go runtime_error ai_generated true

panic: proto: Marshal called with nil

ID: go/proto-nil-message-fields

Also available as: JSON · Markdown · 中文
80%Fix Rate
89%Confidence
0Evidence
2024-01-22First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
google.golang.org/protobuf 1.28+ active — — —

Root Cause

proto.Marshal was called with a nil *Message pointer. This happens when an uninitialized message field or a nil response is passed directly to Marshal.

generic

中文

调用 proto.Marshal 时传入了 nil 的 *Message 指针。当未初始化的消息字段或 nil 响应直接传给 Marshal 时发生。

Workarounds

  1. 95% success 
    Guard against nil before marshalling:
if msg == nil {
    return nil, status.Error(codes.Internal, "nil message")
}
b, err := proto.Marshal(msg)
if err != nil { return nil, err }
  2. 90% success 
    Initialize nested message fields with proto message constructors instead of leaving them nil:
resp := &pb.Response{Data: &pb.Data{}} // not just &pb.Response{}

Dead Ends

Common approaches that don't work:

  1. 85% fail

    The nil message indicates a logic bug; swallowing the panic leaves a corrupt state and the message is never sent, causing silent data loss.

  2. 75% fail

    Marshalling an empty struct produces an empty byte slice, which downstream code interprets as a valid but empty message, corrupting semantics.