ensure that the bridge GRANDPA pallet is initialized in the finality …

…relay (paritytech#1423)

bridges/relays/client-substrate/src/error.rs

@@ -54,6 +54,9 @@ pub enum Error {
 	/// The bridge pallet is halted and all transactions will be rejected.
 	#[error("Bridge pallet is halted.")]
 	BridgePalletIsHalted,
+	/// The bridge pallet is not yet initialized and all transactions will be rejected.
+	#[error("Bridge pallet is not initialized.")]
+	BridgePalletIsNotInitialized,
 	/// An error has happened when we have tried to parse storage proof.
 	#[error("Error when parsing storage proof: {0:?}.")]
 	StorageProofError(bp_runtime::StorageProofError),

bridges/relays/lib-substrate-relay/src/finality/initialize.rs

@@ -110,7 +110,11 @@ where
 }
 
 /// Returns `Ok(true)` if bridge has already been initialized.
-async fn is_initialized<E: Engine<SourceChain>, SourceChain: Chain, TargetChain: Chain>(
+pub(crate) async fn is_initialized<
+	E: Engine<SourceChain>,
+	SourceChain: Chain,
+	TargetChain: Chain,
+>(
 	target_client: &Client<TargetChain>,
 ) -> Result<bool, Error<HashOf<SourceChain>, BlockNumberOf<SourceChain>>> {
 	Ok(target_client

bridges/relays/lib-substrate-relay/src/finality/target.rs

@@ -53,10 +53,20 @@ impl<P: SubstrateFinalitySyncPipeline> SubstrateFinalityTarget<P> {
 	pub async fn ensure_pallet_active(&self) -> Result<(), Error> {
 		let is_halted = self.client.storage_value(P::FinalityEngine::is_halted_key(), None).await?;
 		if is_halted.unwrap_or(false) {
-			Err(Error::BridgePalletIsHalted)
-		} else {
-			Ok(())
+			return Err(Error::BridgePalletIsHalted)
 		}
+
+		let is_initialized =
+			super::initialize::is_initialized::<P::FinalityEngine, P::SourceChain, P::TargetChain>(
+				&self.client,
+			)
+			.await
+			.map_err(|e| Error::Custom(e.to_string()))?;
+		if !is_initialized {
+			return Err(Error::BridgePalletIsNotInitialized)
+		}
+
+		Ok(())
 	}
 }