stanfordnlp/CoreNLP · error · IllegalArgumentException

Need to give a pattern location with -patterns

Error message

Need to give a pattern location with -patterns

What it means

Ssurgeon's main() command-line driver requires the -patterns argument pointing at the Ssurgeon rules location. When argument parsing finishes without a pattern directory/file set, it throws IllegalArgumentException before any processing begins.

Solutions

1. Add -patterns <path> (rules file or directory) to the command line
2. Check the flag spelling and that the variable holding the path is non-empty in your script
3. Run without args / consult the usage message to see required flags

Example fix

// before
java Ssurgeon -treebank trees/ -type interactive
// after
java Ssurgeon -treebank trees/ -type interactive -patterns rules/ssurgeon-rules.xml

if (args == null || Arrays.stream(args).noneMatch(a -> a.equals("-patterns"))) {
  throw new IllegalArgumentException("-patterns is required");
}

try {
  Ssurgeon.main(args);
} catch (IllegalArgumentException e) {
  log.error("Usage: Ssurgeon -patterns <rules> ...");
}

When it happens

Trigger: Running java edu.stanford.nlp.semgraph.semgrex.ssurgeon.Ssurgeon without -patterns, or misspelling the flag so it is not consumed.

Common situations: CLI invocations copied from docs that omitted -patterns; shell scripts where the variable holding the path is empty; confusing -patterns with other flag names.

Understand the failure class

Background: "--flag is required" and "must specify" CLI errors: how missing-required-flag validation works and how to fix it — this error's family across 20 libraries.

Related errors

• args: treebankPath trainNums testNums
• Must specify input file with -input
• Parsing Ssurgeon args: unknown flag
• Unknown argument " + newArgs[argIndex]
• Bad character encoding

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/18cff00cb87632cc. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/semgraph/semgrex/ssurgeon/Ssurgeon.java:1160

  /**
   * Performs a simple test and print of a given file.
   * Usage Ssurgeon [-info infoFile] -patterns patternDir [-type interactive|testinfo]
   */
  public static void main(String[] args) {
    for (int argIndex = 0; argIndex < args.length; ++argIndex) {
      if (args[argIndex].equalsIgnoreCase("-info")) {
        argsBox.info = args[argIndex + 1];
        argIndex += 2;
      } else if (args[argIndex].equalsIgnoreCase("-patterns")) {
        argsBox.patternDirStr = args[argIndex + 1];
        argIndex += 2;
      } else if (args[argIndex].equalsIgnoreCase("-type")) {
        argsBox.type = RUNTYPE.valueOf(args[argIndex + 1]);
        argIndex += 2;
      }
    }
    if (argsBox.patternDirStr == null) {
      throw new IllegalArgumentException("Need to give a pattern location with -patterns");
    }
    argsBox.init();

    System.out.println(argsBox);
    try {
      if (argsBox.type == RUNTYPE.interactive) {
        Ssurgeon.inst().testRead(argsBox.patternDir);
      }
    } catch (Exception e) {
      log.error(e);
    }
  }

}

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