Program: 85723
Project: 85723
Buggy source:
public ASTCssNode importEncountered(Import node,LessSource source){
  String filename=conversionUtils.extractFilename(node.getUrlExpression(),problemsHandler,configuration);
  if (filename == null) {
    problemsHandler.errorWrongImport(node.getUrlExpression());
    return null;
  }
  String urlParams="String_Node_Str";
  int paramsIndx=filename.lastIndexOf("String_Node_Str");
  if (paramsIndx != -1) {
    urlParams=filename.substring(paramsIndx);
    filename=filename.substring(0,paramsIndx);
  }
  if (!node.isInline() && treatAsCss(node,filename))   return null;
  filename=addLessSuffixIfNeeded(filename,urlParams);
  LessSource importedSource;
  try {
    importedSource=source.relativeSource(filename);
  }
 catch (  FileNotFound ex) {
    problemsHandler.errorFileNotFound(node,filename);
    return null;
  }
catch (  CannotReadFile e) {
    problemsHandler.errorFileCanNotBeRead(node,filename);
    return null;
  }
catch (  StringSourceException ex) {
    problemsHandler.warnLessImportNoBaseDirectory(node.getUrlExpression());
    return null;
  }
  if (isImportOnce(node) && alreadyVisited(importedSource)) {
    astManipulator.removeFromBody(node);
    return null;
  }
  importedSources.add(importedSource);
  String importedContent;
  try {
    importedContent=importedSource.getContent();
  }
 catch (  FileNotFound e) {
    problemsHandler.errorFileNotFound(node,filename);
    return null;
  }
catch (  CannotReadFile e) {
    problemsHandler.errorFileCanNotBeRead(node,filename);
    return null;
  }
  if (node.isInline()) {
    HiddenTokenAwareTree underlyingStructure=node.getUnderlyingStructure();
    StyleSheet result=new StyleSheet(underlyingStructure);
    InlineContent content=new InlineContent(underlyingStructure,importedContent);
    result.addMember(content);
    result.configureParentToAllChilds();
    astManipulator.replaceInBody(node,content);
    return result;
  }
  StyleSheet importedAst=buildImportedAst(node,importedSource,importedContent);
  if (node.isReferenceOnly() || node.isSilent()) {
    astManipulator.setTreeSilentness(importedAst,true);
  }
  astManipulator.replaceInBody(node,importedAst.getChilds());
  return importedAst;
}

Fixed version (ground truth):
public ASTCssNode importEncountered(Import node,LessSource source){
  String filename=conversionUtils.extractFilename(node.getUrlExpression(),problemsHandler,configuration);
  if (filename == null) {
    problemsHandler.errorWrongImport(node.getUrlExpression());
    return null;
  }
  String urlParams="String_Node_Str";
  int paramsIndx=filename.lastIndexOf("String_Node_Str");
  if (paramsIndx != -1) {
    urlParams=filename.substring(paramsIndx);
    filename=filename.substring(0,paramsIndx);
  }
  if (!node.isInline() && treatAsCss(node,filename))   return null;
  filename=addLessSuffixIfNeeded(filename,urlParams);
  LessSource importedSource;
  try {
    importedSource=source.relativeSource(filename);
  }
 catch (  FileNotFound ex) {
    problemsHandler.errorFileNotFound(node,filename);
    return null;
  }
catch (  CannotReadFile e) {
    problemsHandler.errorFileCanNotBeRead(node,filename);
    return null;
  }
catch (  StringSourceException ex) {
    problemsHandler.warnLessImportNoBaseDirectory(node.getUrlExpression());
    return null;
  }
  if (isImportOnce(node) && alreadyVisited(importedSource)) {
    astManipulator.removeFromBody(node);
    return null;
  }
  String importedContent;
  try {
    importedContent=importedSource.getContent();
    importedSources.add(importedSource);
  }
 catch (  FileNotFound e) {
    problemsHandler.errorFileNotFound(node,filename);
    return null;
  }
catch (  CannotReadFile e) {
    problemsHandler.errorFileCanNotBeRead(node,filename);
    return null;
  }
  if (node.isInline()) {
    HiddenTokenAwareTree underlyingStructure=node.getUnderlyingStructure();
    StyleSheet result=new StyleSheet(underlyingStructure);
    InlineContent content=new InlineContent(underlyingStructure,importedContent);
    result.addMember(content);
    result.configureParentToAllChilds();
    astManipulator.replaceInBody(node,content);
    return result;
  }
  StyleSheet importedAst=buildImportedAst(node,importedSource,importedContent);
  if (node.isReferenceOnly() || node.isSilent()) {
    astManipulator.setTreeSilentness(importedAst,true);
  }
  astManipulator.replaceInBody(node,importedAst.getChilds());
  return importedAst;
}