go data_error ai_generated true

proto: (line 1:15): unknown field "userName"

ID: go/proto-json-unknown-field

Also available as: JSON · Markdown · 中文
80%Fix Rate
88%Confidence
0Evidence
2024-08-14First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
google.golang.org/protobuf v1.30+ active — — —

Root Cause

protojson.Unmarshal encountered a JSON key that does not match any field in the message. By default protojson rejects unknown fields and is case-sensitive on the proto field names (camelCase or snake_case accepted).

generic

中文

protojson.Unmarshal 遇到与消息中任何字段都不匹配的 JSON 键。默认情况下 protojson 拒绝未知字段，且对 proto 字段名大小写敏感（接受 camelCase 或 snake_case）。

Workarounds

  1. 90% success 
    opts := protojson.UnmarshalOptions{DiscardUnknown: true}
err := opts.Unmarshal(data, msg)
  2. 85% success 
    // user.proto
string user_name = 1 [json_name = "userName"];

Dead Ends

Common approaches that don't work:

  1. 60% fail

    Field renames change the wire contract and require regenerating all clients; it treats a symptom, not the schema mismatch.

  2. 85% fail

    protojson returns an error and leaves the message partially populated or empty; downstream reads wrong data.