FlightSQL (CLI) & Flight ignore endpoint locations

[crepererum]

Describe the bug
The FlightSQL CLI iterates over the endpoints in FlightInfo:

arrow-rs/arrow-flight/src/bin/flight_sql_client.rs

Lines 272 to 302 in 3293a8c

	async fn execute_flight(
	client: &mut FlightSqlServiceClient<Channel>,
	info: FlightInfo,
	) -> Result<Vec<RecordBatch>> {
	let schema = Arc::new(Schema::try_from(info.clone()).context("valid schema")?);
	let mut batches = Vec::with_capacity(info.endpoint.len() + 1);
	batches.push(RecordBatch::new_empty(schema));
	info!("decoded schema");
	for endpoint in info.endpoint {
	let Some(ticket) = &endpoint.ticket else {
	bail!("did not get ticket");
	};
	let mut flight_data = client.do_get(ticket.clone()).await.context("do get")?;
	log_metadata(flight_data.headers(), "header");
	let mut endpoint_batches: Vec<_> = (&mut flight_data)
	.try_collect()
	.await
	.context("collect data stream")?;
	batches.append(&mut endpoint_batches);
	if let Some(trailers) = flight_data.trailers() {
	log_metadata(&trailers, "trailer");
	}
	}
	info!("received data");
	Ok(batches)
	}

However it only passes the ticket to DoGet, but ignores the location field of the respective endpoint.

To Reproduce
I'm not aware of system that uses different locations for GetFlightInfo and DoGet, but technically we're violating the protocol here. You could create a test server that runs on two ports and serves all but DoGet on one port and DoGet on the other, refusing the wrong method on the wrong port via an HTTP error.

Expected behavior
Use (or at least double-check) the location for the provided endpoints.

Additional context
We could fix that within the CLI code by potentially creating a new FlightSqlServiceClient if the location changed, however I think the FlightSqlServiceClient::do_get and FlightClient::do_get interface are somewhat misleading, because they suggest that you should use the same tonic::transport::Channel (and hence the same URI) for GetFlightInfo and DoGet -- which is not necessarily true. So while the bug manifests in the CLI, I think this is a Rust API bug.