Fix ResetCommand to return the resulting ref

ResetCommand was not returning the updated ref as a result of the call()
method. Since the ResetCommand is always updating the same ref (HEAD)
this should always be the HEAD ref.

Bug: 440750
Change-Id: I7974975c3ab05e68c208384e69cf0692ded6e8db
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/ResetCommandTest.java

 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.FileMode;
 import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.treewalk.TreeWalk;
 			AmbiguousObjectException, IOException, GitAPIException {
 		setupRepository();
 		ObjectId prevHead = db.resolve(Constants.HEAD);
-		git.reset().setMode(ResetType.HARD).setRef(initialCommit.getName())
-				.call();
+		assertSameAsHead(git.reset().setMode(ResetType.HARD)
+				.setRef(initialCommit.getName()).call());
 		// check if HEAD points to initial commit now
 		ObjectId head = db.resolve(Constants.HEAD);
 		assertEquals(initialCommit, head);
 			AmbiguousObjectException, IOException, GitAPIException {
 		setupRepository();
 		ObjectId prevHead = db.resolve(Constants.HEAD);
-		git.reset().setMode(ResetType.SOFT).setRef(initialCommit.getName())
-				.call();
+		assertSameAsHead(git.reset().setMode(ResetType.SOFT)
+				.setRef(initialCommit.getName()).call());
 		// check if HEAD points to initial commit now
 		ObjectId head = db.resolve(Constants.HEAD);
 		assertEquals(initialCommit, head);
 			AmbiguousObjectException, IOException, GitAPIException {
 		setupRepository();
 		ObjectId prevHead = db.resolve(Constants.HEAD);
-		git.reset().setMode(ResetType.MIXED).setRef(initialCommit.getName())
-				.call();
+		assertSameAsHead(git.reset().setMode(ResetType.MIXED)
+				.setRef(initialCommit.getName()).call());
 		// check if HEAD points to initial commit now
 		ObjectId head = db.resolve(Constants.HEAD);
 		assertEquals(initialCommit, head);
 		assertTrue(bEntry.getLength() > 0);
 		assertTrue(bEntry.getLastModified() > 0);
 
-		git.reset().setMode(ResetType.MIXED).setRef(commit2.getName()).call();
+		assertSameAsHead(git.reset().setMode(ResetType.MIXED)
+				.setRef(commit2.getName()).call());
 
 		cache = db.readDirCache();
 
 				+ "[a.txt, mode:100644, stage:3]",
 				indexState(0));
 
-		git.reset().setMode(ResetType.MIXED).call();
+		assertSameAsHead(git.reset().setMode(ResetType.MIXED).call());
 
 		assertEquals("[a.txt, mode:100644]" + "[b.txt, mode:100644]",
 				indexState(0));
 
 		// 'a.txt' has already been modified in setupRepository
 		// 'notAddedToIndex.txt' has been added to repository
-		git.reset().addPath(indexFile.getName())
-				.addPath(untrackedFile.getName()).call();
+		assertSameAsHead(git.reset().addPath(indexFile.getName())
+				.addPath(untrackedFile.getName()).call());
 
 		DirCacheEntry postReset = DirCache.read(db.getIndexFile(), db.getFS())
 				.getEntry(indexFile.getName());
 		git.add().addFilepattern(untrackedFile.getName()).call();
 
 		// 'dir/b.txt' has already been modified in setupRepository
-		git.reset().addPath("dir").call();
+		assertSameAsHead(git.reset().addPath("dir").call());
 
 		DirCacheEntry postReset = DirCache.read(db.getIndexFile(), db.getFS())
 				.getEntry("dir/b.txt");
 		// 'a.txt' has already been modified in setupRepository
 		// 'notAddedToIndex.txt' has been added to repository
 		// reset to the inital commit
-		git.reset().setRef(initialCommit.getName())
-				.addPath(indexFile.getName())
-				.addPath(untrackedFile.getName()).call();
+		assertSameAsHead(git.reset().setRef(initialCommit.getName())
+				.addPath(indexFile.getName()).addPath(untrackedFile.getName())
+				.call());
 
 		// check that HEAD hasn't moved
 		ObjectId head = db.resolve(Constants.HEAD);
 				+ "[b.txt, mode:100644]",
 				indexState(0));
 
-		git.reset().addPath(file).call();
+		assertSameAsHead(git.reset().addPath(file).call());
 
 		assertEquals("[a.txt, mode:100644]" + "[b.txt, mode:100644]",
 				indexState(0));
 		writeTrashFile("a.txt", "content");
 		git.add().addFilepattern("a.txt").call();
 		// Should assume an empty tree, like in C Git 1.8.2
-		git.reset().addPath("a.txt").call();
+		assertSameAsHead(git.reset().addPath("a.txt").call());
 
 		DirCache cache = db.readDirCache();
 		DirCacheEntry aEntry = cache.getEntry("a.txt");
 		git = new Git(db);
 		writeTrashFile("a.txt", "content");
 		git.add().addFilepattern("a.txt").call();
-		git.reset().setRef("doesnotexist").addPath("a.txt").call();
+		assertSameAsHead(
+				git.reset().setRef("doesnotexist").addPath("a.txt").call());
 	}
 
 	@Test
 		git.add().addFilepattern("a.txt").call();
 		writeTrashFile("a.txt", "modified");
 		// should use default mode MIXED
-		git.reset().call();
+		assertSameAsHead(git.reset().call());
 
 		DirCache cache = db.readDirCache();
 		DirCacheEntry aEntry = cache.getEntry("a.txt");
 
 		git.add().addFilepattern(untrackedFile.getName()).call();
 
-		git.reset().setRef(tagName).setMode(HARD).call();
+		assertSameAsHead(git.reset().setRef(tagName).setMode(HARD).call());
 
 		ObjectId head = db.resolve(Constants.HEAD);
 		assertEquals(secondCommit, head);
 				result.getMergeStatus());
 		assertNotNull(db.readSquashCommitMsg());
 
-		g.reset().setMode(ResetType.HARD).setRef(first.getName()).call();
+		assertSameAsHead(g.reset().setMode(ResetType.HARD)
+				.setRef(first.getName()).call());
 
 		assertNull(db.readSquashCommitMsg());
 	}
 		File fileA = writeTrashFile("a.txt", "content");
 		git.add().addFilepattern("a.txt").call();
 		// Should assume an empty tree, like in C Git 1.8.2
-		git.reset().setMode(ResetType.HARD).call();
+		assertSameAsHead(git.reset().setMode(ResetType.HARD).call());
 
 		DirCache cache = db.readDirCache();
 		DirCacheEntry aEntry = cache.getEntry("a.txt");
 		return dc.getEntry(path) != null;
 	}
 
+	/**
+	 * Asserts that a certain ref is similar to repos HEAD.
+	 * @param ref
+	 * @throws IOException
+	 */
+	private void assertSameAsHead(Ref ref) throws IOException {
+		Ref headRef = db.getRef(Constants.HEAD);
+		assertEquals(headRef.getName(), ref.getName());
+		assertEquals(headRef.getObjectId(), ref.getObjectId());
+	}
 }

org.eclipse.jgit/src/org/eclipse/jgit/api/ResetCommand.java

 				ObjectId origHead = ru.getOldObjectId();
 				if (origHead != null)
 					repo.writeOrigHead(origHead);
-				result = ru.getRef();
-			} else {
-				result = repo.getRef(Constants.HEAD);
 			}
+			result = repo.exactRef(Constants.HEAD);
 
 			if (mode == null)
 				mode = ResetType.MIXED;