Provide a way to lock patch sets

Add a new function type that provides a way to prevent new patch sets
from being added to a change. Defining a label with this function and
applying a +1 vote with that label onto a change will stop: 1) new
patch upload, 2) rebase, and 3) abandon.

Like NoBlock/NoOp, its value will never affect submittability.

Change-Id: Ib0d81d85e797f522d80da8c474a711ec5021f4b6

Documentation/config-labels.txt

@@ -217,6 +217,19 @@ the lowest possible negative value will not block the change.
 The label is purely informational and values are not considered when
 determining whether a change is submittable.
 
+* `PatchSetLock`
++
+The `PatchSetLock` function provides a locking mechanism for patch
+sets.  This function's values are not considered when determining
+whether a change is submittable. When set, no new patchsets can be
+created and rebase and abandon are blocked.
++
+This function is designed to allow overlapping locks, so several lock
+accounts could lock the same change.
++
+Allowed range of values are 0 (Patch Set Unlocked) to 1 (Patch Set
+Locked).
+
 
 [[label_copyMinScore]]
 === `label.Label-Name.copyMinScore`

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/git/AbstractPushForReview.java

@@ -17,6 +17,7 @@ package com.google.gerrit.acceptance.git;
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.TruthJUnit.assume;
 import static com.google.gerrit.acceptance.GitUtil.pushHead;
+import static com.google.gerrit.server.group.SystemGroupBackend.ANONYMOUS_USERS;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.concurrent.TimeUnit.SECONDS;
 
@@ -26,11 +27,19 @@ import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.GitUtil;
 import com.google.gerrit.acceptance.PushOneCommit;
 import com.google.gerrit.acceptance.TestAccount;
+import com.google.gerrit.common.data.LabelType;
+import com.google.gerrit.common.data.Permission;
+import com.google.gerrit.extensions.api.changes.ReviewInput;
 import com.google.gerrit.extensions.client.InheritableBoolean;
 import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.EditInfo;
 import com.google.gerrit.extensions.common.LabelInfo;
+import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.server.git.MetaDataUpdate;
+import com.google.gerrit.server.git.ProjectConfig;
+import com.google.gerrit.server.group.SystemGroupBackend;
+import com.google.gerrit.server.project.Util;
 
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.joda.time.DateTime;
@@ -51,6 +60,7 @@ public abstract class AbstractPushForReview extends AbstractDaemonTest {
   }
 
   private String sshUrl;
+  private LabelType patchSetLock;
 
   @BeforeClass
   public static void setTimeForTesting() {
@@ -73,6 +83,24 @@ public abstract class AbstractPushForReview extends AbstractDaemonTest {
   @Before
   public void setUp() throws Exception {
     sshUrl = sshSession.getUrl();
+    ProjectConfig cfg = projectCache.checkedGet(project).getConfig();
+    patchSetLock = Util.patchSetLock();
+    cfg.getLabelSections().put(patchSetLock.getName(), patchSetLock);
+    AccountGroup.UUID anonymousUsers =
+        SystemGroupBackend.getGroup(ANONYMOUS_USERS).getUUID();
+    Util.allow(cfg, Permission.forLabel(patchSetLock.getName()), 0, 1, anonymousUsers,
+        "refs/heads/*");
+    saveProjectConfig(cfg);
+    grant(Permission.LABEL + "Patch-Set-Lock", project, "refs/heads/*");
+  }
+
+  private void saveProjectConfig(ProjectConfig cfg) throws Exception {
+    MetaDataUpdate md = metaDataUpdateFactory.create(project);
+    try {
+      cfg.commit(md);
+    } finally {
+      md.close();
+    }
   }
 
   protected void selectProtocol(Protocol p) throws Exception {
@@ -275,6 +303,18 @@ public abstract class AbstractPushForReview extends AbstractDaemonTest {
     r.assertOkStatus();
   }
 
+  @Test
+  public void testPushNewPatchsetToPatchSetLockedChange() throws Exception {
+    PushOneCommit.Result r = pushTo("refs/for/master");
+    r.assertOkStatus();
+    PushOneCommit push = pushFactory.create(db, admin.getIdent(), testRepo,
+        PushOneCommit.SUBJECT, "b.txt", "anotherContent", r.getChangeId());
+    revision(r).review(new ReviewInput().label("Patch-Set-Lock", 1));
+    r = push.to("refs/for/master");
+    r.assertErrorStatus("cannot replace " + r.getChange().change().getChangeId()
+        + ". Change is patch set locked.");
+  }
+
   @Test
   public void testPushForMasterWithApprovals_MissingLabel() throws Exception {
       PushOneCommit.Result r = pushTo("refs/for/master/%l=Verify");

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

@@ -82,7 +82,7 @@ public class Abandon implements RestModifyView<ChangeResource, AbandonInput>,
       throws RestApiException, UpdateException, OrmException {
     ChangeControl control = req.getControl();
     IdentifiedUser caller = control.getUser().asIdentifiedUser();
-    if (!control.canAbandon()) {
+    if (!control.canAbandon(dbProvider.get())) {
       throw new AuthException("abandon not permitted");
     }
     Change change = abandon(control, input.message, caller.getAccount());
@@ -174,12 +174,18 @@ public class Abandon implements RestModifyView<ChangeResource, AbandonInput>,
 
   @Override
   public UiAction.Description getDescription(ChangeResource resource) {
+    boolean canAbandon = false;
+    try {
+      canAbandon = resource.getControl().canAbandon(dbProvider.get());
+    } catch (OrmException e) {
+      log.error("Cannot check canAbandon status. Assuming false.", e);
+    }
     return new UiAction.Description()
       .setLabel("Abandon")
       .setTitle("Abandon the change")
       .setVisible(resource.getChange().getStatus().isOpen()
           && resource.getChange().getStatus() != Change.Status.DRAFT
-          && resource.getControl().canAbandon());
+          && canAbandon);
   }
 
   private static String status(Change change) {

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

@@ -90,7 +90,7 @@ public class Rebase implements RestModifyView<RevisionResource, RebaseInput>,
         ObjectInserter oi = repo.newObjectInserter();
         BatchUpdate bu = updateFactory.create(dbProvider.get(),
           change.getProject(), rsrc.getUser(), TimeUtil.nowTs())) {
-      if (!control.canRebase()) {
+      if (!control.canRebase(dbProvider.get())) {
         throw new AuthException("rebase not permitted");
       } else if (!change.getStatus().isOpen()) {
         throw new ResourceConflictException("change is "
@@ -209,9 +209,15 @@ public class Rebase implements RestModifyView<RevisionResource, RebaseInput>,
   public UiAction.Description getDescription(RevisionResource resource) {
     PatchSet patchSet = resource.getPatchSet();
     Branch.NameKey dest = resource.getChange().getDest();
+    boolean canRebase = false;
+    try {
+      canRebase = resource.getControl().canRebase(dbProvider.get());
+    } catch (OrmException e) {
+      log.error("Cannot check canRebase status. Assuming false.", e);
+    }
     boolean visible = resource.getChange().getStatus().isOpen()
           && resource.isCurrent()
-          && resource.getControl().canRebase();
+          && canRebase;
     boolean enabled = true;
 
     if (visible) {

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

@@ -80,7 +80,7 @@ public class Restore implements RestModifyView<ChangeResource, RestoreInput>,
   public ChangeInfo apply(ChangeResource req, RestoreInput input)
       throws RestApiException, UpdateException, OrmException {
     ChangeControl ctl = req.getControl();
-    if (!ctl.canRestore()) {
+    if (!ctl.canRestore(dbProvider.get())) {
       throw new AuthException("restore not permitted");
     }
 
@@ -160,11 +160,17 @@ public class Restore implements RestModifyView<ChangeResource, RestoreInput>,
 
   @Override
   public UiAction.Description getDescription(ChangeResource resource) {
+    boolean canRestore = false;
+    try {
+      canRestore = resource.getControl().canRestore(dbProvider.get());
+    } catch (OrmException e) {
+      log.error("Cannot check canRestore status. Assuming false.", e);
+    }
     return new UiAction.Description()
       .setLabel("Restore")
       .setTitle("Restore the change")
       .setVisible(resource.getChange().getStatus() == Status.ABANDONED
-          && resource.getControl().canRestore());
+          && canRestore);
   }
 
   private static String status(Change change) {

gerrit-server/src/main/java/com/google/gerrit/server/git/ProjectConfig.java

@@ -141,7 +141,7 @@ public class ProjectConfig extends VersionedMetaData implements ValidationError.
   private static final String KEY_CAN_OVERRIDE = "canOverride";
   private static final String KEY_Branch = "branch";
   private static final Set<String> LABEL_FUNCTIONS = ImmutableSet.of(
-      "MaxWithBlock", "AnyWithBlock", "MaxNoBlock", "NoBlock", "NoOp");
+      "MaxWithBlock", "AnyWithBlock", "MaxNoBlock", "NoBlock", "NoOp", "PatchSetLock");
 
   private static final String PLUGIN = "plugin";
 

gerrit-server/src/main/java/com/google/gerrit/server/git/ReceiveCommits.java

@@ -1966,7 +1966,7 @@ public class ReceiveCommits {
       }
     }
 
-    boolean validate(boolean autoClose) throws IOException {
+    boolean validate(boolean autoClose) throws IOException, OrmException {
       if (!autoClose && inputCommand.getResult() != NOT_ATTEMPTED) {
         return false;
       } else if (change == null) {
@@ -1989,8 +1989,12 @@ public class ReceiveCommits {
       }
 
       changeCtl = projectControl.controlFor(change);
-      if (!changeCtl.canAddPatchSet()) {
+      if (!changeCtl.canAddPatchSet(db)) {
-        reject(inputCommand, "cannot replace " + ontoChange);
+        String locked = ".";
+        if (changeCtl.isPatchSetLocked(db)) {
+          locked = ". Change is patch set locked.";
+        }
+        reject(inputCommand, "cannot replace " + ontoChange + locked);
         return false;
       } else if (change.getStatus().isClosed()) {
         reject(inputCommand, "change " + ontoChange + " closed");

gerrit-server/src/main/java/com/google/gerrit/server/project/ChangeControl.java

@@ -28,6 +28,7 @@ import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.client.PatchSetApproval;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.ApprovalsUtil;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.query.change.ChangeData;
@@ -103,23 +104,27 @@ public class ChangeControl {
   private final ChangeData.Factory changeDataFactory;
   private final RefControl refControl;
   private final ChangeNotes notes;
+  private final ApprovalsUtil approvalsUtil;
 
   @AssistedInject
   ChangeControl(
       ChangeData.Factory changeDataFactory,
       ChangeNotes.Factory notesFactory,
+      ApprovalsUtil approvalsUtil,
       @Assisted RefControl refControl,
       @Assisted Change change) {
-    this(changeDataFactory, refControl,
+    this(changeDataFactory, approvalsUtil, refControl,
         notesFactory.create(change));
   }
 
   @AssistedInject
   ChangeControl(
       ChangeData.Factory changeDataFactory,
+      ApprovalsUtil approvalsUtil,
       @Assisted RefControl refControl,
       @Assisted ChangeNotes notes) {
     this.changeDataFactory = changeDataFactory;
+    this.approvalsUtil = approvalsUtil;
     this.refControl = refControl;
     this.notes = notes;
   }
@@ -128,7 +133,7 @@ public class ChangeControl {
     if (getUser().equals(who)) {
       return this;
     }
-    return new ChangeControl(changeDataFactory,
+    return new ChangeControl(changeDataFactory, approvalsUtil,
         getRefControl().forUser(who), notes);
   }
 
@@ -190,13 +195,13 @@ public class ChangeControl {
   }
 
   /** Can this user abandon this change? */
-  public boolean canAbandon() {
+  public boolean canAbandon(ReviewDb db) throws OrmException {
-    return isOwner() // owner (aka creator) of the change can abandon
+    return (isOwner() // owner (aka creator) of the change can abandon
         || getRefControl().isOwner() // branch owner can abandon
         || getProjectControl().isOwner() // project owner can abandon
         || getUser().getCapabilities().canAdministrateServer() // site administers are god
         || getRefControl().canAbandon() // user can abandon a specific ref
-    ;
+        ) && !isPatchSetLocked(db);
   }
 
   /** Can this user publish this draft change or any draft patch set of this change? */
@@ -212,14 +217,14 @@ public class ChangeControl {
   }
 
   /** Can this user rebase this change? */
-  public boolean canRebase() {
+  public boolean canRebase(ReviewDb db) throws OrmException {
-    return isOwner() || getRefControl().canSubmit()
+    return (isOwner() || getRefControl().canSubmit()
-        || getRefControl().canRebase();
+        || getRefControl().canRebase()) && !isPatchSetLocked(db);
   }
 
   /** Can this user restore this change? */
-  public boolean canRestore() {
+  public boolean canRestore(ReviewDb db) throws OrmException {
-    return canAbandon() // Anyone who can abandon the change can restore it back
+    return canAbandon(db) // Anyone who can abandon the change can restore it back
         && getRefControl().canUpload(); // as long as you can upload too
   }
 
@@ -258,8 +263,25 @@ public class ChangeControl {
   }
 
   /** Can this user add a patch set to this change? */
-  public boolean canAddPatchSet() {
+  public boolean canAddPatchSet(ReviewDb db) throws OrmException {
-    return getRefControl().canUpload();
+    return getRefControl().canUpload() && !isPatchSetLocked(db);
+  }
+
+  /** Is the current patch set locked against state changes? */
+  public boolean isPatchSetLocked(ReviewDb db) throws OrmException {
+    if (getChange().getStatus() == Change.Status.MERGED) {
+      return false;
+    }
+
+    for (PatchSetApproval ap : approvalsUtil.byPatchSet(db, this,
+        getChange().currentPatchSetId())) {
+      LabelType type = getLabelTypes().byLabel(ap.getLabel());
+      if (type != null && ap.getValue() == 1
+          && type.getFunctionName().equalsIgnoreCase("PatchSetLock")) {
+        return true;
+      }
+    }
+    return false;
   }
 
   /** Is this user the owner of the change? */

gerrit-server/src/main/prolog/gerrit_common.pl

@@ -243,6 +243,7 @@ legacy_submit_rule('AnyWithBlock', Label, Min, Max, T) :- !, any_with_block(Labe
 legacy_submit_rule('MaxNoBlock', Label, Min, Max, T) :- !, max_no_block(Label, Max, T).
 legacy_submit_rule('NoBlock', Label, Min, Max, T) :- !, T = may(_).
 legacy_submit_rule('NoOp', Label, Min, Max, T) :- !, T = may(_).
+legacy_submit_rule('PatchSetLock', Label, Min, Max, T) :- !, T = may(_).
 legacy_submit_rule(Fun, Label, Min, Max, T) :- T = impossible(unsupported(Fun)).
 
 %% max_with_block:

gerrit-server/src/test/java/com/google/gerrit/server/project/Util.java

@@ -96,6 +96,14 @@ public class Util {
         value(-2, "This shall not be merged"));
   }
 
+  public static final LabelType patchSetLock() {
+    LabelType label = category("Patch-Set-Lock",
+        value(1, "Patch Set Locked"),
+        value(0, "Patch Set Unlocked"));
+    label.setFunctionName("PatchSetLock");
+    return label;
+  }
+
   public static LabelValue value(int value, String text) {
     return new LabelValue((short) value, text);
   }