Possible fix for federation branch mirroring issue (issue 86)

src/com/gitblit/FederationPullExecutor.java

@@ -33,10 +33,6 @@ import java.util.Properties;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 
-import org.eclipse.jgit.api.Git;
-import org.eclipse.jgit.api.ResetCommand;
-import org.eclipse.jgit.api.ResetCommand.ResetType;
-import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.lib.StoredConfig;
 import org.eclipse.jgit.revwalk.RevCommit;
@@ -243,25 +239,28 @@ public class FederationPullExecutor implements Runnable {
 				if (registration.mirror) {
 					// mirror
 					if (fetched) {
-						// find the first branch name that FETCH_HEAD points to
-						List<RefModel> refs = JGitUtils.getAllRefs(r).get(commit.getId());
-						if (!ArrayUtils.isEmpty(refs)) {
-							for (RefModel ref : refs) {
-								if (ref.displayName.startsWith(org.eclipse.jgit.lib.Constants.R_REMOTES)) {
-									newFetchHead = ref.displayName;
-									break;
-								}
+						// update local branches to match the remote tracking branches
+						for (RefModel ref : JGitUtils.getRemoteBranches(r, false, -1)) {
+							if (ref.displayName.startsWith("origin/")) {
+								String branch = org.eclipse.jgit.lib.Constants.R_HEADS
+										+ ref.displayName.substring(ref.displayName.indexOf('/') + 1);
+								String hash = ref.getReferencedObjectId().getName();
+								
+								JGitUtils.setBranchRef(r, branch, hash);
+								logger.info(MessageFormat.format("     resetting {0} of {1} to {2}", branch,
+										repository.name, hash));
 							}
 						}
-						// reset HEAD to the FETCH_HEAD branch.
-						// if no branch was found, reset HEAD to the commit id.
-						Git git = new Git(r);
-						ResetCommand reset = git.reset();
-						reset.setMode(ResetType.SOFT);
-						reset.setRef(newFetchHead);
-						Ref ref = reset.call();
+						
+						String newHead;
+						if (StringUtils.isEmpty(repository.HEAD)) {
+							newHead = newFetchHead;
+						} else {
+							newHead = repository.HEAD;
+						}
+						JGitUtils.setHEADtoRef(r, newHead);
 						logger.info(MessageFormat.format("     resetting HEAD of {0} to {1}",
-								repository.name, ref.getObjectId().getName()));
+								repository.name, newHead));
 						registration.updateStatus(repository, FederationPullStatus.MIRRORED);
 					} else {
 						// indicate no commits pulled

src/com/gitblit/utils/JGitUtils.java

@@ -1222,6 +1222,74 @@ public class JGitUtils {
 		return false;
 	}
 	
+	/**
+	 * Sets the local branch ref to point to the specified commit id.
+	 *
+	 * @param repository
+	 * @param branch
+	 * @param commitId
+	 * @return true if successful
+	 */
+	public static boolean setBranchRef(Repository repository, String branch, String commitId) {
+		String branchName = branch;
+		if (!branchName.startsWith(Constants.R_HEADS)) {
+			branchName = Constants.R_HEADS + branch;
+		}
+
+		try {
+			RefUpdate refUpdate = repository.updateRef(branchName, false);
+			refUpdate.setNewObjectId(ObjectId.fromString(commitId));
+			RefUpdate.Result result = refUpdate.forceUpdate();
+
+			switch (result) {
+			case NEW:
+			case FORCED:
+			case NO_CHANGE:
+			case FAST_FORWARD:
+				return true;				
+			default:
+				LOGGER.error(MessageFormat.format("{0} {1} update to {2} returned result {3}",
+						repository.getDirectory().getAbsolutePath(), branchName, commitId, result));
+			}
+		} catch (Throwable t) {
+			error(t, repository, "{0} failed to set {1} to {2}", branchName, commitId);
+		}
+		return false;
+	}
+	
+	/**
+	 * Deletes the specified branch ref.
+	 *  
+	 * @param repository
+	 * @param branch
+	 * @return true if successful
+	 */
+	public static boolean deleteBranchRef(Repository repository, String branch) {
+		String branchName = branch;
+		if (!branchName.startsWith(Constants.R_HEADS)) {
+			branchName = Constants.R_HEADS + branch;
+		}
+
+		try {
+			RefUpdate refUpdate = repository.updateRef(branchName, false);
+			refUpdate.setForceUpdate(true);
+			RefUpdate.Result result = refUpdate.delete();
+			switch (result) {
+			case NEW:
+			case FORCED:
+			case NO_CHANGE:
+			case FAST_FORWARD:
+				return true;				
+			default:
+				LOGGER.error(MessageFormat.format("{0} failed to delete to {1} returned result {2}",
+						repository.getDirectory().getAbsolutePath(), branchName, result));
+			}
+		} catch (Throwable t) {
+			error(t, repository, "{0} failed to delete {1}", branchName);
+		}
+		return false;
+	}
+	
 	/**
 	 * Get the full branch and tag ref names for any potential HEAD targets.
 	 *

tests/com/gitblit/tests/JGitUtilsTest.java

@@ -235,6 +235,25 @@ public class JGitUtilsTest {
 		repository.close();
 	}
 
+	@Test
+	public void testRelinkBranch() throws Exception {
+		Repository repository = GitBlitSuite.getJGitRepository();
+		
+		// create/set the branch
+		JGitUtils.setBranchRef(repository, "refs/heads/reftest", "3b358ce514ec655d3ff67de1430994d8428cdb04");
+		assertEquals(1, JGitUtils.getAllRefs(repository).get(ObjectId.fromString("3b358ce514ec655d3ff67de1430994d8428cdb04")).size());
+		assertEquals(null, JGitUtils.getAllRefs(repository).get(ObjectId.fromString("755dfdb40948f5c1ec79e06bde3b0a78c352f27f")));
+		
+		// reset the branch
+		JGitUtils.setBranchRef(repository, "refs/heads/reftest", "755dfdb40948f5c1ec79e06bde3b0a78c352f27f");
+		assertEquals(null, JGitUtils.getAllRefs(repository).get(ObjectId.fromString("3b358ce514ec655d3ff67de1430994d8428cdb04")));
+		assertEquals(1, JGitUtils.getAllRefs(repository).get(ObjectId.fromString("755dfdb40948f5c1ec79e06bde3b0a78c352f27f")).size());
+
+		// delete the branch
+		assertTrue(JGitUtils.deleteBranchRef(repository, "refs/heads/reftest"));
+		repository.close();
+	}
+
 	@Test
 	public void testCreateOrphanedBranch() throws Exception {
 		Repository repository = JGitUtils.createRepository(GitBlitSuite.REPOSITORIES, "orphantest");