From 62577169d2464e21bbe5af2739e3c3891710a15d Mon Sep 17 00:00:00 2001
From: Rodrigo Quelhas <rodrigo_quelhas@outlook.pt>
Date: Fri, 6 Dec 2024 11:27:25 +0000
Subject: [PATCH] explicitly set fork_chain when sealing a block

---
 .../nimbus-consensus/src/collators.rs         |  2 ++
 .../nimbus-consensus/src/import_queue.rs      | 34 ++++++-------------
 template/node/src/service.rs                  |  2 +-
 3 files changed, 14 insertions(+), 24 deletions(-)

diff --git a/client/consensus/nimbus-consensus/src/collators.rs b/client/consensus/nimbus-consensus/src/collators.rs
index ffaff8a5..7b73cce1 100644
--- a/client/consensus/nimbus-consensus/src/collators.rs
+++ b/client/consensus/nimbus-consensus/src/collators.rs
@@ -118,6 +118,8 @@ where
 	block_import_params.state_action = sc_consensus::StateAction::ApplyChanges(
 		sc_consensus::StorageChanges::Changes(storage_changes),
 	);
+	// The collator should follow the longest chain
+	block_import_params.fork_choice = Some(sc_consensus::ForkChoiceStrategy::LongestChain);
 
 	let post_hash = block_import_params.post_hash();
 
diff --git a/client/consensus/nimbus-consensus/src/import_queue.rs b/client/consensus/nimbus-consensus/src/import_queue.rs
index a3ab8daf..36389e92 100644
--- a/client/consensus/nimbus-consensus/src/import_queue.rs
+++ b/client/consensus/nimbus-consensus/src/import_queue.rs
@@ -200,10 +200,7 @@ pub fn import_queue<Client, Block: BlockT, I, CIDP>(
 	create_inherent_data_providers: CIDP,
 	spawner: &impl sp_core::traits::SpawnEssentialNamed,
 	registry: Option<&substrate_prometheus_endpoint::Registry>,
-	// Deprecated: Using a custom fork strategy for parachain at block
-	// import is no longer necessary.
-	// Context: https://github.com/paritytech/polkadot-sdk/issues/4333
-	use_custom_fork_strategy: Option<bool>,
+	with_delayed_best_block: bool,
 ) -> ClientResult<BasicQueue<Block>>
 where
 	I: BlockImport<Block, Error = ConsensusError> + Send + Sync + 'static,
@@ -217,15 +214,10 @@ where
 		_marker: PhantomData,
 	};
 
-	let block_import_for_queue: sc_consensus::BoxBlockImport<Block> = match use_custom_fork_strategy
-	{
-		Some(parachain_context) =>
-		{
-			#[allow(deprecated)]
-			Box::new(NimbusBlockImport::new(block_import, parachain_context))
-		}
-		None => Box::new(block_import),
-	};
+	let block_import_for_queue = Box::new(NimbusBlockImport::new(
+		block_import,
+		with_delayed_best_block,
+	));
 
 	Ok(BasicQueue::new(
 		verifier,
@@ -245,21 +237,17 @@ where
 ///
 /// There may be additional nimbus-specific logic here in the future, but for now it is
 /// only the conditional parachain logic
-#[deprecated(
-	note = "Aura was using a custom fork strategy for parachain at block import, this is no longer necessary."
-)]
 pub struct NimbusBlockImport<I> {
 	inner: I,
-	parachain_context: bool,
+	with_delayed_best_block: bool,
 }
 
-#[allow(deprecated)]
 impl<I> NimbusBlockImport<I> {
 	/// Create a new instance.
-	pub fn new(inner: I, parachain_context: bool) -> Self {
+	pub fn new(inner: I, with_delayed_best_block: bool) -> Self {
 		Self {
 			inner,
-			parachain_context,
+			with_delayed_best_block,
 		}
 	}
 }
@@ -284,9 +272,9 @@ where
 		&mut self,
 		mut block_import_params: sc_consensus::BlockImportParams<Block>,
 	) -> Result<sc_consensus::ImportResult, Self::Error> {
-		// If we are in the parachain context, best block is determined by the relay chain
-		// except during initial sync
-		if self.parachain_context {
+		// Best block is determined by the relay chain, or if we are doing the initial sync
+		// we import all blocks as new best.
+		if self.with_delayed_best_block {
 			block_import_params.fork_choice = Some(sc_consensus::ForkChoiceStrategy::Custom(
 				block_import_params.origin == sp_consensus::BlockOrigin::NetworkInitialSync,
 			));
diff --git a/template/node/src/service.rs b/template/node/src/service.rs
index 2b0cd5bd..3b543d93 100644
--- a/template/node/src/service.rs
+++ b/template/node/src/service.rs
@@ -156,7 +156,7 @@ pub fn new_partial(
 		},
 		&task_manager.spawn_essential_handle(),
 		config.prometheus_registry().clone(),
-		None,
+		false,
 	)?;
 
 	Ok(PartialComponents {