Allow import withouth state verification (#4031)

* Allow import without state verification

* Explicit None

Co-Authored-By: Robert Habermeier <rphmeier@gmail.com>

substrate/core/consensus/aura/src/lib.rs

@@ -267,6 +267,7 @@ impl<H, B, C, E, I, P, Error, SO> slots::SimpleSlotWorker<B> for AuraWorker<C, E
 				finalized: false,
 				auxiliary: Vec::new(),
 				fork_choice: ForkChoiceStrategy::LongestChain,
+				allow_missing_state: false,
 			}
 		})
 	}
@@ -570,6 +571,7 @@ impl<B: BlockT, C, P, T> Verifier<B> for AuraVerifier<C, P, T> where
 					justification,
 					auxiliary: Vec::new(),
 					fork_choice: ForkChoiceStrategy::LongestChain,
+					allow_missing_state: false,
 				};
 
 				Ok((block_import_params, maybe_keys))

substrate/core/consensus/babe/src/lib.rs

@@ -430,6 +430,7 @@ impl<B, C, E, I, Error, SO> slots::SimpleSlotWorker<B> for BabeWorker<B, C, E, I
 				// option to specify one.
 				// https://github.com/paritytech/substrate/issues/3623
 				fork_choice: ForkChoiceStrategy::LongestChain,
+				allow_missing_state: false,
 			}
 		})
 	}
@@ -741,6 +742,7 @@ impl<B, E, Block, RA, PRA> Verifier<Block> for BabeVerifier<B, E, Block, RA, PRA
 					// option to specify one.
 					// https://github.com/paritytech/substrate/issues/3623
 					fork_choice: ForkChoiceStrategy::LongestChain,
+					allow_missing_state: false,
 				};
 
 				Ok((block_import_params, Default::default()))

substrate/core/consensus/babe/src/tests.rs

@@ -578,6 +578,7 @@ fn propose_and_import_block(
 			finalized: false,
 			auxiliary: Vec::new(),
 			fork_choice: ForkChoiceStrategy::LongestChain,
+			allow_missing_state: false,
 		},
 		Default::default(),
 	).unwrap();

substrate/core/consensus/common/src/block_import.rs

@@ -35,11 +35,15 @@ pub enum ImportResult {
 	KnownBad,
 	/// Block parent is not in the chain.
 	UnknownParent,
+	/// Parent state is missing.
+	MissingState,
 }
 
 /// Auxiliary data associated with an imported block result.
 #[derive(Debug, Default, PartialEq, Eq)]
 pub struct ImportedAux {
+	/// Only the header has been imported. Block body verification was skipped.
+	pub header_only: bool,
 	/// Clear all pending justification requests.
 	pub clear_justification_requests: bool,
 	/// Request a justification for the given block.
@@ -98,6 +102,8 @@ pub struct BlockCheckParams<Block: BlockT> {
 	pub number: NumberFor<Block>,
 	/// Parent hash of the block that we verify.
 	pub parent_hash: Block::Hash,
+	/// Allow importing the block skipping state verification if parent state is missing.
+	pub allow_missing_state: bool,
 }
 
 /// Data required to import a Block.
@@ -133,6 +139,8 @@ pub struct BlockImportParams<Block: BlockT> {
 	/// Fork choice strategy of this import. This should only be set by a
 	/// synchronous import, otherwise it may race against other imports.
 	pub fork_choice: ForkChoiceStrategy,
+	/// Allow importing the block skipping state verification if parent state is missing.
+	pub allow_missing_state: bool,
 }
 
 impl<Block: BlockT> BlockImportParams<Block> {

substrate/core/consensus/common/src/import_queue.rs

@@ -63,6 +63,8 @@ pub struct IncomingBlock<B: BlockT> {
 	pub justification: Option<Justification>,
 	/// The peer, we received this from
 	pub origin: Option<Origin>,
+	/// Allow importing the block skipping state verification if parent state is missing.
+	pub allow_missing_state: bool,
 }
 
 /// Type of keys in the blockchain cache that consensus module could use for its needs.
@@ -203,6 +205,10 @@ pub fn import_single_block<B: BlockT, V: Verifier<B>>(
 				Ok(BlockImportResult::ImportedKnown(number))
 			},
 			Ok(ImportResult::Imported(aux)) => Ok(BlockImportResult::ImportedUnknown(number, aux, peer.clone())),
+			Ok(ImportResult::MissingState) => {
+				debug!(target: "sync", "Parent state is missing for {}: {:?}, parent: {:?}", number, hash, parent_hash);
+				Err(BlockImportError::UnknownParent)
+			},
 			Ok(ImportResult::UnknownParent) => {
 				debug!(target: "sync", "Block with unknown parent {}: {:?}, parent: {:?}", number, hash, parent_hash);
 				Err(BlockImportError::UnknownParent)
@@ -217,12 +223,17 @@ pub fn import_single_block<B: BlockT, V: Verifier<B>>(
 			}
 		}
 	};
-	match import_error(import_handle.check_block(BlockCheckParams { hash, number, parent_hash }))? {
+	match import_error(import_handle.check_block(BlockCheckParams {
+		hash,
+		number,
+		parent_hash,
+		allow_missing_state: block.allow_missing_state,
+	}))? {
 		BlockImportResult::ImportedUnknown { .. } => (),
 		r => return Ok(r), // Any other successful result means that the block is already imported.
 	}
 
-	let (import_block, maybe_keys) = verifier.verify(block_origin, header, justification, block.body)
+	let (mut import_block, maybe_keys) = verifier.verify(block_origin, header, justification, block.body)
 		.map_err(|msg| {
 			if let Some(ref peer) = peer {
 				trace!(target: "sync", "Verifying {}({}) from {} failed: {}", number, hash, peer, msg);
@@ -236,6 +247,7 @@ pub fn import_single_block<B: BlockT, V: Verifier<B>>(
 	if let Some(keys) = maybe_keys {
 		cache.extend(keys.into_iter());
 	}
+	import_block.allow_missing_state = block.allow_missing_state;
 
 	import_error(import_handle.import_block(import_block, cache))
 }

substrate/core/consensus/pow/src/lib.rs

@@ -304,6 +304,7 @@ impl<B: BlockT<Hash=H256>, C, S, Algorithm> Verifier<B> for PowVerifier<B, C, S,
 			justification,
 			auxiliary: vec![(key, Some(aux.encode()))],
 			fork_choice: ForkChoiceStrategy::Custom(aux.total_difficulty > best_aux.total_difficulty),
+			allow_missing_state: false,
 		};
 
 		Ok((import_block, None))
@@ -531,6 +532,7 @@ fn mine_loop<B: BlockT<Hash=H256>, C, Algorithm, E, SO, S>(
 			finalized: false,
 			auxiliary: vec![(key, Some(aux.encode()))],
 			fork_choice: ForkChoiceStrategy::Custom(true),
+			allow_missing_state: false,
 		};
 
 		block_import.import_block(import_block, HashMap::default())