[Bug]: Possible panic: nil pointer dereference

[ldlb9527]

What happened?

The following code will cause a null pointer exception on the first iteration of the loop if span.TraceID has a zero value.

Steps to reproduce

https://github.com/jaegertracing/jaeger/blob/main/plugin/storage/grpc/shared/grpc_client.go#L193-L209

	var traces []*model.Trace
	var trace *model.Trace
	var traceID model.TraceID
	for received, err := stream.Recv(); !errors.Is(err, io.EOF); received, err = stream.Recv() {
		if err != nil {
			return nil, fmt.Errorf("stream error: %w", err)
		}

		for i, span := range received.Spans {
			if span.TraceID != traceID {
				trace = &model.Trace{}
				traceID = span.TraceID
				traces = append(traces, trace)
			}
			trace.Spans = append(trace.Spans, &received.Spans[i])
		}
	}

[ldlb9527]

If this is an issue, I’m willing to create a PR to fix it.

[dosubot]

Hey there, @ldlb9527! I'm here to help you with any bugs, questions, or contributions you have. Let's work together to solve any issues you encounter.

To prevent a null pointer dereference in the Jaeger grpc_client.go code when span.TraceID has a zero value, you can add a check to ensure that span.TraceID is not zero before using it. Here is the modified code snippet from the FindTraces method:

var traces []*model.Trace
var trace *model.Trace
var traceID model.TraceID
for received, err := stream.Recv(); !errors.Is(err, io.EOF); received, err = stream.Recv() {
    if err != nil {
        return nil, fmt.Errorf("stream error: %w", err)
    }

    for i, span := range received.Spans {
        if span.TraceID.IsZero() {
            continue // Skip spans with zero TraceID
        }
        if span.TraceID != traceID {
            trace = &model.Trace{}
            traceID = span.TraceID
            traces = append(traces, trace)
        }
        trace.Spans = append(trace.Spans, &received.Spans[i])
    }
}

In this code, the span.TraceID.IsZero() method is used to check if the TraceID is zero. If it is, the span is skipped, preventing any null pointer dereference issues ^[1].

It looks like this issue needs your expertise, @yurishkuro, could you take a look?

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