collation-generation: Support compressed PoVs directly (#4825)

This adds support for returning a compressed PoV directly to the
collation generation. This is mainly to not requiring to compress a PoV
twice.

polkadot/node/collation-generation/src/lib.rs

@@ -309,9 +309,7 @@ async fn handle_new_activations<Context: SubsystemContext>(
 
 					// Apply compression to the block data.
 					let pov = {
-						let pov = polkadot_node_primitives::maybe_compress_pov(
-							collation.proof_of_validity,
-						);
+						let pov = collation.proof_of_validity.into_compressed();
 						let encoded_size = pov.encoded_size();
 
 						// As long as `POV_BOMB_LIMIT` is at least `max_pov_size`, this ensures

polkadot/node/collation-generation/src/tests.rs

@@ -22,7 +22,9 @@ mod handle_new_activations {
 		task::{Context as FuturesContext, Poll},
 		Future,
 	};
-	use polkadot_node_primitives::{BlockData, Collation, CollationResult, PoV, POV_BOMB_LIMIT};
+	use polkadot_node_primitives::{
+		BlockData, Collation, CollationResult, MaybeCompressedPoV, PoV,
+	};
 	use polkadot_node_subsystem::{
 		errors::RuntimeApiError,
 		messages::{AllMessages, RuntimeApiMessage, RuntimeApiRequest},
@@ -41,7 +43,7 @@ mod handle_new_activations {
 			horizontal_messages: vec![],
 			new_validation_code: None,
 			head_data: dummy_head_data(),
-			proof_of_validity: PoV { block_data: BlockData(Vec::new()) },
+			proof_of_validity: MaybeCompressedPoV::Raw(PoV { block_data: BlockData(Vec::new()) }),
 			processed_downward_messages: 0_u32,
 			hrmp_watermark: 0_u32.into(),
 		}
@@ -49,16 +51,8 @@ mod handle_new_activations {
 
 	fn test_collation_compressed() -> Collation {
 		let mut collation = test_collation();
-		let compressed = PoV {
-			block_data: BlockData(
-				sp_maybe_compressed_blob::compress(
-					&collation.proof_of_validity.block_data.0,
-					POV_BOMB_LIMIT,
-				)
-				.unwrap(),
-			),
-		};
-		collation.proof_of_validity = compressed;
+		let compressed = collation.proof_of_validity.clone().into_compressed();
+		collation.proof_of_validity = MaybeCompressedPoV::Compressed(compressed);
 		collation
 	}
 
@@ -309,7 +303,8 @@ mod handle_new_activations {
 		// we expect a single message to be sent, containing a candidate receipt.
 		// we don't care too much about the `commitments_hash` right now, but let's ensure that we've calculated the
 		// correct descriptor
-		let expect_pov_hash = test_collation_compressed().proof_of_validity.hash();
+		let expect_pov_hash =
+			test_collation_compressed().proof_of_validity.into_compressed().hash();
 		let expect_validation_data_hash = test_validation_data().hash();
 		let expect_relay_parent = Hash::repeat_byte(4);
 		let expect_validation_code_hash = ValidationCode(vec![1, 2, 3]).hash();

polkadot/node/primitives/src/lib.rs

@@ -257,6 +257,29 @@ impl PoV {
 	}
 }
 
+/// A type that represents a maybe compressed [`PoV`].
+#[derive(Clone, Encode, Decode)]
+#[cfg(not(target_os = "unknown"))]
+pub enum MaybeCompressedPoV {
+	/// A raw [`PoV`], aka not compressed.
+	Raw(PoV),
+	/// The given [`PoV`] is already compressed.
+	Compressed(PoV),
+}
+
+#[cfg(not(target_os = "unknown"))]
+impl MaybeCompressedPoV {
+	/// Convert into a compressed [`PoV`].
+	///
+	/// If `self == Raw` it is compressed using [`maybe_compress_pov`].
+	pub fn into_compressed(self) -> PoV {
+		match self {
+			Self::Raw(raw) => maybe_compress_pov(raw),
+			Self::Compressed(compressed) => compressed,
+		}
+	}
+}
+
 /// The output of a collator.
 ///
 /// This differs from `CandidateCommitments` in two ways:
@@ -264,6 +287,7 @@ impl PoV {
 /// - does not contain the erasure root; that's computed at the Polkadot level, not at Cumulus
 /// - contains a proof of validity.
 #[derive(Clone, Encode, Decode)]
+#[cfg(not(target_os = "unknown"))]
 pub struct Collation<BlockNumber = polkadot_primitives::v1::BlockNumber> {
 	/// Messages destined to be interpreted by the Relay chain itself.
 	pub upward_messages: Vec<UpwardMessage>,
@@ -274,7 +298,7 @@ pub struct Collation<BlockNumber = polkadot_primitives::v1::BlockNumber> {
 	/// The head-data produced as a result of execution.
 	pub head_data: HeadData,
 	/// Proof to verify the state transition of the parachain.
-	pub proof_of_validity: PoV,
+	pub proof_of_validity: MaybeCompressedPoV,
 	/// The number of messages processed from the DMQ.
 	pub processed_downward_messages: u32,
 	/// The mark which specifies the block number up to which all inbound HRMP messages are processed.
@@ -283,6 +307,7 @@ pub struct Collation<BlockNumber = polkadot_primitives::v1::BlockNumber> {
 
 /// Signal that is being returned when a collation was seconded by a validator.
 #[derive(Debug)]
+#[cfg(not(target_os = "unknown"))]
 pub struct CollationSecondedSignal {
 	/// The hash of the relay chain block that was used as context to sign [`Self::statement`].
 	pub relay_parent: Hash,
@@ -293,6 +318,7 @@ pub struct CollationSecondedSignal {
 }
 
 /// Result of the [`CollatorFn`] invocation.
+#[cfg(not(target_os = "unknown"))]
 pub struct CollationResult {
 	/// The collation that was build.
 	pub collation: Collation,
@@ -304,6 +330,7 @@ pub struct CollationResult {
 	pub result_sender: Option<futures::channel::oneshot::Sender<CollationSecondedSignal>>,
 }
 
+#[cfg(not(target_os = "unknown"))]
 impl CollationResult {
 	/// Convert into the inner values.
 	pub fn into_inner(
@@ -319,6 +346,7 @@ impl CollationResult {
 /// [`ValidationData`] that provides information about the state of the parachain on the relay chain.
 ///
 /// Returns an optional [`CollationResult`].
+#[cfg(not(target_os = "unknown"))]
 pub type CollatorFn = Box<
 	dyn Fn(
 			Hash,
@@ -329,6 +357,7 @@ pub type CollatorFn = Box<
 >;
 
 /// Configuration for the collation generator
+#[cfg(not(target_os = "unknown"))]
 pub struct CollationGenerationConfig {
 	/// Collator's authentication key, so it can sign things.
 	pub key: CollatorPair,
@@ -338,6 +367,7 @@ pub struct CollationGenerationConfig {
 	pub para_id: ParaId,
 }
 
+#[cfg(not(target_os = "unknown"))]
 impl std::fmt::Debug for CollationGenerationConfig {
 	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 		write!(f, "CollationGenerationConfig {{ ... }}")
@@ -371,8 +401,8 @@ impl Proof {
 	}
 }
 
+/// Possible errors when converting from `Vec<Vec<u8>>` into [`Proof`].
 #[derive(thiserror::Error, Debug)]
-///
 pub enum MerkleProofError {
 	#[error("Merkle max proof depth exceeded {0} > {} .", MERKLE_PROOF_MAX_DEPTH)]
 	/// This error signifies that the Proof length exceeds the trie's max depth

polkadot/parachain/test-parachains/adder/collator/src/lib.rs

@@ -20,7 +20,8 @@ use futures::channel::oneshot;
 use futures_timer::Delay;
 use parity_scale_codec::{Decode, Encode};
 use polkadot_node_primitives::{
-	Collation, CollationResult, CollationSecondedSignal, CollatorFn, PoV, Statement,
+	Collation, CollationResult, CollationSecondedSignal, CollatorFn, MaybeCompressedPoV, PoV,
+	Statement,
 };
 use polkadot_primitives::v1::{CollatorId, CollatorPair};
 use sp_core::{traits::SpawnNamed, Pair};
@@ -175,7 +176,7 @@ impl Collator {
 				horizontal_messages: Vec::new(),
 				new_validation_code: None,
 				head_data: head_data.encode().into(),
-				proof_of_validity: pov.clone(),
+				proof_of_validity: MaybeCompressedPoV::Raw(pov.clone()),
 				processed_downward_messages: 0,
 				hrmp_watermark: validation_data.relay_parent_number,
 			};
@@ -273,11 +274,16 @@ mod tests {
 	fn validate_collation(collator: &Collator, parent_head: HeadData, collation: Collation) {
 		use polkadot_node_core_pvf::testing::validate_candidate;
 
+		let block_data = match collation.proof_of_validity {
+			MaybeCompressedPoV::Raw(pov) => pov.block_data,
+			MaybeCompressedPoV::Compressed(_) => panic!("Only works with uncompressed povs"),
+		};
+
 		let ret_buf = validate_candidate(
 			collator.validation_code(),
 			&ValidationParams {
 				parent_head: parent_head.encode().into(),
-				block_data: collation.proof_of_validity.block_data,
+				block_data,
 				relay_parent_number: 1,
 				relay_parent_storage_root: Default::default(),
 			}