Detect stale-file-handle error in causal chain

Cover the case where the exception is wrapped up as a
cause, e.g., PackIndex#open(File).

Change-Id: I0df5b1e9c2ff886bdd84dee3658b6a50866699d1
Signed-off-by: Hongkai Liu <hongkai.liu@ericsson.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/util/FileUtilsTest.java

@@ -50,10 +50,14 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.io.UnsupportedEncodingException;
 import java.nio.file.Files;
 import java.nio.file.StandardCopyOption;
+import java.rmi.RemoteException;
 import java.util.regex.Matcher;
 
+import javax.management.remote.JMXProviderException;
+
 import org.eclipse.jgit.junit.JGitTestUtil;
 import org.junit.After;
 import org.junit.Assume;
@@ -61,6 +65,17 @@
 import org.junit.Test;
 
 public class FileUtilsTest {
+	private static final String MSG = "Stale file handle";
+
+	private static final String SOME_ERROR_MSG = "some error message";
+
+	private static final IOException IO_EXCEPTION = new UnsupportedEncodingException(
+			MSG);
+
+	private static final IOException IO_EXCEPTION_WITH_CAUSE = new RemoteException(
+			SOME_ERROR_MSG,
+			new JMXProviderException(SOME_ERROR_MSG, IO_EXCEPTION));
+
 	private File trash;
 
 	@Before
@@ -541,4 +556,29 @@ private String toOSPathString(String path) {
 		return path.replaceAll("/|\\\\",
 				Matcher.quoteReplacement(File.separator));
 	}
+
+	@Test
+	public void testIsStaleFileHandleWithDirectCause() throws Exception {
+		assertTrue(FileUtils.isStaleFileHandle(IO_EXCEPTION));
+	}
+
+	@Test
+	public void testIsStaleFileHandleWithIndirectCause() throws Exception {
+		assertFalse(
+				FileUtils.isStaleFileHandle(IO_EXCEPTION_WITH_CAUSE));
+	}
+
+	@Test
+	public void testIsStaleFileHandleInCausalChainWithDirectCause()
+			throws Exception {
+		assertTrue(
+				FileUtils.isStaleFileHandleInCausalChain(IO_EXCEPTION));
+	}
+
+	@Test
+	public void testIsStaleFileHandleInCausalChainWithIndirectCause()
+			throws Exception {
+		assertTrue(FileUtils
+				.isStaleFileHandleInCausalChain(IO_EXCEPTION_WITH_CAUSE));
+	}
 }

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

@@ -577,7 +577,7 @@ private void handlePackError(IOException e, PackFile p) {
 				warnTmpl = JGitText.get().packWasDeleted;
 			}
 			removePack(p);
-		} else if (FileUtils.isStaleFileHandle(e)) {
+		} else if (FileUtils.isStaleFileHandleInCausalChain(e)) {
 			warnTmpl = JGitText.get().packHandleIsStale;
 			removePack(p);
 		}

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

@@ -798,7 +798,8 @@ private PackedRefList readPackedRefs() throws IOException {
 				return new PackedRefList(parsePackedRefs(br), snapshot,
 						ObjectId.fromRaw(digest.digest()));
 			} catch (IOException e) {
-				if (FileUtils.isStaleFileHandle(e) && retries < maxStaleRetries) {
+				if (FileUtils.isStaleFileHandleInCausalChain(e)
+						&& retries < maxStaleRetries) {
 					if (LOG.isDebugEnabled()) {
 						LOG.debug(MessageFormat.format(
 								JGitText.get().packedRefsHandleIsStale,

org.eclipse.jgit/src/org/eclipse/jgit/util/FileUtils.java

@@ -547,6 +547,26 @@ public static boolean isStaleFileHandle(IOException ioe) {
 						.matches("stale .*file .*handle"); //$NON-NLS-1$
 	}
 
+	/**
+	 * Determine if a throwable or a cause in its causal chain is a Stale NFS
+	 * File Handle
+	 *
+	 * @param throwable
+	 * @return a boolean true if the throwable or a cause in its causal chain is
+	 *         a Stale NFS File Handle
+	 * @since 4.7
+	 */
+	public static boolean isStaleFileHandleInCausalChain(Throwable throwable) {
+		while (throwable != null) {
+			if (throwable instanceof IOException
+					&& isStaleFileHandle((IOException) throwable)) {
+				return true;
+			}
+			throwable = throwable.getCause();
+		}
+		return false;
+	}
+
 	/**
 	 * @param file
 	 * @return {@code true} if the passed file is a symbolic link