Merge branch 'stable-4.1'

* stable-4.1:
  Prepare 4.1.2-SNAPSHOT builds
  JGit v4.1.1.201511131810-r
  Fallback exactRef: Do not ignore symrefs to unborn branch
  RefDirectory.exactRef: Do not ignore symrefs to unborn branch

Change-Id: I66afb303f355aad8a7eaa7a6dff06de70ae9c490
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/RefDirectoryTest.java

@@ -1024,6 +1024,25 @@ public class RefDirectoryTest extends LocalDiskRepositoryTestCase {
 		assertNull(refdir.getRef("v1.0"));
 	}
 
+	@Test
+	public void testExactRef_EmptyDatabase() throws IOException {
+		Ref r;
+
+		r = refdir.exactRef(HEAD);
+		assertTrue(r.isSymbolic());
+		assertSame(LOOSE, r.getStorage());
+		assertEquals("refs/heads/master", r.getTarget().getName());
+		assertSame(NEW, r.getTarget().getStorage());
+		assertNull(r.getTarget().getObjectId());
+
+		assertNull(refdir.exactRef("refs/heads/master"));
+		assertNull(refdir.exactRef("refs/tags/v1.0"));
+		assertNull(refdir.exactRef("FETCH_HEAD"));
+		assertNull(refdir.exactRef("NOT.A.REF.NAME"));
+		assertNull(refdir.exactRef("master"));
+		assertNull(refdir.exactRef("v1.0"));
+	}
+
 	@Test
 	public void testGetRef_FetchHead() throws IOException {
 		// This is an odd special case where we need to make sure we read

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java

@@ -261,6 +261,30 @@ public class RefDirectory extends RefDatabase {
 		return loose;
 	}
 
+	@Override
+	public Ref exactRef(String name) throws IOException {
+		RefList<Ref> packed = getPackedRefs();
+		Ref ref;
+		try {
+			ref = readRef(name, packed);
+			if (ref != null) {
+				ref = resolve(ref, 0, null, null, packed);
+			}
+		} catch (IOException e) {
+			if (name.contains("/") //$NON-NLS-1$
+					|| !(e.getCause() instanceof InvalidObjectIdException)) {
+				throw e;
+			}
+
+			// While looking for a ref outside of refs/ (e.g., 'config'), we
+			// found a non-ref file (e.g., a config file) instead.  Treat this
+			// as a ref-not-found condition.
+			ref = null;
+		}
+		fireRefsChanged();
+		return ref;
+	}
+
 	@Override
 	public Ref getRef(final String needle) throws IOException {
 		final RefList<Ref> packed = getPackedRefs();

org.eclipse.jgit/src/org/eclipse/jgit/lib/RefDatabase.java

@@ -239,21 +239,12 @@ public abstract class RefDatabase {
 	 * @since 4.1
 	 */
 	public Ref exactRef(String name) throws IOException {
-		int slash = name.lastIndexOf('/');
-		String prefix = name.substring(0, slash + 1);
-		String rest = name.substring(slash + 1);
-		Ref result = getRefs(prefix).get(rest);
-		if (result != null || slash != -1) {
-			return result;
+		Ref ref = getRef(name);
+		if (ref == null || !name.equals(ref.getName())) {
+			return null;
 		}
-
-		for (Ref ref : getAdditionalRefs()) {
-			if (name.equals(ref.getName())) {
 		return ref;
 	}
-		}
-		return null;
-	}
 
 	/**
 	 * Read the specified references.