From 4c7e011fea9d2083c39fd45af5c6a8f6d4b32627 Mon Sep 17 00:00:00 2001
From: Robert Habermeier <rphmeier@gmail.com>
Date: Wed, 21 Jul 2021 17:01:24 -0500
Subject: [PATCH] never mode for StagnantCheckInterval

---
 node/core/chain-selection/src/lib.rs | 36 ++++++++++++++++++----------
 node/service/src/lib.rs              |  7 ++++--
 2 files changed, 28 insertions(+), 15 deletions(-)

diff --git a/node/core/chain-selection/src/lib.rs b/node/core/chain-selection/src/lib.rs
index 9862f60d7de8..91e766f53df2 100644
--- a/node/core/chain-selection/src/lib.rs
+++ b/node/core/chain-selection/src/lib.rs
@@ -28,6 +28,7 @@ use polkadot_node_subsystem::{
 use kvdb::KeyValueDB;
 use parity_scale_codec::Error as CodecError;
 use futures::channel::oneshot;
+use futures::future::Either;
 use futures::prelude::*;
 
 use std::time::{UNIX_EPOCH, Duration,SystemTime};
@@ -244,7 +245,7 @@ impl Clock for SystemClock {
 
 /// The interval, in seconds to check for stagnant blocks.
 #[derive(Debug, Clone)]
-pub struct StagnantCheckInterval(Duration);
+pub struct StagnantCheckInterval(Option<Duration>);
 
 impl Default for StagnantCheckInterval {
 	fn default() -> Self {
@@ -255,28 +256,37 @@ impl Default for StagnantCheckInterval {
 		// between 2 validators is D + 5s.
 		const DEFAULT_STAGNANT_CHECK_INTERVAL: Duration = Duration::from_secs(5);
 
-		StagnantCheckInterval(DEFAULT_STAGNANT_CHECK_INTERVAL)
+		StagnantCheckInterval(Some(DEFAULT_STAGNANT_CHECK_INTERVAL))
 	}
 }
 
 impl StagnantCheckInterval {
 	/// Create a new stagnant-check interval wrapping the given duration.
 	pub fn new(interval: Duration) -> Self {
-		StagnantCheckInterval(interval)
+		StagnantCheckInterval(Some(interval))
 	}
 
-	fn timeout_stream(&self) -> impl Stream<Item = ()> {
-		let interval = self.0;
-		let mut delay = futures_timer::Delay::new(interval);
+	/// Create a `StagnantCheckInterval` which never triggers.
+	pub fn never() -> Self {
+		StagnantCheckInterval(None)
+	}
 
-		futures::stream::poll_fn(move |cx| {
-			let poll = delay.poll_unpin(cx);
-			if poll.is_ready() {
-				delay.reset(interval)
-			}
+	fn timeout_stream(&self) -> impl Stream<Item = ()> {
+		match self.0 {
+			Some(interval) => Either::Left({
+				let mut delay = futures_timer::Delay::new(interval);
+
+				futures::stream::poll_fn(move |cx| {
+					let poll = delay.poll_unpin(cx);
+					if poll.is_ready() {
+						delay.reset(interval)
+					}
 
-			poll.map(Some)
-		})
+					poll.map(Some)
+				})
+			}),
+			None => Either::Right(futures::stream::pending()),
+		}
 	}
 }
 
diff --git a/node/service/src/lib.rs b/node/service/src/lib.rs
index 5c92d00ca7d7..4ab09e6cb239 100644
--- a/node/service/src/lib.rs
+++ b/node/service/src/lib.rs
@@ -42,7 +42,10 @@ use {
 	polkadot_node_core_av_store::Error as AvailabilityError,
 	polkadot_node_core_approval_voting::Config as ApprovalVotingConfig,
 	polkadot_node_core_candidate_validation::Config as CandidateValidationConfig,
-	polkadot_node_core_chain_selection::Config as ChainSelectionConfig,
+	polkadot_node_core_chain_selection::{
+		self as chain_selection_subsystem,
+		Config as ChainSelectionConfig,
+	},
 	polkadot_node_core_dispute_coordinator::Config as DisputeCoordinatorConfig,
 	polkadot_overseer::BlockInfo,
 	sp_trie::PrefixedMemoryDB,
@@ -663,7 +666,7 @@ pub fn new_full<RuntimeApi, Executor, OverseerGenerator>(
 
 	let chain_selection_config = ChainSelectionConfig {
 		col_data: crate::parachains_db::REAL_COLUMNS.col_chain_selection_data,
-		stagnant_check_interval: Default::default(),
+		stagnant_check_interval: chain_selection_subsystem::StagnantCheckInterval::never(),
 	};
 
 	let dispute_coordinator_config = DisputeCoordinatorConfig {