InlineEdit: Add method to rebase change edit

Change-Id: I09bbf692bc7812df5f608fc87455aa673b9f0cf9

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/edit/BUCK

@@ -3,4 +3,5 @@ include_defs('//gerrit-acceptance-tests/tests.defs')
 acceptance_tests(
   srcs = ['ChangeEditIT.java'],
   labels = ['edit'],
+  deps = ['//lib/joda:joda-time'],
 )

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/edit/ChangeEditIT.java

@@ -15,6 +15,8 @@
 package com.google.gerrit.acceptance.edit;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.concurrent.TimeUnit.SECONDS;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -46,11 +48,16 @@ import com.google.inject.util.Providers;
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.lib.RefUpdate;
+import org.joda.time.DateTime;
+import org.joda.time.DateTimeUtils;
+import org.joda.time.DateTimeUtils.MillisProvider;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 
 import java.io.ByteArrayOutputStream;
+import java.util.Date;
+import java.util.concurrent.atomic.AtomicLong;
 
 @NoHttpd
 public class ChangeEditIT extends AbstractDaemonTest {
@@ -84,6 +91,7 @@ public class ChangeEditIT extends AbstractDaemonTest {
 
   private ReviewDb db;
   private Change change;
+  private String changeId;
   private Change change2;
   private PatchSet ps;
   private PatchSet ps2;
@@ -92,22 +100,33 @@ public class ChangeEditIT extends AbstractDaemonTest {
   @Before
   public void setUp() throws Exception {
     db = reviewDbProvider.open();
-    String changeId = newChange(git, admin.getIdent());
-    change = getChange(changeId);
+    changeId = newChange(git, admin.getIdent());
     ps = getCurrentPatchSet(changeId);
+    amendChange(git, admin.getIdent(), changeId);
+    change = getChange(changeId);
     assertNotNull(ps);
-    changeId = newChange2(git, admin.getIdent());
-    change2 = getChange(changeId);
+    String changeId2 = newChange2(git, admin.getIdent());
+    change2 = getChange(changeId2);
     assertNotNull(change2);
-    ps2 = getCurrentPatchSet(changeId);
+    ps2 = getCurrentPatchSet(changeId2);
     assertNotNull(ps2);
     session = new RestSession(server, admin);
     atrScope.set(atrScope.newContext(reviewDbProvider, sshSession,
         identifiedUserFactory.create(Providers.of(db), admin.getId())));
+    final long clockStepMs = MILLISECONDS.convert(1, SECONDS);
+    final AtomicLong clockMs = new AtomicLong(
+        new DateTime(2009, 9, 30, 17, 0, 0).getMillis());
+    DateTimeUtils.setCurrentMillisProvider(new MillisProvider() {
+      @Override
+      public long getMillis() {
+        return clockMs.getAndAdd(clockStepMs);
+      }
+    });
   }
 
   @After
   public void cleanup() {
+    DateTimeUtils.setCurrentMillisSystem();
     db.close();
   }
 
@@ -128,6 +147,21 @@ public class ChangeEditIT extends AbstractDaemonTest {
 
   @Test
   public void publishEdit() throws Exception {
+    assertEquals(RefUpdate.Result.NEW,
+        modifier.createEdit(
+            change,
+            getCurrentPatchSet(changeId)));
+    assertEquals(RefUpdate.Result.FORCED,
+        modifier.modifyFile(
+            editUtil.byChange(change).get(),
+            FILE_NAME,
+            CONTENT_NEW2));
+    editUtil.publish(editUtil.byChange(change).get());
+    assertFalse(editUtil.byChange(change).isPresent());
+  }
+
+  @Test
+  public void rebaseEdit() throws Exception {
     assertEquals(RefUpdate.Result.NEW,
         modifier.createEdit(
             change,
@@ -137,8 +171,23 @@ public class ChangeEditIT extends AbstractDaemonTest {
             editUtil.byChange(change).get(),
             FILE_NAME,
             CONTENT_NEW));
-    editUtil.publish(editUtil.byChange(change).get());
-    assertFalse(editUtil.byChange(change).isPresent());
+    ChangeEdit edit = editUtil.byChange(change).get();
+    PatchSet current = getCurrentPatchSet(changeId);
+    assertEquals(current.getPatchSetId() - 1,
+        edit.getBasePatchSet().getPatchSetId());
+    Date beforeRebase = edit.getEditCommit().getCommitterIdent().getWhen();
+    modifier.rebaseEdit(edit, current);
+    edit = editUtil.byChange(change).get();
+    assertArrayEquals(CONTENT_NEW,
+        toBytes(fileUtil.getContent(edit.getChange().getProject(),
+            edit.getRevision().get(), FILE_NAME)));
+    assertArrayEquals(CONTENT_NEW2,
+        toBytes(fileUtil.getContent(edit.getChange().getProject(),
+            edit.getRevision().get(), FILE_NAME2)));
+    assertEquals(current.getPatchSetId(),
+        edit.getBasePatchSet().getPatchSetId());
+    Date afterRebase = edit.getEditCommit().getCommitterIdent().getWhen();
+    assertFalse(beforeRebase.equals(afterRebase));
   }
 
   @Test
@@ -332,6 +381,13 @@ public class ChangeEditIT extends AbstractDaemonTest {
     return push.to(git, "refs/for/master").getChangeId();
   }
 
+  private String amendChange(Git git, PersonIdent ident, String changeId) throws Exception {
+    PushOneCommit push =
+        pushFactory.create(db, ident, PushOneCommit.SUBJECT, FILE_NAME2,
+            new String(CONTENT_NEW2), changeId);
+    return push.to(git, "refs/for/master").getChangeId();
+  }
+
   private String newChange2(Git git, PersonIdent ident) throws Exception {
     PushOneCommit push =
         pushFactory.create(db, ident, PushOneCommit.SUBJECT, FILE_NAME,

gerrit-server/src/main/java/com/google/gerrit/server/edit/ChangeEditModifier.java

@@ -46,6 +46,8 @@ import org.eclipse.jgit.lib.ObjectReader;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.lib.RefUpdate;
 import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.merge.MergeStrategy;
+import org.eclipse.jgit.merge.ThreeWayMerger;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.treewalk.TreeWalk;
@@ -126,6 +128,61 @@ public class ChangeEditModifier {
     }
   }
 
+  /**
+   * Rebase change edit on latest patch set
+   *
+   * @param edit change edit that contains edit to rebase
+   * @param current patch set to rebase the edit on
+   * @throws AuthException
+   * @throws InvalidChangeOperationException
+   * @throws IOException
+   */
+  public RefUpdate.Result rebaseEdit(ChangeEdit edit, PatchSet current)
+      throws AuthException, InvalidChangeOperationException, IOException {
+    if (!currentUser.get().isIdentifiedUser()) {
+      throw new AuthException("Authentication required");
+    }
+
+    Change change = edit.getChange();
+    IdentifiedUser me = (IdentifiedUser) currentUser.get();
+    String refName = editRefName(me.getAccountId(), change.getId());
+    Repository repo = gitManager.openRepository(change.getProject());
+    try {
+      RevWalk rw = new RevWalk(repo);
+      ObjectInserter inserter = repo.newObjectInserter();
+      try {
+        RevCommit editCommit = edit.getEditCommit();
+        RevCommit mergeTip = rw.parseCommit(ObjectId.fromString(
+            current.getRevision().get()));
+        ThreeWayMerger m = MergeStrategy.RESOLVE.newMerger(repo, true);
+        m.setObjectInserter(inserter);
+        m.setBase(editCommit.getParent(0));
+        if (m.merge(mergeTip, editCommit)) {
+          ObjectId tree = m.getResultTreeId();
+
+          CommitBuilder mergeCommit = new CommitBuilder();
+          mergeCommit.setTreeId(tree);
+          mergeCommit.setParentId(mergeTip);
+          mergeCommit.setAuthor(editCommit.getAuthorIdent());
+          mergeCommit.setCommitter(new PersonIdent(
+              editCommit.getCommitterIdent(), TimeUtil.nowTs()));
+          mergeCommit.setMessage(editCommit.getFullMessage());
+          ObjectId newEdit = inserter.insert(mergeCommit);
+          inserter.flush();
+          return update(repo, me, refName, rw, editCommit, newEdit);
+        } else {
+          // TODO(davido): Allow to resolve conflicts inline
+          throw new InvalidChangeOperationException("merge conflict");
+        }
+      } finally {
+        rw.release();
+        inserter.release();
+      }
+    } finally {
+      repo.close();
+    }
+  }
+
   /**
    * Modify file in existing change edit from its base commit.
    *