# proto: duplicate field "name" in JSON

- **ID:** `go/protobuf-json-marshal-duplicate-field`
- **Domain:** go
- **Category:** data_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The JSON input contains the same field more than once, which protojson rejects.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 1.x | active | — | — |

## Workarounds

1. **** (90% success)
   ```
   // Validate JSON before sending; use a library that enforces uniqueness.
   ```
2. **** (85% success)
   ```
   opts := protojson.UnmarshalOptions{DiscardUnknown: true}
err := opts.Unmarshal(data, msg)
   ```

## Dead Ends

- **** — Lenient parsers may not handle protobuf semantics correctly. (80% fail)
- **** — Manual removal is error-prone and not scalable. (70% fail)