Program: 8871
Project: 8871
Buggy source:
/** 
 * {@inheritDoc}
 */
@Override public SyncResult sync(@Nonnull String id) throws SyncException {
  try {
    DebugTimer timer=new DebugTimer();
    SyncResultImpl ret;
    Authorizable auth=userManager.getAuthorizable(id);
    if (auth == null) {
      return new SyncResultImpl(new SyncedIdentityImpl(id,null,false,-1),SyncResult.Status.NO_SUCH_AUTHORIZABLE);
    }
    ExternalIdentityRef ref=getIdentityRef(auth);
    if (ref == null || !idp.getName().equals(ref.getProviderName())) {
      return new SyncResultImpl(new SyncedIdentityImpl(id,null,false,-1),SyncResult.Status.FOREIGN);
    }
    if (auth instanceof Group) {
      Group group=(Group)auth;
      ExternalGroup external=idp.getGroup(id);
      timer.mark("String_Node_Str");
      if (external == null) {
        SyncedIdentityImpl syncId=createSyncedIdentity(auth);
        if (group.getDeclaredMembers().hasNext()) {
          log.info("String_Node_Str",id);
          ret=new SyncResultImpl(syncId,SyncResult.Status.NOP);
        }
 else         if (!keepMissing) {
          auth.remove();
          log.debug("String_Node_Str",id,idp.getName());
          timer.mark("String_Node_Str");
          ret=new SyncResultImpl(syncId,SyncResult.Status.DELETE);
        }
 else {
          ret=new SyncResultImpl(syncId,SyncResult.Status.MISSING);
          log.info("String_Node_Str",id);
        }
      }
 else {
        ret=syncGroup(external,group);
        timer.mark("String_Node_Str");
      }
    }
 else {
      ExternalUser external=idp.getUser(id);
      timer.mark("String_Node_Str");
      if (external == null) {
        SyncedIdentityImpl syncId=createSyncedIdentity(auth);
        if (!keepMissing) {
          auth.remove();
          log.debug("String_Node_Str",id,idp.getName());
          timer.mark("String_Node_Str");
          ret=new SyncResultImpl(syncId,SyncResult.Status.DELETE);
        }
 else {
          ret=new SyncResultImpl(syncId,SyncResult.Status.MISSING);
          log.info("String_Node_Str",id);
        }
      }
 else {
        ret=syncUser(external,(User)auth);
        timer.mark("String_Node_Str");
      }
    }
    if (log.isDebugEnabled()) {
      log.debug("String_Node_Str",id,ref.getString(),timer.getString());
    }
    return ret;
  }
 catch (  RepositoryException e) {
    throw new SyncException(e);
  }
catch (  ExternalIdentityException e) {
    throw new SyncException(e);
  }
}

Fixed version (ground truth):
/** 
 * {@inheritDoc}
 */
@Nonnull @Override public SyncResult sync(@Nonnull String id) throws SyncException {
  try {
    DebugTimer timer=new DebugTimer();
    SyncResultImpl ret;
    Authorizable auth=userManager.getAuthorizable(id);
    if (auth == null) {
      return new SyncResultImpl(new SyncedIdentityImpl(id,null,false,-1),SyncResult.Status.NO_SUCH_AUTHORIZABLE);
    }
    ExternalIdentityRef ref=getIdentityRef(auth);
    if (ref == null || !idp.getName().equals(ref.getProviderName())) {
      return new SyncResultImpl(new SyncedIdentityImpl(id,null,false,-1),SyncResult.Status.FOREIGN);
    }
    if (auth instanceof Group) {
      Group group=(Group)auth;
      ExternalGroup external=idp.getGroup(id);
      timer.mark("String_Node_Str");
      if (external == null) {
        SyncedIdentityImpl syncId=createSyncedIdentity(auth);
        if (group.getDeclaredMembers().hasNext()) {
          log.info("String_Node_Str",id);
          ret=new SyncResultImpl(syncId,SyncResult.Status.NOP);
        }
 else         if (!keepMissing) {
          auth.remove();
          log.debug("String_Node_Str",id,idp.getName());
          timer.mark("String_Node_Str");
          ret=new SyncResultImpl(syncId,SyncResult.Status.DELETE);
        }
 else {
          ret=new SyncResultImpl(syncId,SyncResult.Status.MISSING);
          log.info("String_Node_Str",id);
        }
      }
 else {
        ret=syncGroup(external,group);
        timer.mark("String_Node_Str");
      }
    }
 else {
      ExternalUser external=idp.getUser(id);
      timer.mark("String_Node_Str");
      if (external == null) {
        SyncedIdentityImpl syncId=createSyncedIdentity(auth);
        if (!keepMissing) {
          auth.remove();
          log.debug("String_Node_Str",id,idp.getName());
          timer.mark("String_Node_Str");
          ret=new SyncResultImpl(syncId,SyncResult.Status.DELETE);
        }
 else {
          ret=new SyncResultImpl(syncId,SyncResult.Status.MISSING);
          log.info("String_Node_Str",id);
        }
      }
 else {
        ret=syncUser(external,(User)auth);
        timer.mark("String_Node_Str");
      }
    }
    if (log.isDebugEnabled()) {
      log.debug("String_Node_Str",id,ref.getString(),timer.getString());
    }
    return ret;
  }
 catch (  RepositoryException e) {
    throw new SyncException(e);
  }
catch (  ExternalIdentityException e) {
    throw new SyncException(e);
  }
}