req/resp: use IfDisconnected::ImmediateError (#4253)

* req/resp: use IfDisconnected::ImmediateError

* remove outdated comments

* fmt

polkadot/node/network/availability-distribution/src/pov_requester/mod.rs

@@ -64,10 +64,7 @@ where
 
 	ctx.send_message(NetworkBridgeMessage::SendRequests(
 		vec![full_req],
-		// We are supposed to be connected to validators of our group via `PeerSet`,
-		// but at session boundaries that is kind of racy, in case a connection takes
-		// longer to get established, so we try to connect in any case.
-		IfDisconnected::TryConnect,
+		IfDisconnected::ImmediateError,
 	))
 	.await;
 

polkadot/node/network/availability-distribution/src/requester/fetch_task/mod.rs

@@ -327,7 +327,7 @@ impl RunningTask {
 
 		self.sender
 			.send(FromFetchTask::Message(AllMessages::NetworkBridge(
-				NetworkBridgeMessage::SendRequests(vec![requests], IfDisconnected::TryConnect),
+				NetworkBridgeMessage::SendRequests(vec![requests], IfDisconnected::ImmediateError),
 			)))
 			.await
 			.map_err(|_| TaskError::ShuttingDown)?;

polkadot/node/network/availability-distribution/src/requester/fetch_task/tests.rs

@@ -230,7 +230,7 @@ impl TestRun {
 		match msg {
 			AllMessages::NetworkBridge(NetworkBridgeMessage::SendRequests(
 				reqs,
-				IfDisconnected::TryConnect,
+				IfDisconnected::ImmediateError,
 			)) => {
 				let mut valid_responses = 0;
 				for req in reqs {

polkadot/node/network/availability-distribution/src/tests/state.rs

@@ -216,7 +216,7 @@ impl TestState {
 			match msg {
 				AllMessages::NetworkBridge(NetworkBridgeMessage::SendRequests(
 					reqs,
-					IfDisconnected::TryConnect,
+					IfDisconnected::ImmediateError,
 				)) => {
 					for req in reqs {
 						// Forward requests: