[Bug]: Missing parent span used in Condvar in Jaeger exports about opentelemetry-rust HOT 2 OPEN

use std::{collections::HashMap, env, process::Command};

use opentelemetry::{
    global::{self, shutdown_tracer_provider},
    trace::TraceError,
    KeyValue,
};
use opentelemetry_otlp::WithExportConfig;
use opentelemetry_sdk::{propagation::TraceContextPropagator, trace as sdktrace, Resource};
use tracing::{instrument, Span};
use tracing_opentelemetry::OpenTelemetrySpanExt;
use tracing_subscriber::{layer::SubscriberExt, Registry};

#[tokio::main]
async fn main() {
    let tracer = init_tracer().expect("Failed to initialize tracer.");
    let telemetry = tracing_opentelemetry::layer().with_tracer(tracer);
    global::set_text_map_propagator(TraceContextPropagator::new());
    let subscriber = Registry::default().with(telemetry);

    tracing::subscriber::with_default(subscriber, || {
        shim_main();
    });

    shutdown_tracer_provider();
    println!("Shutdown");
}

#[instrument]
fn shim_main() {
    let args: Vec<_> = env::args().collect();
    match args.get(1) {
        Some(arg) if arg == "1" => {
            a1();
            spawn();
        }
        Some(arg) if arg == "2" => {
            if let Some(trace_context) = env::args().nth(2) {
                let extractor: HashMap<String, String> =
                    serde_json::from_str(&trace_context).unwrap();
                let context =
                    global::get_text_map_propagator(|propagator| propagator.extract(&extractor));
                Span::current().set_parent(context);
            }
            a2();
        }
        _ => println!("Usage: {} <1|2 trace_context>", args[0]),
    }
}

#[instrument]
pub fn a1() {
    println!("a1");
}

#[instrument]
pub fn a2() {
    println!("a2");
}

#[instrument]
fn spawn() {
    let cmd = env::current_exe().unwrap();
    let cwd = env::current_dir().unwrap();
    let mut command = Command::new(cmd);

    let mut injector: HashMap<String, String> = HashMap::default();
    global::get_text_map_propagator(|propagator| {
        // We must explicitely retrieve the context from `tracing`
        propagator.inject_context(&Span::current().context(), &mut injector);
    });
    let trace_context = serde_json::to_string(&injector).unwrap();

    command.current_dir(cwd).arg("2").arg(trace_context);
    command.spawn().unwrap();
}

fn init_tracer() -> Result<opentelemetry_sdk::trace::Tracer, TraceError> {
    opentelemetry_otlp::new_pipeline()
        .tracing()
        .with_exporter(
            opentelemetry_otlp::new_exporter()
                .tonic()
                .with_endpoint("http://localhost:4317"),
        )
        .with_trace_config(
            sdktrace::config().with_resource(Resource::new(vec![KeyValue::new(
                "service.name",
                "instance3",
            )])),
        )
        .install_simple()
}