Determine submittability on the server side

We do not transport all labels to the client side as certain
labels may be hidden from some users. To display the correct
state for submittability for each change, we should rely on the
server stating if it deems a change to be submittable as that is
the same code as in the Merging procedure, so there are no differences.

Change-Id: I44d39a6e777147371936567b868ba517780271a1

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

@@ -137,6 +137,7 @@ public class ChangeJson {
   private final GitRepositoryManager repoManager;
   private final ProjectCache projectCache;
   private final MergeUtil.Factory mergeUtilFactory;
+  private final Submit submit;
   private final IdentifiedUser.GenericFactory userFactory;
   private final ChangeData.Factory changeDataFactory;
   private final FileInfoJson fileInfoJson;
@@ -161,6 +162,7 @@ public class ChangeJson {
       GitRepositoryManager repoManager,
       ProjectCache projectCache,
       MergeUtil.Factory mergeUtilFactory,
+      Submit submit,
       IdentifiedUser.GenericFactory uf,
       ChangeData.Factory cdf,
       FileInfoJson fileInfoJson,
@@ -180,6 +182,7 @@ public class ChangeJson {
     this.repoManager = repoManager;
     this.userFactory = uf;
     this.projectCache = projectCache;
+    this.submit = submit;
     this.mergeUtilFactory = mergeUtilFactory;
     this.fileInfoJson = fileInfoJson;
     this.accountLoaderFactory = ailf;
@@ -383,6 +386,7 @@ public class ChangeJson {
     // the response and avoid making a request to /submit_type from the UI.
     out.mergeable = in.getStatus() == Change.Status.MERGED
         ? null : cd.isMergeable();
+    out.submittable = submit.submittable(cd);
     ChangedLines changedLines = cd.changedLines();
     if (changedLines != null) {
       out.insertions = changedLines.insertions;

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

@@ -248,6 +248,22 @@ public class Submit implements RestModifyView<RevisionResource, SubmitInput>,
     return null;
   }
 
+  /**
+   * Check if there are any problems with the given change. It doesn't take
+   * any problems of related changes into account.
+   * <p>
+   * @param cd the change to check for submittability
+   * @return if the change has any problems for submission
+   */
+  public boolean submittable(ChangeData cd) {
+    try {
+      MergeOp.checkSubmitRule(cd);
+      return true;
+    } catch (ResourceConflictException | OrmException e) {
+      return false;
+    }
+  }
+
   @Override
   public UiAction.Description getDescription(RevisionResource resource) {
     PatchSet.Id current = resource.getChange().currentPatchSetId();

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

@@ -64,9 +64,7 @@ public class SubmittedTogether implements RestReadView<ChangeResource> {
       if (cs.ids().size() > 1) {
         return json.create(EnumSet.of(
             ListChangesOption.CURRENT_REVISION,
-            ListChangesOption.CURRENT_COMMIT,
-            ListChangesOption.DETAILED_LABELS,
-            ListChangesOption.LABELS))
+            ListChangesOption.CURRENT_COMMIT))
           .format(cs.ids());
       } else {
         return Collections.emptyList();