Only fetch tags that do not exist locally with auto-follow

This corresponds to what C Git does, quoting from the fetch man page:

  This is done by first fetching from the remote using the given
  <refspec>s, and if the repository has objects that are pointed by
  remote tags that it does not yet have, then fetch those missing tags.

Before, JGit would also fetch tags that exist locally but point to a
different object, resulting in REJECTED results for these.

Also add some test cases to cover more cases.

Bug: 388095
Change-Id: Ib03d2d82e9c4b60179d626cfd5174be1da6388b2
Also-by: Stefan Lay <stefan.lay@sap.com>

1 files changed, 8 insertions, 15 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchProcess.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchProcess.java
index d3e38f9c81..9a11dbda65 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchProcess.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchProcess.java
@@ -382,23 +382,16 @@ class FetchProcess {
 				continue;
 
 			Ref local = haveRefs.get(r.getName());
-			ObjectId obj = r.getObjectId();
-
-			if (r.getPeeledObjectId() == null) {
-				if (local != null && obj.equals(local.getObjectId()))
-					continue;
-				if (askFor.containsKey(obj) || transport.local.hasObject(obj))
-					wantTag(r);
-				else
-					additionalTags.add(r);
+			if (local != null)
+				// We already have a tag with this name, don't fetch it (even if
+				// the local is different).
 				continue;
-			}
 
-			if (local != null) {
-				if (!obj.equals(local.getObjectId()))
-					wantTag(r);
-			} else if (askFor.containsKey(r.getPeeledObjectId())
-					|| transport.local.hasObject(r.getPeeledObjectId()))
+			ObjectId obj = r.getPeeledObjectId();
+			if (obj == null)
+				obj = r.getObjectId();
+
+			if (askFor.containsKey(obj) || transport.local.hasObject(obj))
 				wantTag(r);
 			else
 				additionalTags.add(r);