2 files changed, 24 insertions, 6 deletions
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GCTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GCTest.java
index 8f26f7058d..bc60f64886 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GCTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GCTest.java
@@ -49,8 +49,8 @@ import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
 
 import java.io.File;
-import java.util.Collection;
 import java.io.IOException;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Date;
 import java.util.Iterator;
@@ -62,6 +62,7 @@ import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 
+import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.internal.storage.file.FileRepository;
 import org.eclipse.jgit.internal.storage.file.GC;
@@ -76,9 +77,9 @@ import org.eclipse.jgit.junit.LocalDiskRepositoryTestCase;
 import org.eclipse.jgit.junit.RepositoryTestCase;
 import org.eclipse.jgit.junit.TestRepository;
 import org.eclipse.jgit.junit.TestRepository.BranchBuilder;
-import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.junit.TestRepository.CommitBuilder;
 import org.eclipse.jgit.lib.AnyObjectId;
+import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.EmptyProgressMonitor;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Ref.Storage;
@@ -437,6 +438,20 @@ public class GCTest extends LocalDiskRepositoryTestCase {
 	}
 
 	@Test
+	public void testPackRepoWithCorruptReflog() throws Exception {
+		// create a reflog entry "0000... 0000... foobar" by doing an initial
+		// refupdate for HEAD which points to a non-existing ref. The
+		// All-Projects repo of gerrit instances had such entries
+		RefUpdate ru = repo.updateRef(Constants.HEAD);
+		ru.link("refs/to/garbage");
+		tr.branch("refs/heads/master").commit().add("A", "A").add("B", "B")
+				.create();
+		// make sure HEAD exists
+		Git.wrap(repo).checkout().setName("refs/heads/master").call();
+		gc.gc();
+	}
+
+	@Test
 	public void testKeepFiles() throws Exception {
 		BranchBuilder bb = tr.branch("refs/heads/master");
 		bb.commit().add("A", "A").add("B", "B").create();
@@ -477,9 +492,10 @@ public class GCTest extends LocalDiskRepositoryTestCase {
 		assertEquals(4, ind2.getObjectCount());
 		for (MutableEntry e: ind1)
 			if (ind2.hasObject(e.toObjectId()))
-			assertFalse(
-					"the following object is in both packfiles: "
-							+ e.toObjectId(), ind2.hasObject(e.toObjectId()));
+				assertFalse(
+						"the following object is in both packfiles: "
+								+ e.toObjectId(),
+						ind2.hasObject(e.toObjectId()));
 	}
 
 	@Test
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java
index 67bb664b5b..22fa827044 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java
@@ -555,7 +555,9 @@ public class GC {
 		for (ReflogEntry e : rlEntries) {
 			if (e.getWho().getWhen().getTime() < minTime)
 				break;
-			ret.add(e.getNewId());
+			ObjectId newId = e.getNewId();
+			if (newId != null && !ObjectId.zeroId().equals(newId))
+				ret.add(newId);
 			ObjectId oldId = e.getOldId();
 			if (oldId != null && !ObjectId.zeroId().equals(oldId))
 				ret.add(oldId);