author.getEmailAddress()).isEqualTo("1@gerrit");
     assertThat(author.getWhen()).isEqualTo(new Date(c.getCreatedOn().getTime() + 1000));
     assertThat(author.getTimeZone()).isEqualTo(TimeZone.getTimeZone("GMT-7:00"));
@@ -177,15 +177,15 @@
             + submissionId.toStringForStorage()
             + "\n"
             + "Submitted-with: NOT_READY\n"
-            + "Submitted-with: OK: Verified: Change Owner <1@gerrit>\n"
+            + "Submitted-with: OK: Verified: Gerrit User 1 <1@gerrit>\n"
             + "Submitted-with: NEED: Code-Review\n"
             + "Submitted-with: NOT_READY\n"
-            + "Submitted-with: OK: Verified: Change Owner <1@gerrit>\n"
+            + "Submitted-with: OK: Verified: Gerrit User 1 <1@gerrit>\n"
             + "Submitted-with: NEED: Alternative-Code-Review\n",
         commit);
 
     PersonIdent author = commit.getAuthorIdent();
-    assertThat(author.getName()).isEqualTo("Change Owner");
+    assertThat(author.getName()).isEqualTo("Gerrit User 1");
     assertThat(author.getEmailAddress()).isEqualTo("1@gerrit");
     assertThat(author.getWhen()).isEqualTo(new Date(c.getCreatedOn().getTime() + 2000));
     assertThat(author.getTimeZone()).isEqualTo(TimeZone.getTimeZone("GMT-7:00"));
@@ -210,7 +210,7 @@
     assertBodyEquals("Update patch set 1\n\nComment on the change.\n\nPatch-set: 1\n", commit);
 
     PersonIdent author = commit.getAuthorIdent();
-    assertThat(author.getName()).isEqualTo("GerritAccount #3");
+    assertThat(author.getName()).isEqualTo("Gerrit User 3");
     assertThat(author.getEmailAddress()).isEqualTo("3@gerrit");
   }
 
@@ -245,7 +245,7 @@
     update.commit();
 
     assertBodyEquals(
-        "Update patch set 1\n\nPatch-set: 1\nReviewer: Change Owner <1@gerrit>\n",
+        "Update patch set 1\n\nPatch-set: 1\nReviewer: Gerrit User 1 <1@gerrit>\n",
         update.getResult());
   }
 
@@ -360,7 +360,7 @@
 
     RevCommit commit = parseCommit(update.getResult());
     PersonIdent author = commit.getAuthorIdent();
-    assertThat(author.getName()).isEqualTo("Other Account");
+    assertThat(author.getName()).isEqualTo("Gerrit User 2");
     assertThat(author.getEmailAddress()).isEqualTo("2@gerrit");
 
     assertBodyEquals(
@@ -369,7 +369,7 @@
             + "Message on behalf of other user\n"
             + "\n"
             + "Patch-set: 1\n"
-            + "Real-user: Change Owner <1@gerrit>\n",
+            + "Real-user: Gerrit User 1 <1@gerrit>\n",
         commit);
   }
 
diff --git a/plugins/reviewnotes b/plugins/reviewnotes
index c73171e..920f28b 160000
--- a/plugins/reviewnotes
+++ b/plugins/reviewnotes
@@ -1 +1 @@
-Subproject commit c73171ea9abbeb765d585a92753ce01151355a5c
+Subproject commit 920f28b46021d9c49fac09d869aa4040d13796e7
diff --git a/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row.js b/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row.js
index 396fed8..0682ab2 100644
--- a/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row.js
+++ b/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row.js
@@ -49,12 +49,12 @@
     },
 
     get selectedItem() {
-      if (!this._ironSelector) { return; }
+      if (!this._ironSelector) { return undefined; }
       return this._ironSelector.selectedItem;
     },
 
     get selectedValue() {
-      if (!this._ironSelector) { return; }
+      if (!this._ironSelector) { return undefined; }
       return this._ironSelector.selected;
     },