refactor(base_layer): remove optional finality

crates/papyrus_base_layer/src/base_layer_test.rs

@@ -86,13 +86,13 @@ async fn latest_proved_block_ethereum() {
     let second_sn_state_update = (BlockNumber(200), BlockHash(felt!("0x200")));
     let third_sn_state_update = (BlockNumber(300), BlockHash(felt!("0x300")));
 
-    type Scenario = (Option<u64>, Option<(BlockNumber, BlockHash)>);
+    type Scenario = (u64, Option<(BlockNumber, BlockHash)>);
     let scenarios: Vec<Scenario> = vec![
-        (None, Some(third_sn_state_update)),
-        (Some(5), Some(third_sn_state_update)),
-        (Some(15), Some(second_sn_state_update)),
-        (Some(25), Some(first_sn_state_update)),
-        (Some(1000), None),
+        (0, Some(third_sn_state_update)),
+        (5, Some(third_sn_state_update)),
+        (15, Some(second_sn_state_update)),
+        (25, Some(first_sn_state_update)),
+        (1000, None),
     ];
     for (scenario, expected) in scenarios {
         let latest_block = contract.latest_proved_block(scenario).await.unwrap();

crates/papyrus_base_layer/src/ethereum_base_layer_contract.rs

@@ -97,16 +97,14 @@ impl EthereumBaseLayerContract {
 impl BaseLayerContract for EthereumBaseLayerContract {
     type Error = EthereumBaseLayerError;
 
+    /// Returns the latest proved block on Ethereum, where finality determines how many
+    /// blocks back (0 = latest).
     async fn latest_proved_block(
         &self,
-        finality: Option<u64>,
+        finality: u64,
     ) -> Result<Option<(BlockNumber, BlockHash)>, Self::Error> {
-        let ethereum_block_number = self
-            .contract
-            .provider()
-            .get_block_number()
-            .await?
-            .checked_sub(finality.unwrap_or_default());
+        let ethereum_block_number =
+            self.contract.provider().get_block_number().await?.checked_sub(finality);
         let Some(ethereum_block_number) = ethereum_block_number else {
             return Ok(None);
         };

crates/papyrus_base_layer/src/lib.rs

@@ -15,6 +15,6 @@ pub trait BaseLayerContract {
     /// Optionally, require minimum confirmations.
     async fn latest_proved_block(
         &self,
-        finality: Option<u64>,
+        finality: u64,
     ) -> Result<Option<(BlockNumber, BlockHash)>, Self::Error>;
 }

crates/papyrus_sync/src/sources/base_layer.rs

@@ -36,7 +36,8 @@ impl<
     async fn latest_proved_block(
         &self,
     ) -> Result<Option<(BlockNumber, BlockHash)>, BaseLayerSourceError> {
-        self.latest_proved_block(None)
+        let finality = 0;
+        self.latest_proved_block(finality)
             .await
             .map_err(|e| BaseLayerSourceError::BaseLayerContractError(Box::new(e)))
     }