grpc encoding_error ai_generated true

INTERNAL: grpc: protobuf unknown field encountered: field number 12345

ID: grpc/grpc-protobuf-unknown-field

Also available as: JSON · Markdown · 中文
90%Fix Rate
85%Confidence
1Evidence
2024-02-20First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
protobuf 25.3 active
grpc-go 1.62.0 active
grpc-java 1.60.0 active
buf 1.28.0 active

Root Cause

Server received a protobuf message containing a field number that is not defined in the .proto schema, often due to version mismatch between client and server.

generic

中文

服务器收到包含 .proto 模式中未定义的字段编号的 protobuf 消息,通常是由于客户端和服务器之间的版本不匹配。

Official Documentation

https://protobuf.dev/programming-guides/field_presence/

Workarounds

  1. 90% success Synchronize the .proto files between client and server. Run: buf breaking --against .git to detect breaking changes. Regenerate code for both sides: protoc --go_out=. --go-grpc_out=. *.proto Or use Buf to manage versioning: buf generate --template buf.gen.yaml
    Synchronize the .proto files between client and server. Run:
      buf breaking --against .git
      to detect breaking changes. Regenerate code for both sides:
      protoc --go_out=. --go-grpc_out=. *.proto
      Or use Buf to manage versioning:
      buf generate --template buf.gen.yaml
  2. 80% success If the unknown field is intentional (e.g., forward compatibility), use protojson or custom parsing to explicitly handle unknown fields. In gRPC-Go, set: import "google.golang.org/protobuf/encoding/protojson" opts := protojson.MarshalOptions{AllowPartial: true} But prefer updating the schema to include the field.
    If the unknown field is intentional (e.g., forward compatibility), use protojson or custom parsing to explicitly handle unknown fields. In gRPC-Go, set:
      import "google.golang.org/protobuf/encoding/protojson"
      opts := protojson.MarshalOptions{AllowPartial: true}
      But prefer updating the schema to include the field.

中文步骤

  1. Synchronize the .proto files between client and server. Run:
      buf breaking --against .git
      to detect breaking changes. Regenerate code for both sides:
      protoc --go_out=. --go-grpc_out=. *.proto
      Or use Buf to manage versioning:
      buf generate --template buf.gen.yaml
  2. If the unknown field is intentional (e.g., forward compatibility), use protojson or custom parsing to explicitly handle unknown fields. In gRPC-Go, set:
      import "google.golang.org/protobuf/encoding/protojson"
      opts := protojson.MarshalOptions{AllowPartial: true}
      But prefer updating the schema to include the field.

Dead Ends

Common approaches that don't work:

  1. 70% fail

    This hides the symptom but does not fix the root cause; data loss may occur if important fields are ignored.

  2. 85% fail

    Unknown field handling is a proto3 feature; older versions may still reject or silently drop fields, leading to data corruption.