Support different project level merge policies

Replace the hidden "gerrit.fastforwardonly" config file option with
a project level property stored in the database containing one of
three different values:

 * FAST_FORWARD_ONLY:  Never create a merge commit
 * MERGE_IF_NECESSARY: Standard/default behavior
 * MERGE_ALWAYS:       Always create a merge commit

Signed-off-by: Shawn O. Pearce <sop@google.com>

12 files changed, 306 insertions, 12 deletions

diff --git a/Documentation/project-setup.txt b/Documentation/project-setup.txt
index 3e7f5fa4c8..c71507e152 100644
--- a/Documentation/project-setup.txt
+++ b/Documentation/project-setup.txt
@@ -43,11 +43,13 @@ for a project named `project`.
   INSERT INTO projects
   (project_id
    ,use_contributor_agreements
+   ,submit_type
    ,owner_group_id
    ,name)
   VALUES
   (nextval('project_id')
   ,'Y'
+  ,'M'
   ,(SELECT admin_group_id FROM system_config)
   ,'new/project');
 
@@ -61,6 +63,40 @@ for a project named `project`.
   ,'new/project');
 ====
 
+Change Submit Action
+--------------------
+
+The method Gerrit uses to submit a change to a project can be
+modified by any project owner through the project console, `Admin` >
+`Projects`.  The following methods are supported:
+
+* Fast Forward Only
++
+This method produces a strictly linear history.  All merges must
+be handled on the client, prior to uploading to Gerrit for review.
++
+To submit a change, the change must be a strict superset of the
+destination branch.  That is, the change must already contain the
+tip of the destination branch at submit time.
+
+* Merge If Necessary
++
+This is the default for a new project (and why `\'M'` is suggested
+above in the insert statement).
++
+If the change being submitted is a strict superset of the destination
+branch, then the branch is fast-forwarded to the change.  If not,
+then a merge commit is automatically created.  This is identical
+to the classical `git merge` behavior, or `git merge \--ff`.
+
+* Always Merge
++
+Always produce a merge commit, even if the change is a strict
+superset of the destination branch.  This is identical to the
+behavior of `git merge \--no-ff`, and may be useful if the
+project needs to follow submits with `git log \--first-parent`.
+
+
 Registering Additional Branches
 -------------------------------
 
diff --git a/src/main/java/com/google/gerrit/client/admin/AdminConstants.java b/src/main/java/com/google/gerrit/client/admin/AdminConstants.java
index d3b93df9f5..1feb05353e 100644
--- a/src/main/java/com/google/gerrit/client/admin/AdminConstants.java
+++ b/src/main/java/com/google/gerrit/client/admin/AdminConstants.java
@@ -32,10 +32,15 @@ public interface AdminConstants extends Constants {
 
   String headingOwner();
   String headingDescription();
+  String headingSubmitType();
   String headingMembers();
   String headingCreateGroup();
   String headingAccessRights();
 
+  String projectSubmitType_FAST_FORWARD_ONLY();
+  String projectSubmitType_MERGE_ALWAYS();
+  String projectSubmitType_MERGE_IF_NECESSARY();
+
   String columnMember();
   String columnEmailAddress();
   String columnGroupName();
diff --git a/src/main/java/com/google/gerrit/client/admin/AdminConstants.properties b/src/main/java/com/google/gerrit/client/admin/AdminConstants.properties
index 94bff9eb3c..16c57d7a2d 100644
--- a/src/main/java/com/google/gerrit/client/admin/AdminConstants.properties
+++ b/src/main/java/com/google/gerrit/client/admin/AdminConstants.properties
@@ -13,10 +13,15 @@ buttonAddProjectRight = Add Access Right
 
 headingOwner = Owners
 headingDescription = Description
+headingSubmitType = Change Submit Action
 headingMembers = Members
 headingCreateGroup = Create New Group
 headingAccessRights = Access Rights
 
+projectSubmitType_FAST_FORWARD_ONLY = Fast Forward Only
+projectSubmitType_MERGE_IF_NECESSARY = Merge If Necessary
+projectSubmitType_MERGE_ALWAYS = Always Merge
+
 columnMember = Member
 columnEmailAddress = Email Address
 columnGroupName = Group Name
diff --git a/src/main/java/com/google/gerrit/client/admin/ProjectAdminService.java b/src/main/java/com/google/gerrit/client/admin/ProjectAdminService.java
index d92e066d22..f9a4898558 100644
--- a/src/main/java/com/google/gerrit/client/admin/ProjectAdminService.java
+++ b/src/main/java/com/google/gerrit/client/admin/ProjectAdminService.java
@@ -42,6 +42,10 @@ public interface ProjectAdminService extends RemoteJsonService {
       AsyncCallback<VoidResult> callback);
 
   @SignInRequired
+  void changeProjectSubmitType(Project.Id projectId,
+      Project.SubmitType newSubmitType, AsyncCallback<VoidResult> callback);
+
+  @SignInRequired
   void deleteRight(Set<ProjectRight.Key> ids, AsyncCallback<VoidResult> callback);
 
   @SignInRequired
diff --git a/src/main/java/com/google/gerrit/client/admin/ProjectInfoPanel.java b/src/main/java/com/google/gerrit/client/admin/ProjectInfoPanel.java
index e0c9f25283..35350d5028 100644
--- a/src/main/java/com/google/gerrit/client/admin/ProjectInfoPanel.java
+++ b/src/main/java/com/google/gerrit/client/admin/ProjectInfoPanel.java
@@ -22,9 +22,11 @@ import com.google.gerrit.client.ui.AccountGroupSuggestOracle;
 import com.google.gerrit.client.ui.SmallHeading;
 import com.google.gerrit.client.ui.TextSaveButtonListener;
 import com.google.gwt.user.client.ui.Button;
+import com.google.gwt.user.client.ui.ChangeListener;
 import com.google.gwt.user.client.ui.ClickListener;
 import com.google.gwt.user.client.ui.Composite;
 import com.google.gwt.user.client.ui.FlowPanel;
+import com.google.gwt.user.client.ui.ListBox;
 import com.google.gwt.user.client.ui.Panel;
 import com.google.gwt.user.client.ui.SuggestBox;
 import com.google.gwt.user.client.ui.TextArea;
@@ -41,6 +43,10 @@ public class ProjectInfoPanel extends Composite {
   private SuggestBox ownerTxt;
   private Button saveOwner;
 
+  private Panel submitTypePanel;
+  private ListBox submitType;
+  private Project.SubmitType currentSubmitType;
+
   private TextArea descTxt;
   private Button saveDesc;
 
@@ -48,6 +54,7 @@ public class ProjectInfoPanel extends Composite {
     final FlowPanel body = new FlowPanel();
     initOwner(body);
     initDescription(body);
+    initSubmitType(body);
     initWidget(body);
 
     projectId = toShow;
@@ -72,6 +79,7 @@ public class ProjectInfoPanel extends Composite {
   }
 
   private void enableForm(final boolean on) {
+    submitType.setEnabled(on);
     ownerTxtBox.setEnabled(on);
     descTxt.setEnabled(on);
   }
@@ -132,6 +140,56 @@ public class ProjectInfoPanel extends Composite {
     new TextSaveButtonListener(descTxt, saveDesc);
   }
 
+  private void initSubmitType(final Panel body) {
+    submitTypePanel = new VerticalPanel();
+    submitTypePanel.add(new SmallHeading(Util.C.headingSubmitType()));
+
+    submitType = new ListBox();
+    for (final Project.SubmitType type : Project.SubmitType.values()) {
+      submitType.addItem(Util.toLongString(type), type.name());
+    }
+    submitType.addChangeListener(new ChangeListener() {
+      public void onChange(Widget sender) {
+        final int i = submitType.getSelectedIndex();
+        if (i < 0) {
+          return;
+        }
+        final Project.SubmitType newSubmitType =
+            Project.SubmitType.valueOf(submitType.getValue(i));
+        submitType.setEnabled(false);
+        Util.PROJECT_SVC.changeProjectSubmitType(projectId, newSubmitType,
+            new GerritCallback<VoidResult>() {
+              public void onSuccess(final VoidResult result) {
+                currentSubmitType = newSubmitType;
+                submitType.setEnabled(true);
+              }
+
+              @Override
+              public void onFailure(final Throwable caught) {
+                submitType.setEnabled(false);
+                setSubmitType(currentSubmitType);
+                super.onFailure(caught);
+              }
+            });
+      }
+    });
+    submitTypePanel.add(submitType);
+    body.add(submitTypePanel);
+  }
+
+  private void setSubmitType(final Project.SubmitType newSubmitType) {
+    currentSubmitType = newSubmitType;
+    if (submitType != null) {
+      for (int i = 0; i < submitType.getItemCount(); i++) {
+        if (newSubmitType.name().equals(submitType.getValue(i))) {
+          submitType.setSelectedIndex(i);
+          return;
+        }
+      }
+      submitType.setSelectedIndex(-1);
+    }
+  }
+
   void display(final ProjectDetail result) {
     final Project project = result.project;
     final AccountGroup owner = result.groups.get(project.getOwnerGroupId());
@@ -143,10 +201,13 @@ public class ProjectInfoPanel extends Composite {
 
     if (ProjectRight.WILD_PROJECT.equals(project.getId())) {
       ownerPanel.setVisible(false);
+      submitTypePanel.setVisible(false);
     } else {
       ownerPanel.setVisible(true);
+      submitTypePanel.setVisible(true);
     }
 
     descTxt.setText(project.getDescription());
+    setSubmitType(project.getSubmitType());
   }
 }
diff --git a/src/main/java/com/google/gerrit/client/admin/Util.java b/src/main/java/com/google/gerrit/client/admin/Util.java
index 9b87cf19df..40603d3f74 100644
--- a/src/main/java/com/google/gerrit/client/admin/Util.java
+++ b/src/main/java/com/google/gerrit/client/admin/Util.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.client.admin;
 
+import com.google.gerrit.client.reviewdb.Project;
 import com.google.gwt.core.client.GWT;
 import com.google.gwtjsonrpc.client.JsonUtil;
 
@@ -30,4 +31,20 @@ public class Util {
     PROJECT_SVC = GWT.create(ProjectAdminService.class);
     JsonUtil.bind(PROJECT_SVC, "rpc/ProjectAdminService");
   }
+
+  public static String toLongString(final Project.SubmitType type) {
+    if (type == null) {
+      return "";
+    }
+    switch (type) {
+      case FAST_FORWARD_ONLY:
+        return C.projectSubmitType_FAST_FORWARD_ONLY();
+      case MERGE_IF_NECESSARY:
+        return C.projectSubmitType_MERGE_IF_NECESSARY();
+      case MERGE_ALWAYS:
+        return C.projectSubmitType_MERGE_ALWAYS();
+      default:
+        return type.name();
+    }
+  }
 }
diff --git a/src/main/java/com/google/gerrit/client/reviewdb/Project.java b/src/main/java/com/google/gerrit/client/reviewdb/Project.java
index 4a9f0f2ea7..df97cfe0ed 100644
--- a/src/main/java/com/google/gerrit/client/reviewdb/Project.java
+++ b/src/main/java/com/google/gerrit/client/reviewdb/Project.java
@@ -81,6 +81,33 @@ public final class Project {
     }
   }
 
+  public static enum SubmitType {
+    FAST_FORWARD_ONLY('F'),
+
+    MERGE_IF_NECESSARY('M'),
+
+    MERGE_ALWAYS('A');
+
+    private final char code;
+
+    private SubmitType(final char c) {
+      code = c;
+    }
+
+    public char getCode() {
+      return code;
+    }
+
+    public static SubmitType forCode(final char c) {
+      for (final SubmitType s : SubmitType.values()) {
+        if (s.code == c) {
+          return s;
+        }
+      }
+      return null;
+    }
+  }
+
   @Column
   protected NameKey name;
 
@@ -96,6 +123,9 @@ public final class Project {
   @Column
   protected boolean useContributorAgreements;
 
+  @Column
+  protected char submitType;
+
   protected Project() {
   }
 
@@ -103,6 +133,7 @@ public final class Project {
     name = newName;
     projectId = newId;
     useContributorAgreements = true;
+    setSubmitType(SubmitType.MERGE_IF_NECESSARY);
   }
 
   public Project.Id getId() {
@@ -140,4 +171,12 @@ public final class Project {
   public void setUseContributorAgreements(final boolean u) {
     useContributorAgreements = u;
   }
+
+  public SubmitType getSubmitType() {
+    return SubmitType.forCode(submitType);
+  }
+
+  public void setSubmitType(final SubmitType type) {
+    submitType = type.getCode();
+  }
 }
diff --git a/src/main/java/com/google/gerrit/client/reviewdb/ReviewDb.java b/src/main/java/com/google/gerrit/client/reviewdb/ReviewDb.java
index 1f2d9599c2..a9f853a2f0 100644
--- a/src/main/java/com/google/gerrit/client/reviewdb/ReviewDb.java
+++ b/src/main/java/com/google/gerrit/client/reviewdb/ReviewDb.java
@@ -21,7 +21,7 @@ import com.google.gwtorm.client.Sequence;
 
 /** The review service database schema. */
 public interface ReviewDb extends Schema {
-  public static final int VERSION = 8;
+  public static final int VERSION = 9;
 
   @Relation
   SchemaVersionAccess schemaVersion();
diff --git a/src/main/java/com/google/gerrit/git/MergeOp.java b/src/main/java/com/google/gerrit/git/MergeOp.java
index ac5da117e8..e77e817d3b 100644
--- a/src/main/java/com/google/gerrit/git/MergeOp.java
+++ b/src/main/java/com/google/gerrit/git/MergeOp.java
@@ -15,12 +15,14 @@
 package com.google.gerrit.git;
 
 import com.google.gerrit.client.data.ApprovalType;
+import com.google.gerrit.client.data.ProjectCache;
 import com.google.gerrit.client.reviewdb.ApprovalCategory;
 import com.google.gerrit.client.reviewdb.Branch;
 import com.google.gerrit.client.reviewdb.Change;
 import com.google.gerrit.client.reviewdb.ChangeApproval;
 import com.google.gerrit.client.reviewdb.ChangeMessage;
 import com.google.gerrit.client.reviewdb.PatchSet;
+import com.google.gerrit.client.reviewdb.Project;
 import com.google.gerrit.client.reviewdb.ReviewDb;
 import com.google.gerrit.client.rpc.Common;
 import com.google.gerrit.client.workflow.FunctionState;
@@ -84,6 +86,7 @@ public class MergeOp {
   private final GerritServer server;
   private final PersonIdent myIdent;
   private final Branch.NameKey destBranch;
+  private Project destProject;
   private final List<CodeReviewCommit> toMerge;
   private List<Change> submitted;
   private final Map<Change.Id, CommitMergeStatus> status;
@@ -103,6 +106,13 @@ public class MergeOp {
   }
 
   public void merge() throws MergeException {
+    final ProjectCache.Entry pe =
+        Common.getProjectCache().get(destBranch.getParentKey());
+    if (pe == null) {
+      throw new MergeException("No such project: " + destBranch.getParentKey());
+    }
+    destProject = pe.getProject();
+
     try {
       schema = Common.getSchemaFactory().open();
     } catch (OrmException e) {
@@ -274,23 +284,24 @@ public class MergeOp {
 
     // Take the first fast-forward available, if any is available in the set.
     //
-    for (final Iterator<CodeReviewCommit> i = toMerge.iterator(); i.hasNext();) {
-      try {
-        final CodeReviewCommit n = i.next();
-        if (mergeTip == null || rw.isMergedInto(mergeTip, n)) {
-          mergeTip = n;
-          i.remove();
-          break;
+    if (destProject.getSubmitType() != Project.SubmitType.MERGE_ALWAYS) {
+      for (final Iterator<CodeReviewCommit> i = toMerge.iterator(); i.hasNext();) {
+        try {
+          final CodeReviewCommit n = i.next();
+          if (mergeTip == null || rw.isMergedInto(mergeTip, n)) {
+            mergeTip = n;
+            i.remove();
+            break;
+          }
+        } catch (IOException e) {
+          throw new MergeException("Cannot fast-forward test during merge", e);
         }
-      } catch (IOException e) {
-        throw new MergeException("Cannot fast-forward test during merge", e);
       }
     }
 
     // If this project only permits fast-forwards, abort everything else.
     //
-    if ("true".equals(db.getConfig().getString("gerrit", null,
-        "fastforwardonly"))) {
+    if (destProject.getSubmitType() == Project.SubmitType.FAST_FORWARD_ONLY) {
       while (!toMerge.isEmpty()) {
         final CodeReviewCommit n = toMerge.remove(0);
         n.statusCode = CommitMergeStatus.PATH_CONFLICT;
diff --git a/src/main/java/com/google/gerrit/pgm/ImportProjectSubmitTypes.java b/src/main/java/com/google/gerrit/pgm/ImportProjectSubmitTypes.java
new file mode 100644
index 0000000000..24371253ca
--- /dev/null
+++ b/src/main/java/com/google/gerrit/pgm/ImportProjectSubmitTypes.java
@@ -0,0 +1,89 @@
+// Copyright (C) 2009 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.pgm;
+
+import com.google.gerrit.client.reviewdb.Project;
+import com.google.gerrit.client.reviewdb.ReviewDb;
+import com.google.gerrit.client.rpc.Common;
+import com.google.gerrit.git.InvalidRepositoryException;
+import com.google.gerrit.git.WorkQueue;
+import com.google.gerrit.server.GerritServer;
+import com.google.gwtjsonrpc.server.XsrfException;
+import com.google.gwtorm.client.OrmException;
+
+import org.spearce.jgit.lib.ProgressMonitor;
+import org.spearce.jgit.lib.Repository;
+import org.spearce.jgit.lib.TextProgressMonitor;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+
+/** Update project's submit_type field from their git config files. */
+public class ImportProjectSubmitTypes {
+  private static final String GERRIT = "gerrit";
+  private static final String FFO = "fastforwardonly";
+
+  public static void main(final String[] argv) throws OrmException,
+      XsrfException {
+    try {
+      mainImpl(argv);
+    } finally {
+      WorkQueue.terminate();
+    }
+  }
+
+  private static void mainImpl(final String[] argv) throws OrmException,
+      XsrfException {
+    final ProgressMonitor pm = new TextProgressMonitor();
+    final GerritServer gs = GerritServer.getInstance();
+    final ReviewDb db = Common.getSchemaFactory().open();
+    try {
+      final List<Project> all = db.projects().all().toList();
+      pm.start(1);
+      pm.beginTask("Update projects", all.size());
+      for (final Project p : all) {
+        if (p.getSubmitType() != null
+            && p.getSubmitType() != Project.SubmitType.MERGE_IF_NECESSARY) {
+          pm.update(1);
+          continue;
+        }
+
+        final Repository r;
+        try {
+          r = gs.getRepositoryCache().get(p.getName());
+        } catch (InvalidRepositoryException e) {
+          pm.update(1);
+          continue;
+        }
+
+        if ("true".equals(r.getConfig().getString(GERRIT, null, FFO))) {
+          p.setSubmitType(Project.SubmitType.FAST_FORWARD_ONLY);
+          db.projects().update(Collections.singleton(p));
+          r.getConfig().unsetString(GERRIT, null, FFO);
+          try {
+            r.getConfig().save();
+          } catch (IOException e) {
+            // Ignore a save error
+          }
+        }
+        pm.update(1);
+      }
+      pm.endTask();
+    } finally {
+      db.close();
+    }
+  }
+}
diff --git a/src/main/java/com/google/gerrit/server/ProjectAdminServiceImpl.java b/src/main/java/com/google/gerrit/server/ProjectAdminServiceImpl.java
index 1cfc31a6dc..62e91c98d5 100644
--- a/src/main/java/com/google/gerrit/server/ProjectAdminServiceImpl.java
+++ b/src/main/java/com/google/gerrit/server/ProjectAdminServiceImpl.java
@@ -180,6 +180,24 @@ public class ProjectAdminServiceImpl extends BaseServiceImplementation
     });
   }
 
+  public void changeProjectSubmitType(final Project.Id projectId,
+      final Project.SubmitType newSubmitType,
+      final AsyncCallback<VoidResult> callback) {
+    run(callback, new Action<VoidResult>() {
+      public VoidResult run(final ReviewDb db) throws OrmException, Failure {
+        assertAmProjectOwner(db, projectId);
+        final Project project = db.projects().get(projectId);
+        if (project == null) {
+          throw new Failure(new NoSuchEntityException());
+        }
+        project.setSubmitType(newSubmitType);
+        db.projects().update(Collections.singleton(project));
+        Common.getProjectCache().invalidate(project);
+        return VoidResult.INSTANCE;
+      }
+    });
+  }
+
   public void deleteRight(final Set<ProjectRight.Key> keys,
       final AsyncCallback<VoidResult> callback) {
     run(callback, new Action<VoidResult>() {
diff --git a/src/main/webapp/WEB-INF/sql/upgrade008_009.sql b/src/main/webapp/WEB-INF/sql/upgrade008_009.sql
new file mode 100644
index 0000000000..562cf0a5f6
--- /dev/null
+++ b/src/main/webapp/WEB-INF/sql/upgrade008_009.sql
@@ -0,0 +1,9 @@
+-- Upgrade: schema_version 8 to 9
+--
+
+ALTER TABLE projects ADD submit_type CHAR(1);
+UPDATE projects SET submit_type = 'M'; -- MERGE_IF_NECESSARY
+ALTER TABLE projects ALTER COLUMN submit_type SET DEFAULT ' ';
+ALTER TABLE projects ALTER COLUMN submit_type SET NOT NULL;
+
+UPDATE schema_version SET version_nbr = 9;