Fix creating missing repository

When replicating to a destination where the repository does not exist,
updating the HEAD reference failed because the passed reference name was
not absolute. When this happened, an unchecked exception was triggered
but never showed in the logs. In fact, the replication logs were showing
only the message announcing the replication started, but no additional
information about the success or failure of the operation was displayed.

Avoid this by resolving symbolic references and checking the reference
is absolute before trying to update the HEAD in the new repository.

Change-Id: I18295a37a04413ba64bf7e9ee31640ee23c4c1e0

src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java b/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
index 8f61bfa..64f5152 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
@@ -401,7 +401,7 @@
     if (pool.isCreateMissingRepos()) {
       try {
         Ref head = git.exactRef(Constants.HEAD);
-        if (replicationQueue.createProject(projectName, head != null ? head.getName() : null)) {
+        if (replicationQueue.createProject(projectName, head != null ? getName(head) : null)) {
           repLog.warn("Missing repository created; retry replication to {}", uri);
           pool.reschedule(this, Destination.RetryReason.REPOSITORY_MISSING);
         } else {
@@ -422,6 +422,14 @@
     }
   }
 
+  private String getName(Ref ref) {
+    Ref target = ref;
+    while (target.isSymbolic()) {
+      target = target.getTarget();
+    }
+    return target.getName();
+  }
+
   private void runImpl() throws IOException {
     PushResult res;
     try (Transport tn = Transport.open(git, uri)) {

src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationQueue.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationQueue.java b/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationQueue.java
index 0f367aa..57893d8 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationQueue.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationQueue.java
@@ -250,7 +250,7 @@
     try (Repository repo = new FileRepository(uri.getPath())) {
       repo.create(true /* bare */);
 
-      if (head != null) {
+      if (head != null && head.startsWith(Constants.R_REFS)) {
         RefUpdate u = repo.updateRef(Constants.HEAD);
         u.disableRefLog();
         u.link(head);