Program: 20079
Project: 20079
Buggy source:
public String createSubprojectVersion() throws ClientException {
  DocumentModel subproject=navigationContext.getCurrentDocument();
  if (subproject == null || !subproject.getType().equals(Subproject.DOCTYPE)) {
    outputMessage="String_Node_Str";
    return null;
  }
  DocumentModel versionedSubprojectModel=SubprojectServiceImpl.createSubprojectVersion(subproject,VersioningOption.MINOR);
  CoreSession coreSession=subproject.getCoreSession();
  String publishedSectionName=coreSession.getDocument(versionedSubprojectModel.getParentRef()).getName() + "String_Node_Str" + versionedSubprojectModel.getName()+ "String_Node_Str"+ versionedSubprojectModel.getVersionLabel();
  DocumentModel publishedSection=coreSession.createDocumentModel("String_Node_Str");
  publishedSection.setPathInfo("String_Node_Str",publishedSectionName);
  publishedSection.setPropertyValue("String_Node_Str",publishedSectionName);
  publishedSection=coreSession.createDocument(publishedSection);
  coreSession.save();
  DocumentModel versionedSubprojectProxy=coreSession.createProxy(versionedSubprojectModel.getRef(),publishedSection.getRef());
  outputMessage="String_Node_Str" + versionedSubprojectModel.getVersionLabel();
  Object[] params={versionedSubprojectModel.getVersionLabel()};
  facesMessages.add(StatusMessage.Severity.INFO,resourcesAccessor.getMessages().get("String_Node_Str"),params);
  DocumentModel publishedVersion=subproject;
  if (publishedVersion != null) {
    return navigationContext.navigateToDocument(publishedVersion,"String_Node_Str");
  }
 else {
    return null;
  }
}

Fixed version (ground truth):
public String createSubprojectVersion() throws ClientException {
  DocumentModel subproject=navigationContext.getCurrentDocument();
  if (subproject == null || !subproject.getType().equals(Subproject.DOCTYPE)) {
    outputMessage="String_Node_Str";
    return null;
  }
  DocumentModel versionedSubprojectModel=SubprojectServiceImpl.createSubprojectVersion(subproject,VersioningOption.MINOR);
  CoreSession coreSession=subproject.getCoreSession();
  String publishedSectionName=coreSession.getDocument(versionedSubprojectModel.getParentRef()).getName() + "String_Node_Str" + versionedSubprojectModel.getName()+ "String_Node_Str"+ versionedSubprojectModel.getVersionLabel();
  DocumentModel publishedSection=coreSession.createDocumentModel("String_Node_Str");
  publishedSection.setPathInfo("String_Node_Str",publishedSectionName);
  publishedSection.setPropertyValue("String_Node_Str",publishedSectionName);
  publishedSection=coreSession.createDocument(publishedSection);
  coreSession.save();
  DocumentModel versionedSubprojectProxy=coreSession.createProxy(versionedSubprojectModel.getRef(),publishedSection.getRef());
  outputMessage="String_Node_Str" + versionedSubprojectModel.getVersionLabel();
  Object[] params={versionedSubprojectModel.getVersionLabel()};
  facesMessages.add(StatusMessage.Severity.INFO,resourcesAccessor.getMessages().get("String_Node_Str"),params);
  navigationContext.invalidateCurrentDocument();
  DocumentModel publishedVersion=subproject;
  if (publishedVersion != null) {
    return navigationContext.navigateToDocument(publishedVersion,"String_Node_Str");
  }
 else {
    return null;
  }
}