Finalize target block after warp sync (#2696)

* Finalize state after warp sync

* Update cargo.lock

* Apply code review suggestion

Co-authored-by: Sebastian Kunert <skunert49@gmail.com>

* Update lock

---------

Co-authored-by: Sebastian Kunert <skunert49@gmail.com>

cumulus/client/consensus/common/src/level_monitor.rs

@@ -362,14 +362,18 @@ where
 
 	/// Add a new imported block information to the monitor.
 	pub fn block_imported(&mut self, number: NumberFor<Block>, hash: Block::Hash) {
+		let finalized_num = self.backend.blockchain().info().finalized_number;
+
+		if number > finalized_num {
+			// Only blocks above the last finalized block should be added to the monitor
 			self.import_counter += One::one();
 			self.freshness.insert(hash, self.import_counter);
 			self.levels.entry(number).or_default().insert(hash);
+		}
 
-		// Do cleanup once in a while, we are allowed to have some obsolete information.
-		let finalized_num = self.backend.blockchain().info().finalized_number;
 		let delta: u32 = finalized_num.saturating_sub(self.lowest_level).unique_saturated_into();
 		if delta >= CLEANUP_THRESHOLD {
+			// Do cleanup once in a while, we are allowed to have some obsolete information.
 			for i in 0..delta {
 				let number = self.lowest_level + i.unique_saturated_into();
 				self.levels.remove(&number).map(|level| {
@@ -378,7 +382,6 @@ where
 					})
 				});
 			}
-
 			self.lowest_level = finalized_num;
 		}
 	}

cumulus/client/consensus/common/src/lib.rs

@@ -147,6 +147,13 @@ where
 		let hash = params.post_hash();
 		let number = *params.header.number();
 
+		if params.with_state() {
+			// Force imported state finality.
+			// Required for warp sync. We assume that preconditions have been
+			// checked properly and we are importing a finalized block with state.
+			params.finalized = true;
+		}
+
 		// Best block is determined by the relay chain, or if we are doing the initial sync
 		// we import all blocks as new best.
 		params.fork_choice = Some(sc_consensus::ForkChoiceStrategy::Custom(