Fix ClassCastException in MergeCommandrefs/changes/60/3860/5

Test was added which reproduce the ClassCastException when ours or
theirs merge strategy is set to MergeCommand. Merger and MergeCommand
were updated in order to avoid exception.

Change-Id: I4c1284b4e80d82638d0677a05e5d38182526d196
Signed-off-by: Denys Digtiar <duemir@gmail.com>
Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>

6 files changed, 47 insertions, 51 deletions

diff --git a/org.eclipse.jgit.test/META-INF/MANIFEST.MF b/org.eclipse.jgit.test/META-INF/MANIFEST.MF
index d7f7ef1..06db49d 100644
--- a/org.eclipse.jgit.test/META-INF/MANIFEST.MF
+++ b/org.eclipse.jgit.test/META-INF/MANIFEST.MF
@@ -38,9 +38,11 @@ Import-Package: org.eclipse.jgit;version="[1.1.0,1.2.0)",
  org.eclipse.jgit.treewalk.filter;version="[1.1.0,1.2.0)",
  org.eclipse.jgit.util;version="[1.1.0,1.2.0)",
  org.eclipse.jgit.util.io;version="[1.1.0,1.2.0)",
- org.junit;version="[4.0.0,5.0.0)",
  org.hamcrest.core;version="[1.1.0,2.0.0)",
- org.hamcrest;version="[1.1.0,2.0.0)"
+ org.hamcrest;version="[1.1.0,2.0.0)",
+ org.junit;version="[4.4.0,5.0.0)",
+ org.junit.runner;version="[4.4.0,5.0.0)",
+ org.junit.experimental.theories;version="[4.4.0,5.0.0)"
 Require-Bundle: com.jcraft.jsch;bundle-version="[0.1.37,0.2.0)"
 Export-Package: org.eclipse.jgit.lib
  
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/MergeCommandTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/MergeCommandTest.java
index 7811706..1c682ca 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/MergeCommandTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/MergeCommandTest.java
@@ -62,8 +62,17 @@ import org.eclipse.jgit.merge.ResolveMerger.MergeFailureReason;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.util.FileUtils;
 import org.junit.Test;
+import org.junit.experimental.theories.DataPoints;
+import org.junit.experimental.theories.Theories;
+import org.junit.experimental.theories.Theory;
+import org.junit.runner.RunWith;
 
+@RunWith(Theories.class)
 public class MergeCommandTest extends RepositoryTestCase {
+
+	public static @DataPoints
+	MergeStrategy[] mergeStrategies = MergeStrategy.get();
+
 	@Test
 	public void testMergeInItself() throws Exception {
 		Git git = new Git(db);
@@ -161,6 +170,28 @@ public class MergeCommandTest extends RepositoryTestCase {
 		}
 	}
 
+	@Theory
+	public void testMergeSuccessAllStrategies(MergeStrategy mergeStrategy)
+			throws Exception {
+		Git git = new Git(db);
+
+		RevCommit first = git.commit().setMessage("first").call();
+		createBranch(first, "refs/heads/side");
+
+		writeTrashFile("a", "a");
+		git.add().addFilepattern("a").call();
+		git.commit().setMessage("second").call();
+
+		checkoutBranch("refs/heads/side");
+		writeTrashFile("b", "b");
+		git.add().addFilepattern("b").call();
+		git.commit().setMessage("third").call();
+
+		MergeResult result = git.merge().setStrategy(mergeStrategy)
+				.include(db.getRef(Constants.MASTER)).call();
+		assertEquals(MergeStatus.MERGED, result.getMergeStatus());
+	}
+
 	@Test
 	public void testContentMerge() throws Exception {
 		Git git = new Git(db);
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/MergeCommand.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/MergeCommand.java
index 5e77565..eca7e0b 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/api/MergeCommand.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/MergeCommand.java
@@ -71,9 +71,9 @@ import org.eclipse.jgit.lib.RefUpdate.Result;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.merge.MergeMessageFormatter;
 import org.eclipse.jgit.merge.MergeStrategy;
+import org.eclipse.jgit.merge.Merger;
 import org.eclipse.jgit.merge.ResolveMerger;
 import org.eclipse.jgit.merge.ResolveMerger.MergeFailureReason;
-import org.eclipse.jgit.merge.ThreeWayMerger;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.treewalk.FileTreeIterator;
@@ -193,8 +193,7 @@ public class MergeCommand extends GitCommand<MergeResult> {
 						commits, head);
 				repo.writeMergeCommitMsg(mergeMessage);
 				repo.writeMergeHeads(Arrays.asList(ref.getObjectId()));
-				ThreeWayMerger merger = (ThreeWayMerger) mergeStrategy
-						.newMerger(repo);
+				Merger merger = mergeStrategy.newMerger(repo);
 				boolean noProblems;
 				Map<String, org.eclipse.jgit.merge.MergeResult<?>> lowLevelResults = null;
 				Map<String, MergeFailureReason> failingPaths = null;
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/merge/Merger.java b/org.eclipse.jgit/src/org/eclipse/jgit/merge/Merger.java
index 1bfa269..55ac999 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/merge/Merger.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/merge/Merger.java
@@ -134,7 +134,7 @@ public abstract class Merger {
 	 *             one or more sources could not be read, or outputs could not
 	 *             be written to the Repository.
 	 */
-	public boolean merge(final AnyObjectId[] tips) throws IOException {
+	public boolean merge(final AnyObjectId... tips) throws IOException {
 		sourceObjects = new RevObject[tips.length];
 		for (int i = 0; i < tips.length; i++)
 			sourceObjects[i] = walk.parseAny(tips[i]);
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/merge/ThreeWayMerger.java b/org.eclipse.jgit/src/org/eclipse/jgit/merge/ThreeWayMerger.java
index 9350adf..521f896 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/merge/ThreeWayMerger.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/merge/ThreeWayMerger.java
@@ -84,7 +84,7 @@ public abstract class ThreeWayMerger extends Merger {
 	 * @param id
 	 *            common base treeish; null to automatically compute the common
 	 *            base from the input commits during
-	 *            {@link #merge(AnyObjectId, AnyObjectId)}.
+	 *            {@link #merge(AnyObjectId...)}.
 	 * @throws IncorrectObjectTypeException
 	 *             the object is not a treeish.
 	 * @throws MissingObjectException
@@ -101,33 +101,8 @@ public abstract class ThreeWayMerger extends Merger {
 		}
 	}
 
-	/**
-	 * Merge together two tree-ish objects.
-	 * <p>
-	 * Any tree-ish may be supplied as inputs. Commits and/or tags pointing at
-	 * trees or commits may be passed as input objects.
-	 *
-	 * @param a
-	 *            source tree to be combined together.
-	 * @param b
-	 *            source tree to be combined together.
-	 * @return true if the merge was completed without conflicts; false if the
-	 *         merge strategy cannot handle this merge or there were conflicts
-	 *         preventing it from automatically resolving all paths.
-	 * @throws IncorrectObjectTypeException
-	 *             one of the input objects is not a commit, but the strategy
-	 *             requires it to be a commit.
-	 * @throws IOException
-	 *             one or more sources could not be read, or outputs could not
-	 *             be written to the Repository.
-	 */
-	public boolean merge(final AnyObjectId a, final AnyObjectId b)
-			throws IOException {
-		return merge(new AnyObjectId[] { a, b });
-	}
-
 	@Override
-	public boolean merge(final AnyObjectId[] tips) throws IOException {
+	public boolean merge(final AnyObjectId... tips) throws IOException {
 		if (tips.length != 2)
 			return false;
 		return super.merge(tips);
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/notes/NoteMapMerger.java b/org.eclipse.jgit/src/org/eclipse/jgit/notes/NoteMapMerger.java
index b0965d2..b335fbe 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/notes/NoteMapMerger.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/notes/NoteMapMerger.java
@@ -55,7 +55,6 @@ import org.eclipse.jgit.lib.ObjectReader;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.merge.MergeStrategy;
 import org.eclipse.jgit.merge.Merger;
-import org.eclipse.jgit.merge.ThreeWayMergeStrategy;
 import org.eclipse.jgit.merge.ThreeWayMerger;
 import org.eclipse.jgit.treewalk.AbstractTreeIterator;
 import org.eclipse.jgit.treewalk.TreeWalk;
@@ -323,23 +322,13 @@ public class NoteMapMerger {
 		ObjectId theirsId = write(theirsList);
 		inserter.flush();
 
-		ObjectId resultTreeId;
-		if (nonNotesMergeStrategy instanceof ThreeWayMergeStrategy) {
-			ThreeWayMerger m = ((ThreeWayMergeStrategy) nonNotesMergeStrategy)
-					.newMerger(db, true);
-			m.setBase(baseId);
-			if (!m.merge(oursId, theirsId))
-				throw new NotesMergeConflictException(baseList, oursList,
-						theirsList);
-
-			resultTreeId = m.getResultTreeId();
-		} else {
-			Merger m = nonNotesMergeStrategy.newMerger(db, true);
-			if (!m.merge(new AnyObjectId[] { oursId, theirsId }))
-				throw new NotesMergeConflictException(baseList, oursList,
-						theirsList);
-			resultTreeId = m.getResultTreeId();
-		}
+		Merger m = nonNotesMergeStrategy.newMerger(db, true);
+		if (m instanceof ThreeWayMerger)
+			((ThreeWayMerger) m).setBase(baseId);
+		if (!m.merge(oursId, theirsId))
+			throw new NotesMergeConflictException(baseList, oursList,
+					theirsList);
+		ObjectId resultTreeId = m.getResultTreeId();
 		AbbreviatedObjectId none = AbbreviatedObjectId.fromString("");
 		return NoteParser.parse(none, resultTreeId, reader).nonNotes;
 	}