Add POST /changes/{id}/revisions/{sha1}/cherrypick

Allow cherry picking of a patch set to a destination
branch using the REST Api.

Change-Id: If3a78d17e4be6d3bb06eef70d3b0e67867883d45

Documentation/rest-api-changes.txt

@@ -1680,6 +1680,57 @@ Deletes the reviewed flag of the calling user from a patch of a revision.
   HTTP/1.1 204 No Content
 ----
 
+[[cherry-pick]]
+Cherry Pick Revision
+~~~~~~~~~~~~~~~~~~~~
+[verse]
+'POST /changes/link:#change-id[\{change-id\}]/revisions/link:#revision-id[\{revision-id\}]/cherrypick'
+
+Cherry picks a revision to a destination branch.
+
+The commit message and destination branch must be provided in the request body inside a
+link:#cherrypick-input[CherryPickInput] entity.
+
+.Request
+----
+  POST /changes/myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9940/revisions/674ac754f91e64a0efb8087e59a176484bd534d1/cherrypick HTTP/1.0
+  Content-Type: application/json;charset=UTF-8
+
+  {
+    "message" : "Implementing Feature X";
+    "destination" : "release-branch";
+  }
+----
+
+As response a link:#change-info[ChangeInfo] entity is returned that
+describes the resulting cherry picked change.
+
+.Response
+----
+  HTTP/1.1 200 OK
+  Content-Disposition: attachment
+  Content-Type: application/json;charset=UTF-8
+
+  )]}'
+  {
+    "kind": "gerritcodereview#change",
+    "id": "myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9941",
+    "project": "myProject",
+    "branch": "release-branch",
+    "change_id": "I8473b95934b5732ac55d26311a706c9c2bde9941",
+    "subject": "Implementing Feature X",
+    "status": "NEW",
+    "created": "2013-02-01 09:59:32.126000000",
+    "updated": "2013-02-21 11:16:36.775000000",
+    "reviewed": true,
+    "mergeable": true,
+    "_sortkey": "0023412400000f7d",
+    "_number": 3965,
+    "owner": {
+      "name": "John Doe"
+    }
+  }
+----
 
 [[ids]]
 IDs
@@ -1733,7 +1784,6 @@ This can be:
   change ("674ac754"), at least 4 digits are required
 * a legacy numeric patch number ("1" for first patch set of the change)
 
-
 [[json-entities]]
 JSON Entities
 -------------
@@ -1883,6 +1933,18 @@ The link:rest-api.html#timestamp[timestamp] this message was posted.
 Which patchset (if any) generated this message.
 |==================================
 
+[[cherrypick-input]]
+CherryPickInput
+~~~~~~~~~~~~~~~
+The `CherryPickInput` entity contains information for cherry-picking a change to a new branch.
+
+[options="header",width="50%",cols="1,6"]
+|===========================
+|Field Name    |Description
+|`message`     |Commit message for the cherry-picked change
+|`destination` |Destination Branch
+|===========================
+
 [[comment-info]]
 CommentInfo
 ~~~~~~~~~~~

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

@@ -0,0 +1,92 @@
+// 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.server.change;
+
+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.RestModifyView;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.PatchSet;
+import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.change.CherryPick.Input;
+import com.google.gerrit.server.change.CherryPickChange;
+import com.google.gerrit.server.git.MergeException;
+import com.google.gerrit.server.project.ChangeControl;
+import com.google.gerrit.server.project.InvalidChangeOperationException;
+import com.google.gerrit.server.project.RefControl;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+
+class CherryPick implements RestModifyView<RevisionResource, Input> {
+  private final Provider<ReviewDb> dbProvider;
+  private final CherryPickChange cherryPickChange;
+  private final ChangeJson json;
+
+  static class Input {
+    String message;
+    String destination;
+  }
+
+  @Inject
+  CherryPick(Provider<ReviewDb> dbProvider, CherryPickChange cherryPickChange,
+      ChangeJson json) {
+    this.dbProvider = dbProvider;
+    this.cherryPickChange = cherryPickChange;
+    this.json = json;
+  }
+
+  @Override
+  public Object apply(RevisionResource revision, Input input)
+      throws AuthException, BadRequestException, ResourceConflictException,
+      Exception {
+    final ChangeControl control = revision.getControl();
+
+    if (input.message == null || input.message.trim().isEmpty()) {
+      throw new BadRequestException("message must be non-empty");
+    } else if (input.destination == null || input.destination.trim().isEmpty()) {
+      throw new BadRequestException("destination must be non-empty");
+    }
+
+    ReviewDb db = dbProvider.get();
+    if (!control.isVisible(db)) {
+      throw new AuthException("Cherry pick not permitted");
+    }
+
+    String refName = input.destination;
+    if (!refName.startsWith("refs/")) {
+      refName = "refs/heads/" + input.destination;
+    }
+
+    RefControl refControl = control.getProjectControl().controlForRef(refName);
+    if (!refControl.canUpload()) {
+      throw new AuthException("Not allowed to cherry pick "
+          + revision.getChange().getId().toString() + " to "
+          + input.destination);
+    }
+
+    final PatchSet.Id patchSetId = revision.getPatchSet().getId();
+    try {
+      Change.Id cherryPickedChangeId =
+          cherryPickChange.cherryPick(patchSetId, input.message,
+              input.destination, refControl);
+      return json.format(cherryPickedChangeId);
+    } catch (InvalidChangeOperationException e) {
+      throw new BadRequestException(e.getMessage());
+    } catch (MergeException  e) {
+      throw new ResourceConflictException(e.getMessage());
+    }
+  }
+}

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

@@ -0,0 +1,259 @@
+// 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.server.change;
+
+import com.google.gerrit.common.data.LabelTypes;
+import com.google.gerrit.common.errors.EmailException;
+import com.google.gerrit.reviewdb.client.Account;
+import com.google.gerrit.reviewdb.client.Branch;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.ChangeMessage;
+import com.google.gerrit.reviewdb.client.PatchSet;
+import com.google.gerrit.reviewdb.client.PatchSetInfo;
+import com.google.gerrit.reviewdb.client.Project;
+import com.google.gerrit.reviewdb.client.RevId;
+import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.ChangeUtil;
+import com.google.gerrit.server.GerritPersonIdent;
+import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.events.CommitReceivedEvent;
+import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.git.MergeException;
+import com.google.gerrit.server.git.MergeUtil;
+import com.google.gerrit.server.git.validators.CommitValidationException;
+import com.google.gerrit.server.git.validators.CommitValidators;
+import com.google.gerrit.server.patch.PatchSetInfoFactory;
+import com.google.gerrit.server.project.InvalidChangeOperationException;
+import com.google.gerrit.server.project.NoSuchChangeException;
+import com.google.gerrit.server.project.ProjectState;
+import com.google.gerrit.server.project.RefControl;
+import com.google.gerrit.server.ssh.NoSshInfo;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+
+import org.eclipse.jgit.errors.IncorrectObjectTypeException;
+import org.eclipse.jgit.errors.MissingObjectException;
+import org.eclipse.jgit.errors.RepositoryNotFoundException;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectInserter;
+import org.eclipse.jgit.lib.PersonIdent;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.RefUpdate;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.FooterKey;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
+import org.eclipse.jgit.transport.ReceiveCommand;
+import org.eclipse.jgit.util.ChangeIdUtil;
+
+import java.io.IOException;
+import java.sql.Timestamp;
+import java.util.Collections;
+import java.util.List;
+
+public class CherryPickChange {
+
+  private static final FooterKey CHANGE_ID = new FooterKey("Change-Id");
+
+  private final PatchSetInfoFactory patchSetInfoFactory;
+  private final ReviewDb db;
+  private final GitRepositoryManager gitManager;
+  private final PersonIdent myIdent;
+  private final IdentifiedUser currentUser;
+  private final CommitValidators.Factory commitValidatorsFactory;
+  private final ChangeInserter changeInserter;
+  final MergeUtil.Factory mergeUtilFactory;
+
+  @Inject
+  CherryPickChange(final PatchSetInfoFactory patchSetInfoFactory,
+      final ReviewDb db, @GerritPersonIdent final PersonIdent myIdent,
+      final GitRepositoryManager gitManager, final IdentifiedUser currentUser,
+      final CommitValidators.Factory commitValidatorsFactory,
+      final ChangeInserter changeInserter,
+      final MergeUtil.Factory mergeUtilFactory) {
+    this.patchSetInfoFactory = patchSetInfoFactory;
+    this.db = db;
+    this.gitManager = gitManager;
+    this.myIdent = myIdent;
+    this.currentUser = currentUser;
+    this.commitValidatorsFactory = commitValidatorsFactory;
+    this.changeInserter = changeInserter;
+    this.mergeUtilFactory = mergeUtilFactory;
+  }
+
+  public Change.Id cherryPick(final PatchSet.Id patchSetId,
+      final String message, final String destinationBranch,
+      final RefControl refControl) throws NoSuchChangeException,
+      EmailException, OrmException, MissingObjectException,
+      IncorrectObjectTypeException, IOException,
+      InvalidChangeOperationException, MergeException {
+
+    final Change.Id changeId = patchSetId.getParentKey();
+    final PatchSet patch = db.patchSets().get(patchSetId);
+    if (patch == null) {
+      throw new NoSuchChangeException(changeId);
+    }
+    if (destinationBranch == null || destinationBranch.length() == 0) {
+      throw new InvalidChangeOperationException(
+          "Cherry Pick: Destination branch cannot be null or empty");
+    }
+
+    Project.NameKey project = db.changes().get(changeId).getProject();
+    final Repository git;
+    try {
+      git = gitManager.openRepository(project);
+    } catch (RepositoryNotFoundException e) {
+      throw new NoSuchChangeException(changeId, e);
+    }
+
+    try {
+      CommitValidators commitValidators =
+          commitValidatorsFactory.create(refControl, new NoSshInfo(), git);
+
+      RevWalk revWalk = new RevWalk(git);
+      try {
+        Ref destRef = git.getRef(destinationBranch);
+        if (destRef == null) {
+          throw new InvalidChangeOperationException("Branch "
+              + destinationBranch + " does not exist.");
+        }
+
+        final RevCommit mergeTip = revWalk.parseCommit(destRef.getObjectId());
+
+        RevCommit commitToCherryPick =
+            revWalk.parseCommit(ObjectId.fromString(patch.getRevision().get()));
+
+        PersonIdent committerIdent =
+            currentUser.newCommitterIdent(myIdent.getWhen(),
+                myIdent.getTimeZone());
+
+        RevCommit cherryPickCommit;
+        ObjectInserter oi = git.newObjectInserter();
+        try {
+          ProjectState projectState = refControl.getProjectControl().getProjectState();
+          cherryPickCommit =
+              mergeUtilFactory.create(projectState).createCherryPickFromCommit(git, oi, mergeTip,
+                  commitToCherryPick, committerIdent, message, revWalk);
+        } finally {
+          oi.release();
+        }
+
+        if (cherryPickCommit == null) {
+          throw new MergeException(
+              "Could not create a merge commit during the cherry pick");
+        }
+
+        Change.Key changeKey;
+        final List<String> idList = cherryPickCommit.getFooterLines(CHANGE_ID);
+        if (!idList.isEmpty()) {
+          final String idStr = idList.get(idList.size() - 1).trim();
+          changeKey = new Change.Key(idStr);
+        } else {
+          final ObjectId computedChangeId =
+              ChangeIdUtil
+                  .computeChangeId(cherryPickCommit.getTree(), mergeTip,
+                      cherryPickCommit.getAuthorIdent(), myIdent, message);
+
+          changeKey = new Change.Key("I" + computedChangeId.name());
+        }
+
+        List<Change> destChanges =
+            db.changes()
+                .byBranchKey(
+                    new Branch.NameKey(db.changes().get(changeId).getProject(),
+                        destRef.getName()), changeKey).toList();
+
+        Change change;
+        if (destChanges.size() > 1) {
+          throw new InvalidChangeOperationException("Several changes with key "
+              + changeKey + " resides on the same branch. "
+              + "Cannot create a new patch set.");
+        } else if (destChanges.size() == 1) {
+          // The change key exists on the destination branch.
+          throw new InvalidChangeOperationException(
+              "Change with same change-id: " + changeKey
+                  + " already resides on the same branch. "
+                  + "Cannot create a new change.");
+        } else {
+          // Change key not found on destination branch. We can create a new
+          // change.
+          change =
+              new Change(changeKey, new Change.Id(db.nextChangeId()),
+                  currentUser.getAccountId(), new Branch.NameKey(project,
+                      destRef.getName()));
+        }
+
+        PatchSet.Id id =
+            new PatchSet.Id(change.getId(), Change.INITIAL_PATCH_SET_ID);
+        PatchSet newPatchSet = new PatchSet(id);
+        newPatchSet.setCreatedOn(new Timestamp(System.currentTimeMillis()));
+        newPatchSet.setUploader(change.getOwner());
+        newPatchSet.setRevision(new RevId(cherryPickCommit.name()));
+
+        PatchSetInfo newPatchSetInfo =
+            patchSetInfoFactory.get(cherryPickCommit, newPatchSet.getId());
+        change.setCurrentPatchSet(newPatchSetInfo);
+
+        CommitReceivedEvent commitReceivedEvent =
+            new CommitReceivedEvent(new ReceiveCommand(ObjectId.zeroId(),
+                cherryPickCommit.getId(), newPatchSet.getRefName()), refControl
+                .getProjectControl().getProject(), refControl.getRefName(),
+                cherryPickCommit, currentUser);
+
+        try {
+          commitValidators.validateForGerritCommits(commitReceivedEvent);
+        } catch (CommitValidationException e) {
+          throw new InvalidChangeOperationException(e.getMessage());
+        }
+
+        ChangeUtil.updated(change);
+
+        final RefUpdate ru = git.updateRef(newPatchSet.getRefName());
+        ru.setExpectedOldObjectId(ObjectId.zeroId());
+        ru.setNewObjectId(cherryPickCommit);
+        ru.disableRefLog();
+        if (ru.update(revWalk) != RefUpdate.Result.NEW) {
+          throw new IOException(String.format(
+              "Failed to create ref %s in %s: %s", newPatchSet.getRefName(),
+              change.getDest().getParentKey().get(), ru.getResult()));
+        }
+
+        final ChangeMessage cmsg =
+            new ChangeMessage(new ChangeMessage.Key(changeId,
+                ChangeUtil.messageUUID(db)), currentUser.getAccountId(),
+                patchSetId);
+        final StringBuilder msgBuf =
+            new StringBuilder("Patch Set " + patchSetId.get()
+                + ": Cherry Picked");
+        msgBuf.append("\n\n");
+        msgBuf.append("This patchset was cherry picked to change: "
+            + change.getKey().get());
+        cmsg.setMessage(msgBuf.toString());
+
+        LabelTypes labelTypes = refControl.getProjectControl().getLabelTypes();
+
+        changeInserter.insertChange(db, change, cmsg, newPatchSet,
+            cherryPickCommit, labelTypes, newPatchSetInfo,
+            Collections.<Account.Id> emptySet());
+
+        return change.getId();
+      } finally {
+        revWalk.release();
+      }
+    } finally {
+      git.close();
+    }
+  }
+}

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

@@ -67,6 +67,8 @@ public class Module extends RestApiModule {
     post(REVISION_KIND, "test.submit_rule").to(TestSubmitRule.class);
     post(REVISION_KIND, "test.submit_type").to(TestSubmitType.class);
 
+    post(REVISION_KIND, "cherrypick").to(CherryPick.class);
+
     child(REVISION_KIND, "drafts").to(Drafts.class);
     put(REVISION_KIND, "drafts").to(CreateDraft.class);
     get(DRAFT_KIND).to(GetDraft.class);

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

@@ -148,8 +148,9 @@ public class CherryPick extends SubmitStrategy {
     final String cherryPickCmtMsg = args.mergeUtil.createCherryPickCommitMessage(n);
 
     final CodeReviewCommit newCommit =
-        args.mergeUtil.createCherryPickFromCommit(args.repo, args.inserter, mergeTip, n,
-            cherryPickCommitterIdent, cherryPickCmtMsg, args.rw);
+        (CodeReviewCommit) args.mergeUtil.createCherryPickFromCommit(args.repo,
+            args.inserter, mergeTip, n, cherryPickCommitterIdent,
+            cherryPickCmtMsg, args.rw);
 
     if (newCommit == null) {
         return null;

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

@@ -180,8 +180,8 @@ public class MergeUtil {
     return submitter;
   }
 
-  public CodeReviewCommit createCherryPickFromCommit(Repository repo,
-      ObjectInserter inserter, CodeReviewCommit mergeTip, CodeReviewCommit originalCommit,
+  public RevCommit createCherryPickFromCommit(Repository repo,
+      ObjectInserter inserter, RevCommit mergeTip, RevCommit originalCommit,
       PersonIdent cherryPickCommitterIdent, String commitMsg, RevWalk rw)
       throws MissingObjectException, IncorrectObjectTypeException, IOException {
 
@@ -199,10 +199,8 @@ public class MergeUtil {
       mergeCommit.setMessage(commitMsg);
 
       final ObjectId id = commit(inserter, mergeCommit);
-      final CodeReviewCommit newCommit =
-          (CodeReviewCommit) rw.parseCommit(id);
 
-      return newCommit;
+      return rw.parseCommit(id);
     } else {
       return null;
     }