[Bug] Debug trace call: FlatCallTracer set as default even if GethDebugTracerType::JsTracer is set

[loocapro]

Component

provider, rpc

What version of Alloy are you on?

v.0.7.0

Operating System

macOS (Apple Silicon)

Describe the bug

    fn js_tracer_config() -> GethDebugTracingCallOptions {
        let js_tracer = r#"
    {
        data: [],
        fault: function (log) {},
        step: function (log) {},
        result: function () {
            return this.data;
        }
    }"#
        .to_string();

        GethDebugTracingCallOptions {
            tracing_options: GethDebugTracingOptions {
                tracer: Some(GethDebugTracerType::JsTracer(js_tracer)),
                ..Default::default()
            },
            ..Default::default()
        }
    }
    
    #[tokio::test]
    async fn js_debug_trace_call() {
        let url = std::env::var("ETH_MAINNET_HTTP").expect("$ETH_MAINNET_HTTP must be set.");
        let provider = ProviderBuilder::new().on_http(url.parse().unwrap());
        let tx = TransactionRequest::default().with_input("0xdeadbeef");

        let trace = provider
            .debug_trace_call(tx.into(), BlockId::latest(), js_tracer_config())
            .await
            .unwrap();

        println!("{:?}", trace); // FlatCallTracer([])

        match trace {
            GethTrace::JS(trace) => println!("{:?}", trace),
            _ => panic!(), // panic
        }
    }

This test should return an empty GethTrace::JS but returns a GethTrace::FlatCallTracer.

@mattsse @DaniPopes any idea?

[mattsse]

I see,

this matches the untagged deserialized because this returns an empty vec

https://github.com/alloy-rs/alloy/blob/main/crates/rpc-types-trace/src/geth/mod.rs#L117-L118