Initial GRANDPA integration (#866)

* implement grandpa client

* consensus gossip with arbitrary topics

* defer GRANDPA messages until referenced blocks imported

* set up communication for voter in a transparent way

* instantiate GRANDPA voter

* keep last round state on disk

* switch back to crates.io finality-grandpa

* update cargo.lock

* use new `collect_garbage` API

* update sync test framework and make public

* test that observers can observe

* fix warning

* use more idiomatic predicate for collecting garbage in gossip

* kill spaces

* fix date

substrate/Cargo.lock

@@ -42,7 +42,7 @@ name = "aio-limited"
 version = "0.1.0"
 source = "git+https://github.com/paritytech/aio-limited.git#1f42497dcd2a6f85b83af97cd80314b26a1e4a9e"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "quick-error 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -467,7 +467,7 @@ source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9
 dependencies = [
  "base64 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "chashmap 2.2.1 (git+https://github.com/redox-os/tfs)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "tempfile 3.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -563,7 +563,7 @@ name = "exit-future"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -600,6 +600,18 @@ dependencies = [
  "libc 0.2.43 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "finality-grandpa"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 2.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec-derive 2.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parking_lot 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "fixed-hash"
 version = "0.2.2"
@@ -654,7 +666,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "futures"
-version = "0.1.21"
+version = "0.1.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -662,7 +674,7 @@ name = "futures-cpupool"
 version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -787,7 +799,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "base64 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures-cpupool 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "httparse 1.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "iovec 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -869,7 +881,7 @@ name = "jsonrpc-core"
 version = "8.0.2"
 source = "git+https://github.com/paritytech/jsonrpc.git#53f814e94317313ccb485eb57e435c921a974cf0"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1031,7 +1043,7 @@ version = "0.1.0"
 source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d#8111062f0177fd7423626f2db9560273644a4c4d"
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "libp2p-dns 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "libp2p-floodsub 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
@@ -1063,7 +1075,7 @@ dependencies = [
  "bs58 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "multiaddr 0.3.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "multihash 0.8.1-pre (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
@@ -1083,7 +1095,7 @@ name = "libp2p-dns"
 version = "0.1.0"
 source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d#8111062f0177fd7423626f2db9560273644a4c4d"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "multiaddr 0.3.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
@@ -1100,7 +1112,7 @@ dependencies = [
  "byteorder 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "multiaddr 0.3.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
@@ -1119,7 +1131,7 @@ source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "libp2p-peerstore 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1142,7 +1154,7 @@ dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "datastore 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "libp2p-identify 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "libp2p-ping 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
@@ -1165,7 +1177,7 @@ source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1181,7 +1193,7 @@ source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9
 dependencies = [
  "bs58 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "datastore 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "multiaddr 0.3.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "owning_ref 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1195,7 +1207,7 @@ version = "0.1.0"
 source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d#8111062f0177fd7423626f2db9560273644a4c4d"
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "multiaddr 0.3.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
@@ -1212,7 +1224,7 @@ version = "0.1.1"
 source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d#8111062f0177fd7423626f2db9560273644a4c4d"
 dependencies = [
  "aio-limited 0.1.0 (git+https://github.com/paritytech/aio-limited.git)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-executor 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1225,7 +1237,7 @@ version = "0.1.0"
 source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d#8111062f0177fd7423626f2db9560273644a4c4d"
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "libp2p-peerstore 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1247,7 +1259,7 @@ dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "ctr 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "eth-secp256k1 0.5.7 (git+https://github.com/paritytech/rust-secp256k1)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "protobuf 2.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1264,7 +1276,7 @@ name = "libp2p-tcp-transport"
 version = "0.1.0"
 source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d#8111062f0177fd7423626f2db9560273644a4c4d"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "multiaddr 0.3.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
@@ -1278,7 +1290,7 @@ name = "libp2p-transport-timeout"
 version = "0.1.0"
 source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d#8111062f0177fd7423626f2db9560273644a4c4d"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-timer 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1289,7 +1301,7 @@ name = "libp2p-uds"
 version = "0.1.0"
 source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d#8111062f0177fd7423626f2db9560273644a4c4d"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "multiaddr 0.3.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
@@ -1301,7 +1313,7 @@ name = "libp2p-websocket"
 version = "0.1.0"
 source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d#8111062f0177fd7423626f2db9560273644a4c4d"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "multiaddr 0.3.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
@@ -1317,7 +1329,7 @@ version = "0.1.0"
 source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d#8111062f0177fd7423626f2db9560273644a4c4d"
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p-core 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1509,7 +1521,7 @@ version = "0.1.0"
 source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d#8111062f0177fd7423626f2db9560273644a4c4d"
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1582,7 +1594,7 @@ version = "0.1.0"
 dependencies = [
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "exit-future 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "node-primitives 0.1.0",
  "node-runtime 0.1.0",
@@ -1631,7 +1643,7 @@ dependencies = [
 name = "node-network"
 version = "0.1.0"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "node-consensus 0.1.0",
  "node-primitives 0.1.0",
@@ -2169,7 +2181,7 @@ name = "relay"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2186,7 +2198,7 @@ version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2248,7 +2260,7 @@ version = "0.1.0"
 source = "git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d#8111062f0177fd7423626f2db9560273644a4c4d"
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2807,7 +2819,7 @@ version = "0.1.0"
 dependencies = [
  "ctrlc 3.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "node-cli 0.1.0",
  "vergen 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2817,7 +2829,7 @@ name = "substrate-bft"
 version = "0.1.0"
 dependencies = [
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-codec 2.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2843,7 +2855,7 @@ dependencies = [
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "exit-future 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "fdlimit 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "names 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2867,7 +2879,7 @@ version = "0.1.0"
 dependencies = [
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "hash-db 0.9.0 (git+https://github.com/paritytech/trie)",
  "heapsize 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2935,6 +2947,23 @@ dependencies = [
  "wasmi 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "substrate-finality-grandpa"
+version = "0.1.0"
+dependencies = [
+ "finality-grandpa 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 2.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parking_lot 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-primitives 0.1.0",
+ "substrate-client 0.1.0",
+ "substrate-keyring 0.1.0",
+ "substrate-network 0.1.0",
+ "substrate-primitives 0.1.0",
+ "tokio 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "substrate-keyring"
 version = "0.1.0"
@@ -2990,7 +3019,7 @@ dependencies = [
  "bitflags 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "linked-hash-map 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-codec 2.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3014,7 +3043,7 @@ dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.43 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p 0.1.0 (git+https://github.com/tomaka/libp2p-rs?rev=8111062f0177fd7423626f2db9560273644a4c4d)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3108,7 +3137,7 @@ version = "0.3.0"
 dependencies = [
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "exit-future 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-codec 2.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3139,7 +3168,7 @@ version = "0.3.0"
 dependencies = [
  "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "fdlimit 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 0.1.0",
  "substrate-client 0.1.0",
@@ -3240,7 +3269,7 @@ name = "substrate-transaction-pool"
 version = "0.1.0"
 dependencies = [
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-codec 2.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3424,7 +3453,7 @@ name = "tk-listen"
 version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3435,7 +3464,7 @@ name = "tokio"
 version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-executor 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-fs 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3453,7 +3482,7 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -3463,7 +3492,7 @@ version = "0.1.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "iovec 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.14 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3480,7 +3509,7 @@ name = "tokio-current-thread"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-executor 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -3489,7 +3518,7 @@ name = "tokio-dns-unofficial"
 version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures-cpupool 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3500,7 +3529,7 @@ name = "tokio-executor"
 version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -3508,7 +3537,7 @@ name = "tokio-fs"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-threadpool 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -3519,7 +3548,7 @@ version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -3528,7 +3557,7 @@ name = "tokio-proto"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "net2 0.2.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3545,7 +3574,7 @@ name = "tokio-reactor"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "slab 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3558,7 +3587,7 @@ name = "tokio-service"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -3567,7 +3596,7 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "iovec 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3580,7 +3609,7 @@ version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "crossbeam-deque 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3593,7 +3622,7 @@ version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "crossbeam-utils 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "slab 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-executor 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -3603,7 +3632,7 @@ name = "tokio-tls"
 version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "native-tls 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-core 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3615,7 +3644,7 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3628,7 +3657,7 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "iovec 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.43 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3894,7 +3923,7 @@ name = "want"
 version = "0.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "try-lock 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -3919,7 +3948,7 @@ dependencies = [
  "bitflags 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "hyper 0.10.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "native-tls 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4036,7 +4065,7 @@ version = "0.1.0"
 source = "git+https://github.com/paritytech/yamux#5acf79ecfb69ccdcb65c9f624f285b79716a029d"
 dependencies = [
  "bytes 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "nohash-hasher 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4119,6 +4148,7 @@ dependencies = [
 "checksum failure_derive 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "946d0e98a50d9831f5d589038d2ca7f8f455b1c21028c0db0e84116a12696426"
 "checksum fake-simd 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e88a8acf291dafb59c2d96e8f59828f3838bb1a70398823ade51a84de6a6deed"
 "checksum fdlimit 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b1ee15a7050e5580b3712877157068ea713b245b080ff302ae2ca973cfcd9baa"
+"checksum finality-grandpa 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "7c9a8a25e71e4a11a1a5ef36a9ad09b4ae8c4e0bcf27a900137899ac678b01b0"
 "checksum fixed-hash 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "0d5ec8112f00ea8a483e04748a85522184418fd1cf02890b626d8fc28683f7de"
 "checksum fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)" = "2fad85553e09a6f881f739c29f0b00b0f01357c743266d478b68951ce23285f3"
 "checksum foreign-types 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f6f339eb8adc052cd2ca78910fda869aefa38d22d5cb648e6485e4d3fc06f3b1"
@@ -4126,7 +4156,7 @@ dependencies = [
 "checksum fs-swap 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "31a94e9407e53addc49de767234a0b000978523c59117e5badb575ccbb8370f6"
 "checksum fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2e9763c69ebaae630ba35f74888db465e49e259ba1bc0eda7d06f4a067615d82"
 "checksum fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
-"checksum futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)" = "1a70b146671de62ec8c8ed572219ca5d594d9b06c0b364d5e67b722fc559b48c"
+"checksum futures 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)" = "0c84b40c7e2de99ffd70602db314a7a8c26b2b3d830e6f7f7a142a8860ab3ca4"
 "checksum futures-cpupool 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "ab90cde24b3319636588d0c35fe03b1333857621051837ed769faefb4c2162e4"
 "checksum gcc 0.3.54 (registry+https://github.com/rust-lang/crates.io-index)" = "5e33ec290da0d127825013597dbdfc28bee4964690c7ce1166cbc2a7bd08b1bb"
 "checksum generic-array 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ef25c5683767570c2bbd7deba372926a55eaae9982d7726ee2a1050239d45b9d"

substrate/Cargo.toml

@@ -24,6 +24,7 @@ members = [
 	"core/client",
 	"core/client/db",
 	"core/executor",
+	"core/finality-grandpa",
 	"core/keyring",
 	"core/misbehavior-check",
 	"core/network",

substrate/core/finality-grandpa/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "substrate-finality-grandpa"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+
+[dependencies]
+futures = "0.1.17"
+parity-codec = "2.0"
+sr-primitives = { path = "../sr-primitives" }
+substrate-primitives = { path = "../primitives" }
+substrate-client = { path = "../client" }
+log = "0.4"
+tokio = "0.1.7"
+
+[dependencies.finality-grandpa]
+version = "0.1.3"
+features = ["derive-codec"]
+
+[dev-dependencies]
+substrate-network = { path = "../network", features = ["test-helpers"] }
+parking_lot = "0.4"
+substrate-keyring = { path = "../keyring" }

substrate/core/finality-grandpa/src/lib.rs

@@ -0,0 +1,767 @@
+// Copyright 2018 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Integration of the GRANDPA finality gadget into substrate.
+//!
+//! This is a long-running future that produces finality notifications.
+
+extern crate finality_grandpa as grandpa;
+extern crate futures;
+extern crate substrate_client as client;
+extern crate sr_primitives as runtime_primitives;
+extern crate substrate_primitives;
+extern crate tokio;
+extern crate parity_codec as codec;
+
+#[macro_use]
+extern crate log;
+
+#[cfg(test)]
+extern crate substrate_network as network;
+
+#[cfg(test)]
+extern crate parking_lot;
+
+#[cfg(test)]
+extern crate substrate_keyring as keyring;
+
+use futures::prelude::*;
+use futures::stream::Fuse;
+use futures::sync::mpsc;
+use client::{Client, ImportNotifications, backend::Backend, CallExecutor};
+use codec::{Encode, Decode};
+use runtime_primitives::traits::{As, NumberFor, Block as BlockT, Header as HeaderT};
+use runtime_primitives::generic::BlockId;
+use substrate_primitives::{ed25519, AuthorityId, Blake2Hasher};
+use tokio::timer::Interval;
+
+use grandpa::Error as GrandpaError;
+use grandpa::{voter, round::State as RoundState, Prevote, Precommit, Equivocation};
+
+use std::collections::{VecDeque, HashMap};
+use std::sync::Arc;
+use std::time::{Instant, Duration};
+
+const LAST_COMPLETED_KEY: &[u8] = b"grandpa_completed_round";
+
+/// A GRANDPA message for a substrate chain.
+pub type Message<Block> = grandpa::Message<<Block as BlockT>::Hash>;
+/// A signed message.
+pub type SignedMessage<Block> = grandpa::SignedMessage<<Block as BlockT>::Hash, ed25519::Signature, AuthorityId>;
+
+/// Configuration for the GRANDPA service.
+pub struct Config {
+	/// The expected duration for a message to be gossiped across the network.
+	pub gossip_duration: Duration,
+	/// The voters.
+	// TODO: make dynamic
+	pub voters: Vec<AuthorityId>,
+	/// The local signing key.
+	pub local_key: Option<Arc<ed25519::Pair>>,
+}
+
+/// Errors that can occur while voting in GRANDPA.
+#[derive(Debug)]
+pub enum Error {
+	/// An error within grandpa.
+	Grandpa(GrandpaError),
+	/// A network error.
+	Network(String),
+	/// A blockchain error.
+	Blockchain(String),
+	/// A timer failed to fire.
+	Timer(::tokio::timer::Error),
+}
+
+impl From<GrandpaError> for Error {
+	fn from(e: GrandpaError) -> Self {
+		Error::Grandpa(e)
+	}
+}
+
+/// A handle to the network. This is generally implemented by providing some
+/// handle to a gossip service or similar.
+///
+/// Intended to be a lightweight handle such as an `Arc`.
+pub trait Network: Clone {
+	/// A stream of input messages for a topic.
+	type In: Stream<Item=Vec<u8>,Error=()>;
+
+	/// Get a stream of messages for a specific round. This stream should
+	/// never logically conclude.
+	fn messages_for(&self, round: u64) -> Self::In;
+
+	/// Send a message at a specific round out.
+	fn send_message(&self, round: u64, message: Vec<u8>);
+
+	/// Clean up messages for a round.
+	fn drop_messages(&self, round: u64);
+}
+
+/// Something which can determine if a block is known.
+pub trait BlockStatus<Block: BlockT> {
+	/// Return `Ok(Some(number))` or `Ok(None)` depending on whether the block
+	/// is definitely known and has been imported.
+	/// If an unexpected error occurs, return that.
+	fn block_number(&self, hash: Block::Hash) -> Result<Option<u32>, Error>;
+}
+
+impl<B, E, Block: BlockT> BlockStatus<Block> for Arc<Client<B, E, Block>> where
+	B: Backend<Block, Blake2Hasher>,
+	E: CallExecutor<Block, Blake2Hasher>,
+	NumberFor<Block>: As<u32>,
+{
+	fn block_number(&self, hash: Block::Hash) -> Result<Option<u32>, Error> {
+		self.block_number_from_id(&BlockId::Hash(hash))
+			.map_err(|e| Error::Blockchain(format!("{:?}", e)))
+			.map(|num| num.map(|n| n.as_()))
+	}
+}
+
+/// Buffering imported messages until blocks with given hashes are imported.
+pub struct UntilImported<Block: BlockT, Status, I> {
+	import_notifications: Fuse<ImportNotifications<Block>>,
+	status_check: Status,
+	inner: Fuse<I>,
+	ready: VecDeque<SignedMessage<Block>>,
+	check_pending: Interval,
+	pending: HashMap<Block::Hash, Vec<SignedMessage<Block>>>,
+}
+
+impl<Block: BlockT, Status: BlockStatus<Block>, I: Stream> UntilImported<Block, Status, I> {
+	fn new(
+		import_notifications: ImportNotifications<Block>,
+		status_check: Status,
+		stream: I,
+	) -> Self {
+		// how often to check if pending messages that are waiting for blocks to be
+		// imported can be checked.
+		//
+		// the import notifications interval takes care of most of this; this is
+		// used in the event of missed import notifications
+		const CHECK_PENDING_INTERVAL: Duration = Duration::from_secs(5);
+		let now = Instant::now();
+
+		let check_pending = Interval::new(now + CHECK_PENDING_INTERVAL, CHECK_PENDING_INTERVAL);
+		UntilImported {
+			import_notifications: import_notifications.fuse(),
+			status_check,
+			inner: stream.fuse(),
+			ready: VecDeque::new(),
+			check_pending,
+			pending: HashMap::new(),
+		}
+	}
+}
+
+impl<Block: BlockT, Status: BlockStatus<Block>, I> Stream for UntilImported<Block, Status, I>
+	where I: Stream<Item=SignedMessage<Block>,Error=Error>
+{
+	type Item = SignedMessage<Block>;
+	type Error = Error;
+
+	fn poll(&mut self) -> Poll<Option<SignedMessage<Block>>, Error> {
+		loop {
+			match self.inner.poll() {
+				Err(e) => return Err(e),
+				Ok(Async::Ready(None)) => return Ok(Async::Ready(None)),
+				Ok(Async::Ready(Some(signed_message))) => {
+					let (&target_hash, target_number) = signed_message.target();
+
+					// new message: hold it until the block is known.
+					if let Some(number) = self.status_check.block_number(target_hash)? {
+						if number != target_number {
+							warn!(
+								target: "afg",
+								"Authority {:?} signed GRANDPA message with \
+								wrong block number for hash {}",
+								signed_message.id,
+								target_hash
+							);
+						} else {
+							self.ready.push_back(signed_message)
+						}
+					} else {
+						self.pending.entry(target_hash)
+							.or_insert_with(Vec::new)
+							.push(signed_message);
+					}
+				}
+				Ok(Async::NotReady) => break,
+			}
+		}
+
+		loop {
+			match self.import_notifications.poll() {
+				Err(_) => return Err(Error::Network(format!("Failed to get new message"))),
+				Ok(Async::Ready(None)) => return Ok(Async::Ready(None)),
+				Ok(Async::Ready(Some(notification))) => {
+					// new block imported. queue up all messages tied to that hash.
+					if let Some(messages) = self.pending.remove(&notification.hash) {
+						self.ready.extend(messages);
+				 	}
+				}
+				Ok(Async::NotReady) => break,
+			}
+		}
+
+		let mut update_interval = false;
+		while let Async::Ready(Some(_)) = self.check_pending.poll().map_err(Error::Timer)? {
+			update_interval = true;
+		}
+
+		if update_interval {
+			let mut known_keys = Vec::new();
+			for &block_hash in self.pending.keys() {
+				if let Some(number) = self.status_check.block_number(block_hash)? {
+					known_keys.push((block_hash, number));
+				}
+			}
+
+			for (known_hash, canon_number) in known_keys {
+				if let Some(mut pending_messages) = self.pending.remove(&known_hash) {
+					// verify canonicality of pending messages.
+					pending_messages.retain(|msg| {
+						let number_correct = msg.target().1 == canon_number;
+						if !number_correct {
+							warn!(
+								target: "afg",
+								"Authority {:?} signed GRANDPA message with \
+								wrong block number for hash {}",
+								msg.id,
+								known_hash,
+							);
+						}
+						number_correct
+					});
+					self.ready.extend(pending_messages);
+				}
+			}
+		}
+
+		if let Some(ready) = self.ready.pop_front() {
+			return Ok(Async::Ready(Some(ready)))
+		}
+
+		if self.import_notifications.is_done() && self.inner.is_done() {
+			Ok(Async::Ready(None))
+		} else {
+			Ok(Async::NotReady)
+		}
+	}
+}
+
+// clears the network messages for inner round on drop.
+struct ClearOnDrop<I, N: Network> {
+	round: u64,
+	inner: I,
+	network: N,
+}
+
+impl<I: Sink, N: Network> Sink for ClearOnDrop<I, N> {
+	type SinkItem = I::SinkItem;
+	type SinkError = I::SinkError;
+
+	fn start_send(&mut self, item: Self::SinkItem) -> StartSend<Self::SinkItem, Self::SinkError> {
+		self.inner.start_send(item)
+	}
+
+	fn poll_complete(&mut self) -> Poll<(), Self::SinkError> {
+		self.inner.poll_complete()
+	}
+
+	fn close(&mut self) -> Poll<(), Self::SinkError> {
+		self.inner.close()
+	}
+}
+
+impl<I, N: Network> Drop for ClearOnDrop<I, N> {
+	fn drop(&mut self) {
+		self.network.drop_messages(self.round);
+	}
+}
+
+// converts a message stream into a stream of signed messages.
+// the output stream checks signatures also.
+fn checked_message_stream<Block: BlockT, S>(inner: S, voters: Vec<AuthorityId>)
+	-> impl Stream<Item=SignedMessage<Block>,Error=Error> where
+	S: Stream<Item=Vec<u8>,Error=()>
+{
+	inner
+		.filter_map(|raw| {
+			let decoded = SignedMessage::<Block>::decode(&mut &raw[..]);
+			if decoded.is_none() {
+				debug!(target: "afg", "Skipping malformed message {:?}", raw);
+			}
+			decoded
+		})
+		.and_then(move |msg| {
+			// check signature.
+			if !voters.contains(&msg.id) {
+				debug!(target: "afg", "Skipping message from unknown voter {}", msg.id);
+				return Ok(None);
+			}
+
+			let as_public = ::ed25519::Public::from_raw(msg.id.0);
+			let encoded_raw = msg.message.encode();
+			if ::ed25519::verify_strong(&msg.signature, &encoded_raw, as_public) {
+				Ok(Some(msg))
+			} else {
+				debug!(target: "afg", "Skipping message with bad signature");
+				Ok(None)
+			}
+		})
+		.filter_map(|x| x)
+		.map_err(|()| Error::Network(format!("Failed to receive message on unbounded stream")))
+}
+
+fn outgoing_messages<Block: BlockT, N: Network>(
+	local_key: Option<Arc<ed25519::Pair>>,
+	voters: Vec<AuthorityId>,
+	round: u64,
+	network: N,
+) -> (
+	impl Stream<Item=SignedMessage<Block>,Error=Error>,
+	impl Sink<SinkItem=Message<Block>,SinkError=Error>,
+) {
+	let locals = local_key.and_then(|pair| {
+		let public = pair.public();
+		voters.iter().find(|id| id.0 == public.0).map(move |id| (pair, id.clone()))
+	});
+
+	let (tx, rx) = mpsc::unbounded();
+	let rx = rx
+		.map(move |msg: Message<Block>| {
+			// when locals exist. sign messages on import
+			if let Some((ref pair, local_id)) = locals {
+				let encoded = msg.encode();
+				let signature = pair.sign(&encoded[..]);
+				let signed = SignedMessage::<Block> {
+					message: msg,
+					signature,
+					id: local_id,
+				};
+
+				// forward to network.
+				network.send_message(round, signed.encode());
+				Some(signed)
+			} else {
+				None
+			}
+		})
+		.filter_map(|x| x)
+		.map_err(move |()| Error::Network(
+			format!("Failed to receive on unbounded receiver for round {}", round)
+		));
+
+	let tx = tx.sink_map_err(move |e| Error::Network(format!("Failed to broadcast message \
+		to network in round {}: {:?}", round, e)));
+
+	(rx, tx)
+}
+
+/// The environment we run GRANDPA in.
+pub struct Environment<B, E, Block: BlockT, N: Network> {
+	inner: Arc<Client<B, E, Block>>,
+	voters: HashMap<AuthorityId, usize>,
+	config: Config,
+	network: N,
+}
+
+impl<Block: BlockT, B, E, N> grandpa::Chain<Block::Hash> for Environment<B, E, Block, N> where
+	Block: 'static,
+	B: Backend<Block, Blake2Hasher> + 'static,
+	E: CallExecutor<Block, Blake2Hasher> + 'static,
+	N: Network + 'static,
+	N::In: 'static,
+	NumberFor<Block>: As<u32>,
+{
+	fn ancestry(&self, base: Block::Hash, block: Block::Hash) -> Result<Vec<Block::Hash>, GrandpaError> {
+		let tree_route_res = ::client::blockchain::tree_route(
+			self.inner.backend().blockchain(),
+			BlockId::Hash(block),
+			BlockId::Hash(base),
+		);
+
+		let tree_route = match tree_route_res {
+			Ok(tree_route) => tree_route,
+			Err(e) => {
+				debug!(target: "afg", "Encountered error computing ancestry between block {:?} and base {:?}: {:?}",
+					block, base, e);
+
+				return Err(GrandpaError::NotDescendent);
+			}
+		};
+
+		if tree_route.common_block().hash != base {
+			return Err(GrandpaError::NotDescendent);
+		}
+
+		// skip one because our ancestry is meant to start from the parent of `block`,
+		// and `tree_route` includes it.
+		Ok(tree_route.retracted().iter().skip(1).map(|e| e.hash).collect())
+	}
+
+	fn best_chain_containing(&self, block: Block::Hash) -> Option<(Block::Hash, u32)> {
+		match self.inner.best_containing(block, None) {
+			Ok(Some(hash)) => {
+				let header = self.inner.header(&BlockId::Hash(hash)).ok()?
+					.expect("Header known to exist after `best_containing` call; qed");
+
+				Some((hash, header.number().as_()))
+			}
+			Ok(None) => None,
+			Err(e) => {
+				debug!(target: "afg", "Encountered error finding best chain containing {:?}: {:?}", block, e);
+				None
+			}
+		}
+	}
+}
+
+impl<B, E, Block: BlockT, N> voter::Environment<Block::Hash> for Environment<B, E, Block, N> where
+	Block: 'static,
+	B: Backend<Block, Blake2Hasher> + 'static,
+	E: CallExecutor<Block, Blake2Hasher> + 'static,
+	N: Network + 'static,
+	N::In: 'static,
+	NumberFor<Block>: As<u32>,
+{
+	type Timer = Box<Future<Item = (), Error = Self::Error>>;
+	type Id = AuthorityId;
+	type Signature = ed25519::Signature;
+	type In = Box<Stream<Item = ::grandpa::SignedMessage<Block::Hash, Self::Signature, Self::Id>, Error = Self::Error>>;
+	type Out = Box<Sink<SinkItem = ::grandpa::Message<Block::Hash>, SinkError = Self::Error>>;
+	type Error = Error;
+
+	fn round_data(
+		&self,
+		round: u64
+	) -> voter::RoundData<Self::Timer, Self::Id, Self::In, Self::Out> {
+		use client::BlockchainEvents;
+		use tokio::timer::Delay;
+
+		let now = Instant::now();
+		let prevote_timer = Delay::new(now + self.config.gossip_duration * 2);
+		let precommit_timer = Delay::new(now + self.config.gossip_duration * 4);
+
+		// TODO: dispatch this with `mpsc::spawn`.
+		let incoming = checked_message_stream::<Block, _>(
+			self.network.messages_for(round),
+			self.config.voters.clone(),
+		);
+
+		let (out_rx, outgoing) = outgoing_messages::<Block, _>(
+			self.config.local_key.clone(),
+			self.config.voters.clone(),
+			round,
+			self.network.clone(),
+		);
+
+		// schedule incoming messages from the network to be held until
+		// corresponding blocks are imported.
+		let incoming = UntilImported::new(
+			self.inner.import_notification_stream(),
+			self.inner.clone(),
+			incoming,
+		);
+
+		// join incoming network messages with locally originating ones.
+		let incoming = Box::new(incoming.select(out_rx));
+
+		// schedule network message cleanup when sink drops.
+		let outgoing = Box::new(ClearOnDrop {
+			round,
+			network: self.network.clone(),
+			inner: outgoing,
+		});
+
+		voter::RoundData {
+			prevote_timer: Box::new(prevote_timer.map_err(Error::Timer)),
+			precommit_timer: Box::new(precommit_timer.map_err(Error::Timer)),
+			voters: self.voters.clone(),
+			incoming,
+			outgoing,
+		}
+	}
+
+	fn completed(&self, round: u64, state: RoundState<Block::Hash>) {
+		let encoded_state = (round, state).encode();
+		if let Err(e) = self.inner.backend()
+			.insert_aux(&[(LAST_COMPLETED_KEY, &encoded_state[..])], &[])
+		{
+			warn!(target: "afg", "Error bookkeeping last completed round in DB: {:?}", e);
+		}
+	}
+
+	fn finalize_block(&self, hash: Block::Hash, number: u32) {
+		// TODO: don't unconditionally notify.
+		if let Err(e) = self.inner.finalize_block(BlockId::Hash(hash), true) {
+			warn!(target: "afg", "Error applying finality to block {:?}: {:?}", (hash, number), e);
+		}
+	}
+
+	fn prevote_equivocation(
+		&self,
+		_round: u64,
+		equivocation: ::grandpa::Equivocation<Self::Id, Prevote<Block::Hash>, Self::Signature>
+	) {
+		warn!(target: "afg", "Detected prevote equivocation in the finality worker: {:?}", equivocation);
+		// nothing yet; this could craft misbehavior reports of some kind.
+	}
+
+	fn precommit_equivocation(
+		&self,
+		_round: u64,
+		equivocation: Equivocation<Self::Id, Precommit<Block::Hash>, Self::Signature>
+	) {
+		warn!(target: "afg", "Detected precommit equivocation in the finality worker: {:?}", equivocation);
+		// nothing yet
+	}
+}
+
+/// Run a GRANDPA voter as a task. The returned future should be executed in a tokio runtime.
+pub fn run_voter<B, E, Block: BlockT, N>(
+	config: Config,
+	client: Arc<Client<B, E, Block>>,
+	voters: HashMap<AuthorityId, usize>,
+	network: N,
+) -> Result<impl Future<Item=(),Error=()>,client::error::Error> where
+	Block::Hash: Ord,
+	B: Backend<Block, Blake2Hasher> + 'static,
+	E: CallExecutor<Block, Blake2Hasher> + 'static,
+	N: Network + 'static,
+	N::In: 'static,
+	NumberFor<Block>: As<u32>,
+{
+	let chain_info = client.info()?;
+	let genesis_hash = chain_info.chain.genesis_hash;
+	let last_finalized = (
+		chain_info.chain.finalized_hash,
+		chain_info.chain.finalized_number.as_()
+	);
+
+	let (last_round_number, last_state) = match client.backend().get_aux(LAST_COMPLETED_KEY)? {
+		None => (0, RoundState::genesis((genesis_hash, 0))),
+		Some(raw) => <(u64, RoundState<Block::Hash>)>::decode(&mut &raw[..])
+			.ok_or_else(|| ::client::error::ErrorKind::Backend(
+				format!("Last GRANDPA round state kept in invalid format")
+			))?
+	};
+
+	let environment = Arc::new(Environment {
+		inner: client,
+		config,
+		voters,
+		network,
+	});
+
+	let voter = voter::Voter::new(
+		environment,
+		last_round_number,
+		last_state,
+		last_finalized,
+	);
+
+	Ok(voter.map_err(|e| warn!("GRANDPA Voter failed: {:?}", e)))
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use network::test::*;
+	use parking_lot::Mutex;
+	use tokio::runtime::current_thread;
+	use keyring::Keyring;
+	use client::BlockchainEvents;
+
+	#[derive(Clone)]
+	struct TestGrandpaNetwork {
+		inner: Arc<Mutex<TestNet>>,
+		peer_id: usize,
+	}
+
+	impl TestGrandpaNetwork {
+		fn new(inner: Arc<Mutex<TestNet>>, peer_id: usize,) -> Self {
+			TestGrandpaNetwork {
+				inner,
+				peer_id,
+			}
+		}
+	}
+
+	fn round_to_topic(round: u64) -> Hash {
+		let mut hash = Hash::default();
+		round.using_encoded(|s| {
+			let raw = hash.as_mut();
+			raw[..8].copy_from_slice(s);
+		});
+		hash
+	}
+
+	impl Network for TestGrandpaNetwork {
+		type In = Box<Stream<Item=Vec<u8>,Error=()>>;
+
+		fn messages_for(&self, round: u64) -> Self::In {
+			use network::consensus_gossip::ConsensusMessage;
+
+			let messages = self.inner.lock().peer(self.peer_id)
+				.with_spec(|spec, _| spec.gossip.messages_for(round_to_topic(round)));
+
+			let messages = messages
+				.map_err(
+					move |_| panic!("Messages for round {} dropped too early", round)
+				)
+				.map(|msg| match msg {
+					ConsensusMessage::ChainSpecific(raw, _) => {
+						let message = GossipMessage::decode(&mut &raw[..]).unwrap();
+						message.data
+					}
+					_ => panic!("Only chain-specific messages come under this stream"),
+				});
+
+			Box::new(messages)
+		}
+
+		fn send_message(&self, round: u64, message: Vec<u8>) {
+			let mut inner = self.inner.lock();
+			inner.peer(self.peer_id).gossip_message(round_to_topic(round), message);
+			inner.route();
+		}
+
+		fn drop_messages(&self, round: u64) {
+			let topic = round_to_topic(round);
+			self.inner.lock().peer(self.peer_id)
+				.with_spec(|spec, _| spec.gossip.collect_garbage(|t| t == &topic));
+		}
+	}
+
+	const TEST_GOSSIP_DURATION: Duration = Duration::from_millis(500);
+	const TEST_ROUTING_INTERVAL: Duration = Duration::from_millis(50);
+
+	#[test]
+	fn finalize_20_unanimous_3_peers() {
+		let mut net = TestNet::new(3);
+		net.peer(0).push_blocks(20, false);
+		net.sync();
+
+		let net = Arc::new(Mutex::new(net));
+		let peers = &[
+			(0, Keyring::Alice),
+			(1, Keyring::Bob),
+			(2, Keyring::Charlie),
+		];
+
+		let voters: Vec<_> = peers.iter()
+			.map(|&(_, ref key)| AuthorityId(key.to_raw_public()))
+			.collect();
+
+		let mut finality_notifications = Vec::new();
+
+		let mut runtime = current_thread::Runtime::new().unwrap();
+		for (peer_id, key) in peers {
+			let client = net.lock().peer(*peer_id).client().clone();
+			finality_notifications.push(
+				client.finality_notification_stream()
+					.take_while(|n| Ok(n.header.number() < &20))
+					.for_each(move |_| Ok(()))
+			);
+			let voter = run_voter(
+				Config {
+					gossip_duration: TEST_GOSSIP_DURATION,
+					voters: voters.clone(),
+					local_key: Some(Arc::new(key.clone().into())),
+				},
+				client,
+				voters.iter().map(|&id| (id, 1)).collect(),
+				TestGrandpaNetwork::new(net.clone(), *peer_id),
+			).expect("all in order with client and network");
+
+			runtime.spawn(voter);
+		}
+
+		// wait for all finalized on each.
+		let wait_for = ::futures::future::join_all(finality_notifications)
+			.map(|_| ())
+			.map_err(|_| ());
+
+		let drive_to_completion = ::tokio::timer::Interval::new_interval(TEST_ROUTING_INTERVAL)
+			.for_each(move |_| { net.lock().route_until_complete(); Ok(()) })
+			.map(|_| ())
+			.map_err(|_| ());
+
+		runtime.block_on(wait_for.select(drive_to_completion).map_err(|_| ())).unwrap();
+	}
+
+	#[test]
+	fn observer_can_finalize() {
+		let mut net = TestNet::new(4);
+		net.peer(0).push_blocks(20, false);
+		net.sync();
+
+		let net = Arc::new(Mutex::new(net));
+		let peers = &[
+			(0, Keyring::Alice),
+			(1, Keyring::Bob),
+			(2, Keyring::Charlie),
+		];
+
+		let voters: HashMap<_, _> = peers.iter()
+			.map(|&(_, ref key)| (AuthorityId(key.to_raw_public()), 1))
+			.collect();
+
+		let mut finality_notifications = Vec::new();
+
+		let mut runtime = current_thread::Runtime::new().unwrap();
+		let all_peers = peers.iter()
+			.cloned()
+			.map(|(id, key)| (id, Some(Arc::new(key.into()))))
+			.chain(::std::iter::once((3, None)));
+
+		for (peer_id, local_key) in all_peers {
+			let client = net.lock().peer(peer_id).client().clone();
+			finality_notifications.push(
+				client.finality_notification_stream()
+					.take_while(|n| Ok(n.header.number() < &20))
+					.for_each(move |_| Ok(()))
+			);
+			let voter = run_voter(
+				Config {
+					gossip_duration: TEST_GOSSIP_DURATION,
+					voters: voters.keys().cloned().collect(),
+					local_key,
+				},
+				client,
+				voters.clone(),
+				TestGrandpaNetwork::new(net.clone(), peer_id),
+			).expect("all in order with client and network");
+
+			runtime.spawn(voter);
+		}
+
+		// wait for all finalized on each.
+		let wait_for = ::futures::future::join_all(finality_notifications)
+			.map(|_| ())
+			.map_err(|_| ());
+
+		let drive_to_completion = ::tokio::timer::Interval::new_interval(TEST_ROUTING_INTERVAL)
+			.for_each(move |_| { net.lock().route_until_complete(); Ok(()) })
+			.map(|_| ())
+			.map_err(|_| ());
+
+		runtime.block_on(wait_for.select(drive_to_completion).map_err(|_| ())).unwrap();
+	}
+}

substrate/core/network/Cargo.toml

@@ -23,7 +23,15 @@ parity-codec = "2.0"
 parity-codec-derive = "2.0"
 substrate-network-libp2p = { path = "../../core/network-libp2p" }
 
+env_logger = { version = "0.4", optional = true }
+substrate-keyring = { path = "../../core/keyring", optional = true }
+substrate-test-client = { path = "../../core/test-client", optional = true }
+
 [dev-dependencies]
-env_logger = "0.4"
+env_logger = { version = "0.4" }
 substrate-keyring = { path = "../../core/keyring" }
 substrate-test-client = { path = "../../core/test-client" }
+
+[features]
+default = []
+test-helpers = ["env_logger", "substrate-keyring", "substrate-test-client"]

substrate/core/network/src/consensus_gossip.rs

@@ -54,7 +54,7 @@ struct MessageEntry<B: BlockT> {
 /// Consensus network protocol handler. Manages statements and candidate requests.
 pub struct ConsensusGossip<B: BlockT> {
 	peers: HashMap<NodeIndex, PeerConsensus<B::Hash>>,
-	message_sink: Option<(mpsc::UnboundedSender<ConsensusMessage<B>>, B::Hash)>,
+	live_message_sinks: HashMap<B::Hash, mpsc::UnboundedSender<ConsensusMessage<B>>>,
 	messages: Vec<MessageEntry<B>>,
 	message_hashes: HashSet<B::Hash>,
 }
@@ -64,7 +64,7 @@ impl<B: BlockT> ConsensusGossip<B> where B::Header: HeaderT<Number=u64> {
 	pub fn new() -> Self {
 		ConsensusGossip {
 			peers: HashMap::new(),
-			message_sink: None,
+			live_message_sinks: HashMap::new(),
 			messages: Default::default(),
 			message_hashes: Default::default(),
 		}
@@ -72,7 +72,7 @@ impl<B: BlockT> ConsensusGossip<B> where B::Header: HeaderT<Number=u64> {
 
 	/// Closes all notification streams.
 	pub fn abort(&mut self) {
-		self.message_sink = None;
+		self.live_message_sinks.clear();
 	}
 
 	/// Handle new connected peer.
@@ -150,23 +150,23 @@ impl<B: BlockT> ConsensusGossip<B> where B::Header: HeaderT<Number=u64> {
 	}
 
 	/// Handles incoming chain-specific message and repropagates
-	pub fn on_chain_specific(&mut self, protocol: &mut Context<B>, who: NodeIndex, message: Vec<u8>, parent_hash: B::Hash) {
+	pub fn on_chain_specific(&mut self, protocol: &mut Context<B>, who: NodeIndex, message: Vec<u8>, topic: B::Hash) {
 		debug!(target: "gossip", "received chain-specific gossip message");
-		if let Some((hash, message)) = self.handle_incoming(protocol, who, ConsensusMessage::ChainSpecific(message, parent_hash)) {
+		if let Some((hash, message)) = self.handle_incoming(protocol, who, ConsensusMessage::ChainSpecific(message, topic)) {
 			debug!(target: "gossip", "handled incoming chain-specific message");
 			// propagate to other peers.
 			self.multicast(protocol, message, Some(hash));
 		}
 	}
 
-	/// Get a stream of messages relevant to consensus on top of a given parent hash.
+	/// Get a stream of messages relevant to consensus for the given topic.
-	pub fn messages_for(&mut self, parent_hash: B::Hash) -> mpsc::UnboundedReceiver<ConsensusMessage<B>> {
+	pub fn messages_for(&mut self, topic: B::Hash) -> mpsc::UnboundedReceiver<ConsensusMessage<B>> {
 		let (sink, stream) = mpsc::unbounded();
 
 		for entry in self.messages.iter() {
 			let message_matches = match entry.message {
-				ConsensusMessage::Bft(ref msg) => msg.parent_hash == parent_hash,
+				ConsensusMessage::Bft(ref msg) => msg.parent_hash == topic,
-				ConsensusMessage::ChainSpecific(_, ref h) => h == &parent_hash,
+				ConsensusMessage::ChainSpecific(_, ref h) => h == &topic,
 			};
 
 			if message_matches {
@@ -174,14 +174,14 @@ impl<B: BlockT> ConsensusGossip<B> where B::Header: HeaderT<Number=u64> {
 			}
 		}
 
-		self.message_sink = Some((sink, parent_hash));
+		self.live_message_sinks.insert(topic, sink);
 		stream
 	}
 
 	/// Multicast a chain-specific message to other authorities.
-	pub fn multicast_chain_specific(&mut self, protocol: &mut Context<B>, message: Vec<u8>, parent_hash: B::Hash) {
+	pub fn multicast_chain_specific(&mut self, protocol: &mut Context<B>, message: Vec<u8>, topic: B::Hash) {
 		trace!(target:"gossip", "sending chain-specific message");
-		self.multicast(protocol, ConsensusMessage::ChainSpecific(message, parent_hash), None);
+		self.multicast(protocol, ConsensusMessage::ChainSpecific(message, topic), None);
 	}
 
 	/// Multicast a BFT message to other authorities
@@ -196,20 +196,21 @@ impl<B: BlockT> ConsensusGossip<B> where B::Header: HeaderT<Number=u64> {
 		self.peers.remove(&who);
 	}
 
-	/// Prune old or no longer relevant consensus messages.
+	/// Prune old or no longer relevant consensus messages. Provide a predicate
-	/// Supply an optional block hash where consensus is known to have concluded.
+	/// for pruning, which returns `false` when the items with a given topic should be pruned.
-	pub fn collect_garbage(&mut self, best_hash: Option<&B::Hash>) {
+	pub fn collect_garbage<P: Fn(&B::Hash) -> bool>(&mut self, predicate: P) {
+		self.live_message_sinks.retain(|_, sink| !sink.is_closed());
+
 		let hashes = &mut self.message_hashes;
 		let before = self.messages.len();
 		let now = Instant::now();
 		self.messages.retain(|entry| {
-			if entry.instant + MESSAGE_LIFETIME >= now &&
+			let topic = match entry.message {
-				best_hash.map_or(true, |parent_hash|
+				ConsensusMessage::Bft(ref msg) => &msg.parent_hash,
-					match entry.message {
+				ConsensusMessage::ChainSpecific(_, ref h) => h,
-						ConsensusMessage::Bft(ref msg) => &msg.parent_hash != parent_hash,
+			};
-						ConsensusMessage::ChainSpecific(_, ref h) => h != parent_hash,
+
-					})
+			if entry.instant + MESSAGE_LIFETIME >= now && predicate(topic) {
-			{
 				true
 			} else {
 				hashes.remove(&entry.hash);
@@ -223,7 +224,7 @@ impl<B: BlockT> ConsensusGossip<B> where B::Header: HeaderT<Number=u64> {
 	}
 
 	fn handle_incoming(&mut self, protocol: &mut Context<B>, who: NodeIndex, message: ConsensusMessage<B>) -> Option<(B::Hash, ConsensusMessage<B>)> {
-		let (hash, parent, message) = match message {
+		let (hash, topic, message) = match message {
 			ConsensusMessage::Bft(msg) => {
 				let parent = msg.parent_hash;
 				let generic = GenericMessage::BftMessage(msg);
@@ -236,13 +237,13 @@ impl<B: BlockT> ConsensusGossip<B> where B::Header: HeaderT<Number=u64> {
 					}
 				)
 			}
-			ConsensusMessage::ChainSpecific(msg, parent) => {
+			ConsensusMessage::ChainSpecific(msg, topic) => {
 				let generic = GenericMessage::ChainSpecific(msg);
 				(
 					::protocol::hash_message::<B>(&generic),
-					parent,
+					topic,
 					match generic {
-						GenericMessage::ChainSpecific(msg) => ConsensusMessage::ChainSpecific(msg, parent),
+						GenericMessage::ChainSpecific(msg) => ConsensusMessage::ChainSpecific(msg, topic),
 						_ => panic!("`generic` is known to be the `ChainSpecific` variant; qed"),
 					}
 				)
@@ -254,14 +255,14 @@ impl<B: BlockT> ConsensusGossip<B> where B::Header: HeaderT<Number=u64> {
 			return None;
 		}
 
-		match (protocol.client().info(), protocol.client().header(&BlockId::Hash(parent))) {
+		match (protocol.client().info(), protocol.client().header(&BlockId::Hash(topic))) {
 			(_, Err(e)) | (Err(e), _) => {
 				debug!(target:"gossip", "Error reading blockchain: {:?}", e);
 				return None;
 			},
 			(Ok(info), Ok(Some(header))) => {
 				if header.number() < &info.chain.best_number {
-					trace!(target:"gossip", "Ignored ancient message from {}, hash={}", who, parent);
+					trace!(target:"gossip", "Ignored ancient message from {}, hash={}", who, topic);
 					return None;
 				}
 			},
@@ -269,16 +270,17 @@ impl<B: BlockT> ConsensusGossip<B> where B::Header: HeaderT<Number=u64> {
 		}
 
 		if let Some(ref mut peer) = self.peers.get_mut(&who) {
+			use std::collections::hash_map::Entry;
 			peer.known_messages.insert(hash);
-			if let Some((sink, parent_hash)) = self.message_sink.take() {
+			if let Entry::Occupied(mut entry) = self.live_message_sinks.entry(topic) {
-				if parent == parent_hash {
+				debug!(target: "gossip", "Pushing relevant consensus message to sink.");
-					debug!(target: "gossip", "Pushing relevant consensus message to sink.");
+				if let Err(e) = entry.get().unbounded_send(message.clone()) {
-					if let Err(e) = sink.unbounded_send(message.clone()) {
+					trace!(target:"gossip", "Error broadcasting message notification: {:?}", e);
-						trace!(target:"gossip", "Error broadcasting message notification: {:?}", e);
-					}
 				}
 
-				self.message_sink = Some((sink, parent_hash));
+				if entry.get().is_closed() {
+					entry.remove_entry();
+				}
 			}
 		} else {
 			trace!(target:"gossip", "Ignored statement from unregistered peer {}", who);
@@ -344,7 +346,7 @@ mod tests {
 		consensus.message_hashes.insert(m2_hash);
 
 		// nothing to collect
-		consensus.collect_garbage(None);
+		consensus.collect_garbage(|_topic| true);
 		assert_eq!(consensus.messages.len(), 2);
 		assert_eq!(consensus.message_hashes.len(), 2);
 
@@ -357,13 +359,13 @@ mod tests {
 			digest: Default::default(),
 		};
 
-		consensus.collect_garbage(Some(&H256::default()));
+		consensus.collect_garbage(|&topic| topic != Default::default());
 		assert_eq!(consensus.messages.len(), 2);
 		assert_eq!(consensus.message_hashes.len(), 2);
 
 		// header that matches one of the messages
 		header.parent_hash = prev_hash;
-		consensus.collect_garbage(Some(&prev_hash));
+		consensus.collect_garbage(|topic| topic != &prev_hash);
 		assert_eq!(consensus.messages.len(), 1);
 		assert_eq!(consensus.message_hashes.len(), 1);
 		assert!(consensus.message_hashes.contains(&m2_hash));
@@ -371,7 +373,7 @@ mod tests {
 		// make timestamp expired
 		consensus.messages.clear();
 		push_msg!(m2_hash, now - MESSAGE_LIFETIME, m2);
-		consensus.collect_garbage(None);
+		consensus.collect_garbage(|_topic| true);
 		assert!(consensus.messages.is_empty());
 		assert!(consensus.message_hashes.is_empty());
 	}

substrate/core/network/src/import_queue.rs

@@ -232,7 +232,7 @@ enum SyncLink<'a, B: 'a + BlockT, E: 'a + ExecuteInContext<B>> {
 	/// Indirect link (through service).
 	Indirect(&'a RwLock<ChainSync<B>>, &'a Client<B>, &'a E),
 	/// Direct references are given.
-	#[cfg(test)]
+	#[cfg(any(test, feature = "test-helpers"))]
 	Direct(&'a mut ChainSync<B>, &'a mut Context<B>),
 }
 
@@ -402,7 +402,7 @@ impl<'a, B: 'static + BlockT, E: 'a + ExecuteInContext<B>> SyncLink<'a, B, E> {
 	/// Execute closure with locked ChainSync.
 	fn with_sync<F: Fn(&mut ChainSync<B>, &mut Context<B>)>(&mut self, closure: F) {
 		match *self {
-			#[cfg(test)]
+			#[cfg(any(test, feature = "test-helpers"))]
 			SyncLink::Direct(ref mut sync, ref mut protocol) =>
 				closure(*sync, *protocol),
 			SyncLink::Indirect(ref sync, _, ref service) =>
@@ -417,7 +417,7 @@ impl<'a, B: 'static + BlockT, E: 'a + ExecuteInContext<B>> SyncLink<'a, B, E> {
 impl<'a, B: 'static + BlockT, E: ExecuteInContext<B>> SyncLinkApi<B> for SyncLink<'a, B, E> {
 	fn chain(&self) -> &Client<B> {
 		match *self {
-			#[cfg(test)]
+			#[cfg(any(test, feature = "test-helpers"))]
 			SyncLink::Direct(_, ref protocol) => protocol.client(),
 			SyncLink::Indirect(_, ref chain, _) => *chain,
 		}
@@ -447,6 +447,40 @@ impl<'a, B: 'static + BlockT, E: ExecuteInContext<B>> SyncLinkApi<B> for SyncLin
 	}
 }
 
+
+/// Blocks import queue that is importing blocks in the same thread.
+/// The boolean value indicates whether blocks should be imported without instant finality.
+#[cfg(any(test, feature = "test-helpers"))]
+pub struct SyncImportQueue(pub bool);
+
+#[cfg(any(test, feature = "test-helpers"))]
+impl<B: 'static + BlockT> ImportQueue<B> for SyncImportQueue {
+	fn clear(&self) { }
+
+	fn stop(&self) { }
+
+	fn status(&self) -> ImportQueueStatus<B> {
+		ImportQueueStatus {
+			importing_count: 0,
+			best_importing_number: Zero::zero(),
+		}
+	}
+
+	fn is_importing(&self, _hash: &B::Hash) -> bool {
+		false
+	}
+
+	fn import_blocks(&self, sync: &mut ChainSync<B>, protocol: &mut Context<B>, blocks: (BlockOrigin, Vec<BlockData<B>>)) {
+		struct DummyExecuteInContext;
+
+		impl<B: 'static + BlockT> ExecuteInContext<B> for DummyExecuteInContext {
+			fn execute_in_context<F: Fn(&mut Context<B>)>(&self, _closure: F) { }
+		}
+
+		import_many_blocks(&mut SyncLink::Direct::<_, DummyExecuteInContext>(sync, protocol), None, blocks, self.0);
+	}
+}
+
 #[cfg(test)]
 pub mod tests {
 	use client;
@@ -457,35 +491,6 @@ pub mod tests {
 	use runtime_primitives::generic::BlockId;
 	use super::*;
 
-	/// Blocks import queue that is importing blocks in the same thread.
-	/// The boolean value indicates whether blocks should be imported without instant finality.
-	pub struct SyncImportQueue(pub bool);
-	struct DummyExecuteInContext;
-
-	impl<B: 'static + BlockT> ExecuteInContext<B> for DummyExecuteInContext {
-		fn execute_in_context<F: Fn(&mut Context<B>)>(&self, _closure: F) { }
-	}
-
-	impl<B: 'static + BlockT> ImportQueue<B> for SyncImportQueue {
-		fn clear(&self) { }
-
-		fn stop(&self) { }
-
-		fn status(&self) -> ImportQueueStatus<B> {
-			ImportQueueStatus {
-				importing_count: 0,
-				best_importing_number: Zero::zero(),
-			}
-		}
-
-		fn is_importing(&self, _hash: &B::Hash) -> bool {
-			false
-		}
-
-		fn import_blocks(&self, sync: &mut ChainSync<B>, protocol: &mut Context<B>, blocks: (BlockOrigin, Vec<BlockData<B>>)) {
-			import_many_blocks(&mut SyncLink::Direct::<_, DummyExecuteInContext>(sync, protocol), None, blocks, self.0);
-		}
-	}
 
 	struct TestLink {
 		chain: Arc<Client<Block>>,

substrate/core/network/src/lib.rs

@@ -37,9 +37,14 @@ extern crate rand;
 #[macro_use] extern crate error_chain;
 #[macro_use] extern crate parity_codec_derive;
 
-#[cfg(test)] extern crate env_logger;
+#[cfg(test)]
-#[cfg(test)] extern crate substrate_keyring as keyring;
+extern crate env_logger;
-#[cfg(test)] extern crate substrate_test_client as test_client;
+
+#[cfg(any(test, feature = "test-helpers"))]
+extern crate substrate_keyring as keyring;
+
+#[cfg(any(test, feature = "test-helpers"))]
+extern crate substrate_test_client as test_client;
 
 mod service;
 mod sync;
@@ -55,7 +60,8 @@ pub mod error;
 pub mod message;
 pub mod specialization;
 
-#[cfg(test)] mod test;
+#[cfg(any(test, feature = "test-helpers"))]
+pub mod test;
 
 pub use chain::Client as ClientHandle;
 pub use service::{Service, FetchFuture, ConsensusService, BftMessageStream,

substrate/core/network/src/test/mod.rs

@@ -14,6 +14,9 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
+#![allow(missing_docs)]
+
+#[cfg(test)]
 mod sync;
 
 use std::collections::{VecDeque, HashSet, HashMap};
@@ -22,7 +25,6 @@ use std::sync::Arc;
 use parking_lot::RwLock;
 use client;
 use client::block_builder::BlockBuilder;
-use runtime_primitives::traits::Block as BlockT;
 use runtime_primitives::generic::BlockId;
 use io::SyncIo;
 use protocol::{Context, Protocol};
@@ -31,27 +33,45 @@ use config::ProtocolConfig;
 use service::TransactionPool;
 use network_libp2p::{NodeIndex, SessionInfo, Severity};
 use keyring::Keyring;
-use codec::Encode;
+use codec::{Encode, Decode};
-use import_queue::tests::SyncImportQueue;
+use import_queue::SyncImportQueue;
 use test_client::{self, TestClient};
-use test_client::runtime::{Block, Hash, Transfer, Extrinsic};
 use specialization::Specialization;
+use consensus_gossip::ConsensusGossip;
 
-pub struct DummySpecialization;
+pub use test_client::runtime::{Block, Hash, Transfer, Extrinsic};
+
+/// The test specialization.
+pub struct DummySpecialization {
+	/// Consensus gossip handle.
+	pub gossip: ConsensusGossip<Block>,
+}
+
+#[derive(Encode, Decode)]
+pub struct GossipMessage {
+	/// The topic to classify under.
+	pub topic: Hash,
+	/// The data to send.
+	pub data: Vec<u8>,
+}
 
 impl Specialization<Block> for DummySpecialization {
 	fn status(&self) -> Vec<u8> { vec![] }
 
-	fn on_connect(&mut self, _ctx: &mut Context<Block>, _peer_id: NodeIndex, _status: ::message::Status<Block>) {
+	fn on_connect(&mut self, ctx: &mut Context<Block>, peer_id: NodeIndex, status: ::message::Status<Block>) {
-
+		self.gossip.new_peer(ctx, peer_id, status.roles);
 	}
 
-	fn on_disconnect(&mut self, _ctx: &mut Context<Block>, _peer_id: NodeIndex) {
+	fn on_disconnect(&mut self, ctx: &mut Context<Block>, peer_id: NodeIndex) {
-
+		self.gossip.peer_disconnected(ctx, peer_id);
 	}
 
-	fn on_message(&mut self, _ctx: &mut Context<Block>, _peer_id: NodeIndex, _message: ::message::Message<Block>) {
+	fn on_message(&mut self, ctx: &mut Context<Block>, peer_id: NodeIndex, message: ::message::Message<Block>) {
-
+		if let ::message::generic::Message::ChainSpecific(data) = message {
+			let gossip_message = GossipMessage::decode(&mut &data[..])
+				.expect("gossip messages all in known format; qed");
+			self.gossip.on_chain_specific(ctx, peer_id, data, gossip_message.topic)
+		}
 	}
 }
 
@@ -173,19 +193,30 @@ impl Peer {
 	fn flush(&self) {
 	}
 
-	fn generate_blocks<F>(&self, count: usize, mut edit_block: F) 
+	/// Push a message into the gossip network and relay to peers.
+	/// `TestNet::sync_step` needs to be called to ensure it's propagated.
+	pub fn gossip_message(&self, topic: Hash, data: Vec<u8>) {
+		self.sync.with_spec(&mut TestIo::new(&self.queue, None), |spec, ctx| {
+			let message = GossipMessage { topic, data }.encode();
+			spec.gossip.multicast_chain_specific(ctx, message, topic);
+		})
+	}
+
+	/// Add blocks to the peer -- edit the block before adding
+	pub fn generate_blocks<F>(&self, count: usize, mut edit_block: F)
 	where F: FnMut(&mut BlockBuilder<test_client::Backend, test_client::Executor, Block, Blake2Hasher>)
 	{
 		for _ in 0 .. count {
 			let mut builder = self.client.new_block().unwrap();
 			edit_block(&mut builder);
 			let block = builder.bake().unwrap();
-			trace!("Generating {}, (#{})", block.hash(), block.header.number);
+			trace!("Generating {}, (#{}, parent={})", block.header.hash(), block.header.number, block.header.parent_hash);
 			self.client.justify_and_import(client::BlockOrigin::File, block).unwrap();
 		}
 	}
 
-	fn push_blocks(&self, count: usize, with_tx: bool) {
+	/// Push blocks to the peer (simplified: with or without a TX)
+	pub fn push_blocks(&self, count: usize, with_tx: bool) {
 		let mut nonce = 0;
 		if with_tx {
 			self.generate_blocks(count, |builder| {
@@ -203,6 +234,18 @@ impl Peer {
 			self.generate_blocks(count, |_| ());
 		}
 	}
+
+	/// Execute a function with specialization for this peer.
+	pub fn with_spec<F, U>(&self, f: F) -> U
+		where F: FnOnce(&mut DummySpecialization, &mut Context<Block>) -> U
+	{
+		self.sync.with_spec(&mut TestIo::new(&self.queue, None), f)
+	}
+
+	/// Get a reference to the client.
+	pub fn client(&self) -> &Arc<client::Client<test_client::Backend, test_client::Executor, Block>> {
+		&self.client
+	}
 }
 
 pub struct EmptyTransactionPool;
@@ -226,11 +269,13 @@ pub struct TestNet {
 }
 
 impl TestNet {
-	fn new(n: usize) -> Self {
+	/// Create new test network with this many peers.
+	pub fn new(n: usize) -> Self {
 		Self::new_with_config(n, ProtocolConfig::default())
 	}
 
-	fn new_with_config(n: usize, config: ProtocolConfig) -> Self {
+	/// Create new test network with peers and given config.
+	pub fn new_with_config(n: usize, config: ProtocolConfig) -> Self {
 		let mut net = TestNet {
 			peers: Vec::new(),
 			started: false,
@@ -243,11 +288,23 @@ impl TestNet {
 		net
 	}
 
+	/// Add a peer.
 	pub fn add_peer(&mut self, config: &ProtocolConfig) {
 		let client = Arc::new(test_client::new());
 		let tx_pool = Arc::new(EmptyTransactionPool);
 		let import_queue = Arc::new(SyncImportQueue(false));
-		let sync = Protocol::new(config.clone(), client.clone(), import_queue, None, tx_pool, DummySpecialization).unwrap();
+		let specialization = DummySpecialization {
+			gossip: ConsensusGossip::new(),
+		};
+		let sync = Protocol::new(
+			config.clone(),
+			client.clone(),
+			import_queue,
+			None,
+			tx_pool,
+			specialization
+		).unwrap();
+
 		self.peers.push(Arc::new(Peer {
 			sync: sync,
 			client: client,
@@ -255,10 +312,12 @@ impl TestNet {
 		}));
 	}
 
+	/// Get reference to peer.
 	pub fn peer(&self, i: usize) -> &Peer {
 		&self.peers[i]
 	}
 
+	/// Start network.
 	fn start(&mut self) {
 		if self.started {
 			return;
@@ -274,7 +333,8 @@ impl TestNet {
 		self.started = true;
 	}
 
-	fn sync_step(&mut self) {
+	/// Do one step of routing.
+	pub fn route(&mut self) {
 		for peer in 0..self.peers.len() {
 			let packet = self.peers[peer].pending_message();
 			if let Some(packet) = packet {
@@ -294,20 +354,32 @@ impl TestNet {
 					self.peers[*d].on_disconnect(peer as NodeIndex);
 				}
 			}
-
-			self.sync_step_peer(peer);
 		}
 	}
 
-	fn sync_step_peer(&mut self, peer_num: usize) {
+	/// Route messages between peers until all queues are empty.
-		self.peers[peer_num].sync_step();
+	pub fn route_until_complete(&mut self) {
+		while !self.done() {
+			self.route()
+		}
 	}
 
-	fn restart_peer(&mut self, i: usize) {
+	/// Do a step of synchronization.
+	pub fn sync_step(&mut self) {
+		self.route();
+
+		for peer in &mut self.peers {
+			peer.sync_step();
+		}
+	}
+
+	/// Restart sync for a peer.
+	pub fn restart_peer(&mut self, i: usize) {
 		self.peers[i].restart_sync();
 	}
 
-	fn sync(&mut self) -> u32 {
+	/// Perform synchronization until complete.
+	pub fn sync(&mut self) -> u32 {
 		self.start();
 		let mut total_steps = 0;
 		while !self.done() {
@@ -317,14 +389,16 @@ impl TestNet {
 		total_steps
 	}
 
-	fn sync_steps(&mut self, count: usize) {
+	/// Do the given amount of sync steps.
+	pub fn sync_steps(&mut self, count: usize) {
 		self.start();
 		for _ in 0..count {
 			self.sync_step();
 		}
 	}
 
-	fn done(&self) -> bool {
+	/// Whether all peers have synced.
+	pub fn done(&self) -> bool {
 		self.peers.iter().all(|p| p.is_done())
 	}
 }

substrate/node/network/src/lib.rs

@@ -68,7 +68,8 @@ impl Protocol {
 	fn new_consensus(&mut self, parent_hash: Hash) {
 		let old_consensus = self.live_consensus.take();
 		self.live_consensus = Some(parent_hash);
-		self.consensus_gossip.collect_garbage(old_consensus.as_ref());
+		self.consensus_gossip
+			.collect_garbage(|topic| old_consensus.as_ref().map_or(true, |h| topic != h));
 	}
 }
 
@@ -105,7 +106,7 @@ impl Specialization<Block> for Protocol {
 	}
 
 	fn maintain_peers(&mut self, _ctx: &mut Context<Block>) {
-		self.consensus_gossip.collect_garbage(None);
+		self.consensus_gossip.collect_garbage(|_| true);
 	}
 
 	fn on_block_imported(&mut self, _ctx: &mut Context<Block>, _hash: Hash, _header: &Header) {