Program: 135401
Project: 135401
Buggy source:
private String formatMessage(IssueEvent issueEvent){
  PrettyTime pt=new PrettyTime();
  String timeString=pt.format(issueEvent.getCreatedAt());
  String actorName=issueEvent.getActor().getLogin();
  Issue issue=issueEvent.getIssue();
  String milestoneTitle="String_Node_Str";
  String message="String_Node_Str";
switch (IssueEventType.fromString(issueEvent.getEvent())) {
case Renamed:
    message=String.format("String_Node_Str",actorName,timeString);
  break;
case Milestoned:
if (issue.getMilestone() != null) {
  milestoneTitle=issue.getMilestone().getTitle();
}
message=String.format("String_Node_Str",actorName,milestoneTitle,timeString);
break;
case Demilestoned:
if (issue.getMilestone() != null) {
milestoneTitle=issue.getMilestone().getTitle();
}
message=String.format("String_Node_Str",actorName,milestoneTitle,timeString);
break;
case Labeled:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Unlabeled:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Assigned:
String assignee="String_Node_Str";
if (issue.getAssignee() != null) {
assignee=issue.getAssignee().getLogin();
}
if (actorName.equalsIgnoreCase(assignee)) {
message=String.format("String_Node_Str",assignee,timeString);
}
 else {
message=String.format("String_Node_Str",assignee,actorName,timeString);
}
break;
case Unassigned:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Closed:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Reopened:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Locked:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Unlocked:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Referenced:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Subscribed:
case Mentioned:
case Merged:
case HeadRefDeleted:
case HeadRefRestored:
default :
message=String.format("String_Node_Str",actorName,issueEvent.getEvent(),timeString);
break;
}
return message;
}

Fixed version (ground truth):
private String formatMessage(String actorName,String timeString,TurboIssueEvent issueEvent){
  String message="String_Node_Str";
switch (issueEvent.getType()) {
case Renamed:
    message=String.format("String_Node_Str",actorName,timeString);
  break;
case Milestoned:
milestonedCount++;
milestonesAdded.add(issueEvent.getMilestoneTitle());
break;
case Demilestoned:
demilestonedCount++;
milestonesRemoved.add(issueEvent.getMilestoneTitle());
break;
case Labeled:
labeledCount++;
labelsAdded.add(issueEvent.getLabelName());
break;
case Unlabeled:
unlabeledCount++;
labelsRemoved.add(issueEvent.getLabelName());
break;
case Assigned:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Unassigned:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Closed:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Reopened:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Locked:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Unlocked:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Referenced:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Subscribed:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Mentioned:
message=String.format("String_Node_Str",actorName,timeString);
break;
case Merged:
message=String.format("String_Node_Str",actorName,timeString);
break;
case HeadRefDeleted:
message=String.format("String_Node_Str",actorName,timeString);
break;
case HeadRefRestored:
message=String.format("String_Node_Str",actorName,timeString);
break;
default :
message=String.format("String_Node_Str",actorName,issueEvent.getType().toString(),timeString);
}
return message;
}