Refactor DigestItem (#2108)

* Add `start_aura2`.

* .gitignore patch conflict files

and remove one that accidentally got committed

* Fix build

The tests still don’t work.

* Fix compilation errors

* Fix compile errors (again)

* Try (and fail) to fix tests

* Properly deserialize data

Previously, `DigestItem::Consensus` had no separate `DigestItemType`,
so it did not get properly serialized and deserialized.

* Add extra debug logging.  Always allow old seals.

A `RUST_LOG=substrate_aura_consensus cargo test --all -- --nocapture \
tests::authoring_blocks` revealed that old seals were being and
rejected, causing the test to hang.  As a temporary debug measure, allow
old seals unconditionally, so that CI can test if this fixes the
problem.

* Forcibly disable rejection of old seals

* Use old trait, but newer serialization

The old trait for `CompatibleDigestItem` actually worked.  By changing
its implementation, one can ensure that all *new* seals have the modern
form, but *legacy* seals are still decoded correctly.

* Bump impl version

* Squash spurious deprecation warning

`rustc` should not be emitting a deprecation warning in deprecated
code, but it does, so silence it.

* Rip out unused Cargo feature

* Move AURA to aura_primitives

* Respond to code review

* Wrap overly-long line

* Reduce logging verbosity and add target

* Add dependency on `sr-primitives` to `aura_primitives`

* Fix build

It failed with a message about Cargo.lock being out of date.

* core: aura: rename aura engine id const

* core: aura: remove superfluous logging

* core: primitives: add removed semicolons

* core: aura: remove unused import

* core: network: style fix

* runtime: update wasm blobs

* runtime: bump impl_version

* core: primitives: tag all DigestItemType variants explicitly

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

@@ -39,7 +39,7 @@ use crate::consensus_gossip::ConsensusGossip;
 use crossbeam_channel::{self as channel, Sender, select};
 use futures::Future;
 use futures::sync::{mpsc, oneshot};
-use crate::message::{Message, ConsensusEngineId};
+use crate::message::Message;
 use network_libp2p::PeerId;
 use parity_codec::Encode;
 use parking_lot::{Mutex, RwLock};
@@ -47,7 +47,7 @@ use primitives::{H256, ed25519::Public as AuthorityId};
 use crate::protocol::{ConnectedPeer, Context, FromNetworkMsg, Protocol, ProtocolMsg};
 use runtime_primitives::generic::BlockId;
 use runtime_primitives::traits::{AuthorityIdFor, Block as BlockT, Digest, DigestItem, Header, NumberFor};
-use runtime_primitives::Justification;
+use runtime_primitives::{Justification, ConsensusEngineId};
 use crate::service::{network_channel, NetworkChan, NetworkLink, NetworkMsg, NetworkPort, TransactionPool};
 use crate::specialization::NetworkSpecialization;
 use test_client::{self, AccountKeyring};
@@ -260,11 +260,13 @@ impl<D, S: NetworkSpecialization<Block> + Clone> Peer<D, S> {
 	}
 
 	// SyncOracle: are we connected to any peer?
+	#[cfg(test)]
 	fn is_offline(&self) -> bool {
 		self.is_offline.load(Ordering::Relaxed)
 	}
 
 	// SyncOracle: are we in the process of catching-up with the chain?
+	#[cfg(test)]
 	fn is_major_syncing(&self) -> bool {
 		self.is_major_syncing.load(Ordering::Relaxed)
 	}
@@ -644,7 +646,6 @@ pub trait TestNetFactory: Sized {
 					Some(NetworkMsg::ReportPeer(who, _)) => {
 						to_disconnect.insert(who);
 					}
-					Some(_msg) => continue,
 				}
 			}
 			for d in to_disconnect {