OpenFeign/feign · error · IOException

Mark not set

Error message

Mark not set

What it means

In CountingInputStream.reset (dropwizard-metrics5), the wrapped stream supports mark/reset and reset() was called, but mark() was never invoked first, so the recorded byte-count snapshot is the -1 sentinel and the underlying stream has no mark position to return to. This means reset() is being called without a prior mark() on this counting wrapper.

Solutions

  1. Call mark(int readlimit) on the stream before any reset()
  2. Guard reset() with markSupported() and a 'mark set' check, or track mark state explicitly
  3. Restructure reading logic so reset is only used after a valid mark
  4. If the wrapped stream never supports marking, avoid reset entirely

Example fix

// before
in.reset();
// after
in.mark(8192);
// ... read ...
in.reset();
Defensive patterns

Strategy: validation

Validate before calling

if (in.markSupported() && marked) { in.reset(); }

Try / catch

try {
  in.reset();
} catch (IOException e) {
  // mark missing; re-acquire stream
}

Prevention

When it happens

Trigger: Calling reset() on feign.metrics5 CountingInputStream before ever calling mark(readlimit).

Common situations: Retry/replay code that resets the body stream without marking first.

Related errors

AI-assisted analysis of OpenFeign/feign@e2a1e27560 (2026-09-10). Data as JSON: /api/errors/c20f5c5b623709f3. Report an issue: GitHub.

Appendix: source

Thrown at dropwizard-metrics5/src/main/java/feign/metrics5/CountingInputStream.java:88

    final long result = in.skip(n);
    count += result;
    return result;
  }

  @Override
  public synchronized void mark(int readlimit) {
    in.mark(readlimit);
    mark = count;
    // it's okay to mark even if mark isn't supported, as reset won't work
  }

  @Override
  public synchronized void reset() throws IOException {
    if (!in.markSupported()) {
      throw new IOException("Mark not supported");
    }
    if (mark == -1) {
      throw new IOException("Mark not set");
    }

    in.reset();
    count = mark;
  }
}

View on GitHub (pinned to e2a1e27560)