Use full branch name when getting ref in BranchTrackingStatus

In case there is both a tag and branch called "foo", the tag is returned
if calling getRef with the short name. By using refs/heads/foo, the
branch is returned.

Bug: 417158
Change-Id: I86b4f83955586bb24774fd621f5012499cf67909
Signed-off-by: Robin Stocker <robin@nibor.org>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/lib/BranchTrackingStatus.java

@@ -70,8 +70,10 @@ public class BranchTrackingStatus {
 	public static BranchTrackingStatus of(Repository repository, String branchName)
 			throws IOException {
 
+		String shortBranchName = Repository.shortenRefName(branchName);
+		String fullBranchName = Constants.R_HEADS + shortBranchName;
 		BranchConfig branchConfig = new BranchConfig(repository.getConfig(),
-				branchName);
+				shortBranchName);
 
 		String trackingBranch = branchConfig.getTrackingBranch();
 		if (trackingBranch == null)
@@ -81,7 +83,7 @@ public class BranchTrackingStatus {
 		if (tracking == null)
 			return null;
 
-		Ref local = repository.getRef(branchName);
+		Ref local = repository.getRef(fullBranchName);
 		if (local == null)
 			return null;