diff --git a/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/test/resources/pack-cbdeda40019ae0e6e789088ea0f51f164f489d14.corrupt.rev b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/test/resources/pack-cbdeda40019ae0e6e789088ea0f51f164f489d14.corrupt.rev
new file mode 100644
index 000000000..74283a2f9
Binary files /dev/null and b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/test/resources/pack-cbdeda40019ae0e6e789088ea0f51f164f489d14.corrupt.rev differ
diff --git a/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/test/resources/pack-cbdeda40019ae0e6e789088ea0f51f164f489d14.rev b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/test/resources/pack-cbdeda40019ae0e6e789088ea0f51f164f489d14.rev
new file mode 100644
index 000000000..6ac7d65f6
Binary files /dev/null and b/org.eclipse.jgit.test/tst-rsrc/org/eclipse/jgit/test/resources/pack-cbdeda40019ae0e6e789088ea0f51f164f489d14.rev differ
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/PackReverseIndexTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/PackReverseIndexTest.java
index 84fc58e05..f8fb4c15e 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/PackReverseIndexTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/PackReverseIndexTest.java
@@ -10,13 +10,52 @@
 package org.eclipse.jgit.internal.storage.file;
 
 import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
 
 import java.io.ByteArrayInputStream;
+import java.io.File;
 import java.io.IOException;
 
+import org.eclipse.jgit.internal.storage.pack.PackExt;
+import org.eclipse.jgit.junit.JGitTestUtil;
 import org.junit.Test;
 
 public class PackReverseIndexTest {
+
+	@Test
+	public void open_fallbackToComputed() throws IOException {
+		String noRevFilePrefix = "pack-3280af9c07ee18a87705ef50b0cc4cd20266cf12.";
+		PackReverseIndex computed = PackReverseIndexFactory.openOrCompute(
+				getResourceFileFor(noRevFilePrefix, PackExt.REVERSE_INDEX), 7,
+				() -> PackIndex.open(
+						getResourceFileFor(noRevFilePrefix, PackExt.INDEX)));
+
+		assertTrue(computed instanceof PackReverseIndexComputed);
+	}
+
+	@Test
+	public void open_readGoodFile() throws IOException {
+		String hasRevFilePrefix = "pack-cbdeda40019ae0e6e789088ea0f51f164f489d14.";
+		PackReverseIndex version1 = PackReverseIndexFactory.openOrCompute(
+				getResourceFileFor(hasRevFilePrefix, PackExt.REVERSE_INDEX), 6,
+				() -> PackIndex.open(
+						getResourceFileFor(hasRevFilePrefix, PackExt.INDEX)));
+
+		assertTrue(version1 instanceof PackReverseIndexV1);
+	}
+
+	@Test
+	public void open_readCorruptFile() {
+		String hasRevFilePrefix = "pack-cbdeda40019ae0e6e789088ea0f51f164f489d14.";
+
+		assertThrows(IOException.class,
+				() -> PackReverseIndexFactory.openOrCompute(
+						getResourceFileFor(hasRevFilePrefix + "corrupt.",
+								PackExt.REVERSE_INDEX),
+						6, () -> PackIndex.open(getResourceFileFor(
+								hasRevFilePrefix, PackExt.INDEX))));
+	}
+
 	@Test
 	public void read_badMagic() {
 		byte[] badMagic = new byte[] { 'R', 'B', 'A', 'D', // magic
@@ -53,4 +92,9 @@ public void read_unsupportedVersion2() {
 		assertThrows(IOException.class,
 				() -> PackReverseIndexFactory.readFromFile(in, 0, () -> null));
 	}
+
+	private File getResourceFileFor(String packFilePrefix, PackExt ext) {
+		return JGitTestUtil
+				.getTestResourceFile(packFilePrefix + ext.getExtension());
+	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackReverseIndexFactory.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackReverseIndexFactory.java
index b16da5ae8..32830c3cf 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackReverseIndexFactory.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackReverseIndexFactory.java
@@ -14,6 +14,8 @@
 import static org.eclipse.jgit.internal.storage.file.PackReverseIndex.VERSION_1;
 
 import java.io.DataInput;
+import java.io.File;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.security.DigestInputStream;
@@ -23,11 +25,42 @@
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.util.IO;
+import org.eclipse.jgit.util.io.SilentFileInputStream;
 
 /**
  * Factory for creating instances of {@link PackReverseIndex}.
  */
 public final class PackReverseIndexFactory {
+	/**
+	 * Create an in-memory pack reverse index by reading it from the given file
+	 * if the file exists, or computing it from the given pack index if the file
+	 * doesn't exist.
+	 *
+	 * @param idxFile
+	 *            the file to read the pack file from, if it exists
+	 * @param objectCount
+	 *            the number of objects in the corresponding pack
+	 * @param packIndexSupplier
+	 *            a function to lazily get the corresponding forward index
+	 * @return the reverse index instance
+	 * @throws IOException
+	 *             if reading from the file fails
+	 */
+	static PackReverseIndex openOrCompute(File idxFile, long objectCount,
+			PackBitmapIndex.SupplierWithIOException<PackIndex> packIndexSupplier)
+			throws IOException {
+		try (SilentFileInputStream fd = new SilentFileInputStream(idxFile)) {
+			return readFromFile(fd, objectCount, packIndexSupplier);
+		} catch (FileNotFoundException e) {
+			return computeFromIndex(packIndexSupplier.get());
+		} catch (IOException e) {
+			throw new IOException(
+					MessageFormat.format(JGitText.get().unreadablePackIndex,
+							idxFile.getAbsolutePath()),
+					e);
+		}
+	}
+
 	/**
 	 * Compute an in-memory pack reverse index from the in-memory pack forward
 	 * index. This computation uses insertion sort, which has a quadratic