Display empty branch list when project has no repository

If a project exists only to provide permissions inherited by other
projects, it probably has no Git repository, and thus cannot have
any branches.  Instead of crashing with an exception when clicking
on the branches tab in the admin web UI, display a message.

Bug: issue 612
Change-Id: I140ea74e640d732863df2b95eabb6e73787eae11
Signed-off-by: Shawn O. Pearce <sop@google.com>

gerrit-common/src/main/java/com/google/gerrit/common/data/ListBranchesResult.java

@@ -19,35 +19,33 @@ import com.google.gerrit.reviewdb.Branch;
 import java.util.List;
 
 /**
- * It holds list of branches and boolean to indicate
- * if it is allowed to add new branches.
+ * It holds list of branches and boolean to indicate if it is allowed to add new
+ * branches.
  */
 public final class ListBranchesResult {
+  protected boolean noRepository;
   protected boolean canAdd;
-
   protected List<Branch> branches;
 
   protected ListBranchesResult() {
   }
 
-  public ListBranchesResult(final List<Branch> branches, boolean canAdd) {
+  public ListBranchesResult(List<Branch> branches, boolean canAdd,
+      boolean noRepository) {
     this.branches = branches;
     this.canAdd = canAdd;
+    this.noRepository = noRepository;
+  }
+
+  public boolean getNoRepository() {
+    return noRepository;
   }
 
   public boolean getCanAdd() {
     return canAdd;
   }
 
-  public void setCanAdd(boolean canAdd) {
-    this.canAdd = canAdd;
-  }
-
   public List<Branch> getBranches() {
     return branches;
   }
-
-  public void setBranches(List<Branch> branches) {
-    this.branches = branches;
-  }
 }

gerrit-gwtui/src/main/java/com/google/gerrit/client/admin/AdminConstants.java

@@ -88,4 +88,5 @@ public interface AdminConstants extends Constants {
 
   String noGroupSelected();
   String errorNoMatchingGroups();
+  String errorNoGitRepository();
 }

gerrit-gwtui/src/main/java/com/google/gerrit/client/admin/AdminConstants.properties

@@ -69,3 +69,4 @@ projectAdminTabAccess = Access
 
 noGroupSelected = (No group selected)
 errorNoMatchingGroups = No Matching Groups
+errorNoGitRepository = No Git Repository

gerrit-gwtui/src/main/java/com/google/gerrit/client/admin/ProjectBranchesScreen.java

@@ -40,6 +40,7 @@ import com.google.gwt.user.client.ui.CheckBox;
 import com.google.gwt.user.client.ui.FlowPanel;
 import com.google.gwt.user.client.ui.Grid;
 import com.google.gwt.user.client.ui.HTML;
+import com.google.gwt.user.client.ui.Label;
 import com.google.gwt.user.client.ui.FlexTable.FlexCellFormatter;
 import com.google.gwtjsonrpc.client.RemoteJsonException;
 
@@ -64,10 +65,22 @@ public class ProjectBranchesScreen extends ProjectScreen {
     super.onLoad();
     Util.PROJECT_SVC.listBranches(getProjectKey(),
         new ScreenLoadCallback<ListBranchesResult>(this) {
+          @Override
           public void preDisplay(final ListBranchesResult result) {
-            enableForm(true);
-            display(result.getBranches());
-            addPanel.setVisible(result.getCanAdd());
+            if (result.getNoRepository()) {
+              branches.setVisible(false);
+              addPanel.setVisible(false);
+              delBranch.setVisible(false);
+
+              Label no = new Label(Util.C.errorNoGitRepository());
+              no.setStyleName(Gerrit.RESOURCES.css().smallHeading());
+              add(no);
+
+            } else {
+              enableForm(true);
+              display(result.getBranches());
+              addPanel.setVisible(result.getCanAdd());
+            }
           }
         });
   }

gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/project/ListBranches.java

@@ -60,15 +60,20 @@ class ListBranches extends Handler<ListBranchesResult> {
   }
 
   @Override
-  public ListBranchesResult call() throws NoSuchProjectException,
-      RepositoryNotFoundException {
+  public ListBranchesResult call() throws NoSuchProjectException {
     final ProjectControl pctl = projectControlFactory.validateFor( //
         projectName, //
         ProjectControl.OWNER | ProjectControl.VISIBLE);
 
     final List<Branch> branches = new ArrayList<Branch>();
     Branch headBranch = null;
-    final Repository db = repoManager.openRepository(projectName.get());
+
+    final Repository db;
+    try {
+      db = repoManager.openRepository(projectName.get());
+    } catch (RepositoryNotFoundException noGitRepository) {
+      return new ListBranchesResult(branches, false, true);
+    }
     try {
       final Map<String, Ref> all = db.getAllRefs();
 
@@ -139,7 +144,7 @@ class ListBranches extends Handler<ListBranchesResult> {
     if (headBranch != null) {
       branches.add(0, headBranch);
     }
-    return new ListBranchesResult(branches, pctl.canAddRefs());
+    return new ListBranchesResult(branches, pctl.canAddRefs(), false);
   }
 
   private Branch createBranch(final String name) {