Storing multiple Justifications per block (#7640)

* primitives/runtime: initial changes on supporting multiple Justifications

* primitives/runtime: make Justifications strongly typed

* Encode/decode Justifications

* primitives/runtime: add Justification type

* backend: apply_finality and finalize_block takes a single Justification

* manual-seal: create engine id and let rpc take encoded justification

* backend: skeleton functions for appending justifications

* backend: initial implementation append_justification

Initial implementation of append_justification on the Backend trait, and also remove unused skeleton
functions for append_justificaton on Finaziler trait.
k

* backend: guard against duplicate consensus engine id

* client/db: add check for block finality

* client/api: add append_justification to in_mem db

* client/light: add no-op append_justification

* network: fix decode call for Justification

* network: only send a single Justification in BlockData

* network: minor comment update

* protocol: update field names to distinguish single justification

* client: further field renames to plural

* client: update function names to plural justifications

* client/db: upgrade existing database for new format

* network: remove dependency on grandpa crate

* db: fix check for finalized block

* grandpa: check for multiple grandpa justifications hwne importing

* backend: update Finalizer trait to take multiple Justifications

* db: remove debugging statements in migration code

* manual-seal: update note about engine id

* db: fix check for finalized block

* client: update variable name to reflect it is now plural

* grandpa: fix incorrect empty Justications in test

* primitives: make Justifications opaque to avoid being empty

* network: fix detecting empty Justification

* runtime: doc strings for Justifications functions

* runtime: add into_justifications

* primitives: check for duplicates in when adding to Justifications

* network/test: use real grandpa engine id in test

* client: fix reviewer comments

* primitives: rename Justifications::push to append

* backend: revert changes to Finalizer trait

* backend: revert mark_finalized

* backend: revert changes to finalize_block

* backend: revert finalized_blocks

* db: add a quick early return for performance

* client: minor reviewer comments

* service/test: use local ConsensusEngineId

* network: add link to issue for sending multiple Justifications

* Apply suggestions from code review

Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>

* Apply suggestions from code review

Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>

* network: tweaks to review suggestions

* network: revert change to BlockData for backwards compatibility

* Apply suggestion from code review

Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>

* Apply suggestions from code review

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

* primitives: update doc comment for Justifications

* client/db/upgrade: avoid grandpa crate dependency

* consensus: revert to single Justification for import_justification

* primitives: improve justifications docs

* style cleanups

* use and_then

* client: rename JUSTIFICATIONS db column

* network: revert to using FRNK in network-test

Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>
Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>
Co-authored-by: André Silva <andrerfosilva@gmail.com>

substrate/test-utils/client/src/client_ext.rs

@@ -24,7 +24,7 @@ use sp_consensus::{
 	BlockImportParams, BlockImport, BlockOrigin, Error as ConsensusError,
 	ForkChoiceStrategy,
 };
-use sp_runtime::Justification;
+use sp_runtime::{Justification, Justifications};
 use sp_runtime::traits::{Block as BlockT};
 use sp_runtime::generic::BlockId;
 use codec::alloc::collections::hash_map::HashMap;
@@ -51,15 +51,14 @@ pub trait ClientBlockImportExt<Block: BlockT>: Sized {
 	fn import_as_best(&mut self, origin: BlockOrigin, block: Block) -> Result<(), ConsensusError>;
 
 	/// Import a block and finalize it.
-	fn import_as_final(&mut self, origin: BlockOrigin, block: Block)
-		-> Result<(), ConsensusError>;
+	fn import_as_final(&mut self, origin: BlockOrigin, block: Block) -> Result<(), ConsensusError>;
 
-	/// Import block with justification, finalizes block.
+	/// Import block with justification(s), finalizes block.
 	fn import_justified(
 		&mut self,
 		origin: BlockOrigin,
 		block: Block,
-		justification: Justification
+		justifications: Justifications,
 	) -> Result<(), ConsensusError>;
 }
 
@@ -119,11 +118,11 @@ impl<Block: BlockT, T, Transaction> ClientBlockImportExt<Block> for std::sync::A
 		&mut self,
 		origin: BlockOrigin,
 		block: Block,
-		justification: Justification,
+		justifications: Justifications,
 	) -> Result<(), ConsensusError> {
 		let (header, extrinsics) = block.deconstruct();
 		let mut import = BlockImportParams::new(origin, header);
-		import.justification = Some(justification);
+		import.justifications = Some(justifications);
 		import.body = Some(extrinsics);
 		import.finalized = true;
 		import.fork_choice = Some(ForkChoiceStrategy::LongestChain);
@@ -168,11 +167,11 @@ impl<B, E, RA, Block: BlockT> ClientBlockImportExt<Block> for Client<B, E, Block
 		&mut self,
 		origin: BlockOrigin,
 		block: Block,
-		justification: Justification,
+		justifications: Justifications,
 	) -> Result<(), ConsensusError> {
 		let (header, extrinsics) = block.deconstruct();
 		let mut import = BlockImportParams::new(origin, header);
-		import.justification = Some(justification);
+		import.justifications = Some(justifications);
 		import.body = Some(extrinsics);
 		import.finalized = true;
 		import.fork_choice = Some(ForkChoiceStrategy::LongestChain);