go runtime_error ai_generated true

panic: runtime error: invalid memory address or nil pointer dereference [signal SIGSEGV]

ID: go/grpc-protobuf-oneof-nil-pointer

Also available as: JSON · Markdown · 中文
80%Fix Rate
86%Confidence
0Evidence
2024-07-12First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1.0 active — — —
1.1 active — — —

Root Cause

Accessing a protobuf oneof field without checking if it is set, leading to nil pointer dereference.

generic

中文

访问protobuf oneof字段而未检查是否已设置，导致空指针解引用。

Workarounds

  1. 98% success Check if oneof field is non-nil before type assertion. 
    if v := msg.GetPayload(); v != nil {
    switch x := v.(type) {
    case *pb.Payload_Text:
        fmt.Println(x.Text)
    }
}
  2. 85% success Use proto.GetField to safely retrieve oneof values. 
    import "google.golang.org/protobuf/proto"
field := proto.GetField(msg, "payload")

Dead Ends

Common approaches that don't work:

  1. Use a type switch without nil check. 95% fail

    Oneof interface can be nil; type switch panics.

  2. Assume the oneof is always populated. 90% fail

    Unmarshal may leave it nil if field is absent.