Program: 167685
Project: 167685
Buggy source:
@Override public int complete(CommandContext ctx,String buffer,int cursor,List<String> candidates){
  final String originalLine=ctx.getParsedCommandLine().getOriginalLine();
  boolean skipWS;
  int wordCount;
  if (Character.isWhitespace(originalLine.charAt(0))) {
    skipWS=true;
    wordCount=0;
  }
 else {
    skipWS=false;
    wordCount=1;
  }
  int cmdStart=1;
  while (cmdStart < originalLine.length()) {
    if (skipWS) {
      if (!Character.isWhitespace(originalLine.charAt(cmdStart))) {
        skipWS=false;
        ++wordCount;
        if (wordCount == 3) {
          break;
        }
      }
    }
 else     if (Character.isWhitespace(originalLine.charAt(cmdStart))) {
      skipWS=true;
    }
    ++cmdStart;
  }
  String cmd;
  if (wordCount == 1) {
    cmd="String_Node_Str";
  }
 else   if (wordCount != 3) {
    return -1;
  }
 else {
    cmd=originalLine.substring(cmdStart);
    int i=cmd.indexOf("String_Node_Str");
    if (i > 0) {
      if (i == cmd.length() - 1) {
        cmd="String_Node_Str";
      }
 else {
        cmd=cmd.substring(i + 1);
      }
    }
  }
  int cmdResult=ctx.getDefaultCommandCompleter().complete(ctx,cmd,cmd.length(),candidates);
  if (cmdResult < 0) {
    return cmdResult;
  }
  int escapeCorrection=0;
  int start=originalLine.length() - 1 - buffer.length();
  while (start - escapeCorrection >= 0) {
    final char ch=originalLine.charAt(start - escapeCorrection);
    if (Character.isWhitespace(ch) || ch == '=') {
      break;
    }
    ++escapeCorrection;
  }
  return buffer.length() + escapeCorrection - (cmd.length() - cmdResult);
}

Fixed version (ground truth):
@Override public int complete(CommandContext ctx,String buffer,int cursor,List<String> candidates){
  final String substitutedLine=ctx.getParsedCommandLine().getSubstitutedLine();
  boolean skipWS;
  int wordCount;
  if (Character.isWhitespace(substitutedLine.charAt(0))) {
    skipWS=true;
    wordCount=0;
  }
 else {
    skipWS=false;
    wordCount=1;
  }
  int cmdStart=1;
  while (cmdStart < substitutedLine.length()) {
    if (skipWS) {
      if (!Character.isWhitespace(substitutedLine.charAt(cmdStart))) {
        skipWS=false;
        ++wordCount;
        if (wordCount == 3) {
          break;
        }
      }
    }
 else     if (Character.isWhitespace(substitutedLine.charAt(cmdStart))) {
      skipWS=true;
    }
    ++cmdStart;
  }
  String cmd;
  if (wordCount == 1) {
    cmd="String_Node_Str";
  }
 else   if (wordCount != 3) {
    return -1;
  }
 else {
    cmd=substitutedLine.substring(cmdStart);
    int i=cmd.indexOf("String_Node_Str");
    if (i > 0) {
      if (i == cmd.length() - 1) {
        cmd="String_Node_Str";
      }
 else {
        cmd=cmd.substring(i + 1);
      }
    }
  }
  int cmdResult=ctx.getDefaultCommandCompleter().complete(ctx,cmd,cmd.length(),candidates);
  if (cmdResult < 0) {
    return cmdResult;
  }
  int escapeCorrection=0;
  int start=substitutedLine.length() - 1 - buffer.length();
  while (start - escapeCorrection >= 0) {
    final char ch=substitutedLine.charAt(start - escapeCorrection);
    if (Character.isWhitespace(ch) || ch == '=') {
      break;
    }
    ++escapeCorrection;
  }
  return buffer.length() + escapeCorrection - (cmd.length() - cmdResult);
}