juicedata/juicefs · error · IllegalArgumentException

wrong type

Error message

wrong type

What it means

TestDFSIO.init parses the operation argument (-write, -read, -append, -clean, etc.); if the first CLI argument does not match any known TestType case, it throws IllegalArgumentException "wrong type". It is the operation-name validation gate for the benchmark.

Source

Thrown at sdk/java/src/main/java/io/juicefs/bench/TestDFSIO.java:187

    checkArgs();
    switch (testType) {
      case "-read":
        type = TestType.TEST_TYPE_READ;
        break;
      case "-write":
        type = TestType.TEST_TYPE_WRITE;
        break;
      case "-append":
        type = TestType.TEST_TYPE_APPEND;
        break;
      case "-truncate":
        type = TestType.TEST_TYPE_TRUNCATE;
        break;
      case "-clean":
        type = TestType.TEST_TYPE_CLEANUP;
        break;
      default:
        throw new IllegalArgumentException("wrong type");
    }
    if (random) {
      type = TestType.TEST_TYPE_READ_RANDOM;
    } else if (backward) {
      type = TestType.TEST_TYPE_READ_BACKWARD;
    } else if (skip) {
      type = TestType.TEST_TYPE_READ_SKIP;
    }
    int bufferSizeBytes = (int) parseSize(bufferSize);
    long sizeInBytes = parseSize(size);
    long skipSizeInBytes = skipSize == null ? 0 : parseSize(skipSize);
    if (type == TestType.TEST_TYPE_READ_BACKWARD) {
      skipSizeInBytes = -bufferSizeBytes;
    } else if (type == TestType.TEST_TYPE_READ_SKIP && skipSizeInBytes == 0) {
      skipSizeInBytes = bufferSizeBytes;
    }

    config.setInt("test.io.file.buffer.size", bufferSizeBytes);

View on GitHub (pinned to c9a67b23e8)

Solutions

1. Pass the operation as the first argument with exact spelling: -write, -read, -append, -clean, -truncate (check the switch in init for the supported set).
2. Order arguments so the operation flag comes first, before -size/-numberOfFiles etc.
3. Run without args to print usage and copy the accepted values verbatim.
4. Wrap parsing in your scripts to validate the op against a whitelist before launching.

Example fix

// before
TestDFSIO write -size 1GB   // -> wrong type
// after
TestDFSIO -write -size 1GB

java.util.Set<String> OPS = java.util.Set.of("-write","-read","-append","-clean","-truncate");
if (args.length == 0 || !OPS.contains(args[0])) {
  throw new IllegalArgumentException("first arg must be one of " + OPS);
}

try {
  runTestDFSIO(args);
} catch (IllegalArgumentException e) {
  if ("wrong type".equals(e.getMessage())) {
    throw new IllegalArgumentException("operation must be exactly -write|-read|-append|-clean|-truncate", e);
  }
  throw e;
}

When it happens

Trigger: Invoking TestDFSIO with a missing or misspelled first argument (e.g. 'TestDFSIO writes -size 1GB', 'Write' capitalized differently, empty arg), falling into the default branch of the switch.

Common situations: Script typos when running benchmarks against JuiceFS; passing options before the operation argument; assuming lowercase forms like 'write' vs the exact '-write' spelling accepted.

Understand the failure class

Background: "Unknown argument", "Invalid value", and "must be one of": invalid CLI argument errors explained — this error's family across 35 libraries.

Related errors

• Unsupported ByteMultiple " + sMultiple
• random, backward, skip are only valid under read
• random, backward, skip are mutually exclusive
• Cannot get file system.
• The directory item limit of " + controlDir + "

AI-assisted analysis of juicedata/juicefs@c9a67b23e8 (2026-09-06). Data as JSON: /api/errors/8ff8dd9f000f8f2b. Report an issue: GitHub.