From decd29adfb280d0a892155633df74bacc980d3b0 Mon Sep 17 00:00:00 2001
From: pawan <pawandhananjay@gmail.com>
Date: Sun, 1 Mar 2020 02:06:38 +0530
Subject: [PATCH] Port beacon_chain to stable futures

---
 beacon_node/beacon_chain/Cargo.toml        | 2 +-
 beacon_node/beacon_chain/src/eth1_chain.rs | 8 ++------
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/beacon_node/beacon_chain/Cargo.toml b/beacon_node/beacon_chain/Cargo.toml
index f74d3f0226..1de7d458c3 100644
--- a/beacon_node/beacon_chain/Cargo.toml
+++ b/beacon_node/beacon_chain/Cargo.toml
@@ -35,7 +35,7 @@ types = { path = "../../eth2/types" }
 tokio = "0.1.22"
 eth1 = { path = "../eth1" }
 websocket_server = { path = "../websocket_server" }
-futures = "0.1.25"
+futures = "0.3"
 genesis = { path = "../genesis" }
 integer-sqrt = "0.1"
 rand = "0.7.2"
diff --git a/beacon_node/beacon_chain/src/eth1_chain.rs b/beacon_node/beacon_chain/src/eth1_chain.rs
index 663801532a..a740c514f5 100644
--- a/beacon_node/beacon_chain/src/eth1_chain.rs
+++ b/beacon_node/beacon_chain/src/eth1_chain.rs
@@ -1,7 +1,6 @@
 use crate::metrics;
 use eth1::{Config as Eth1Config, Eth1Block, Service as HttpService};
 use eth2_hashing::hash;
-use futures::Future;
 use slog::{debug, error, trace, Logger};
 use ssz::{Decode, Encode};
 use ssz_derive::{Decode, Encode};
@@ -278,11 +277,8 @@ impl<T: EthSpec, S: Store<T>> CachingEth1Backend<T, S> {
     }
 
     /// Starts the routine which connects to the external eth1 node and updates the caches.
-    pub fn start(
-        &self,
-        exit: tokio::sync::oneshot::Receiver<()>,
-    ) -> impl Future<Item = (), Error = ()> {
-        self.core.auto_update(exit)
+    pub async fn start(&self, exit: tokio::sync::oneshot::Receiver<()>) -> Result<(), ()> {
+        self.core.auto_update(exit).await
     }
 
     /// Instantiates `self` from an existing service.