RefDirectory.delete: Prevent failures when packed-refs is outdated

The in-memory copy of packed refs might be outdated by the time the
packed-refs lock is acquired, so ensure the one read from disk is
used after acquiring the lock to prevent commit packed-refs from
throwing an exception. As a side-effect, since this updates the
in-memory copy of packed-refs when it is re-read from disk, it can
prevent other callers needing to re-read if it had changed.

Change-Id: I724c866b330b397e955b5eb04b259eedd9911e93
Signed-off-by: Kaushik Lingarkar <quic_kaushikl@quicinc.com>

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

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java
index 32eb067..aa3989e 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java
@@ -673,16 +673,16 @@ void delete(RefDirectoryUpdate update) throws IOException {
 		// Write the packed-refs file using an atomic update. We might
 		// wind up reading it twice, before and after the lock, to ensure
 		// we don't miss an edit made externally.
-		final PackedRefList packed = getPackedRefs();
+		PackedRefList packed = getPackedRefs();
 		if (packed.contains(name)) {
 			inProcessPackedRefsLock.lock();
 			try {
 				LockFile lck = lockPackedRefsOrThrow();
 				try {
-					PackedRefList cur = readPackedRefs();
-					int idx = cur.find(name);
+					packed = refreshPackedRefs();
+					int idx = packed.find(name);
 					if (0 <= idx) {
-						commitPackedRefs(lck, cur.remove(idx), packed, true);
+						commitPackedRefs(lck, packed.remove(idx), packed, true);
 					}
 				} finally {
 					lck.unlock();