fix(api): Fix batch fee input for debug namespace (#2948)

## What ❔

Changes the `debug_traceCall` handler to use the fee provider for recent
blocks (pending / latest / committed).

## Why ❔

Previously, the `debug` namespace used a static batch fee input
retrieved at the node initialization. This looks incorrect.

## Checklist

- [x] PR title corresponds to the body of PR (we generate changelog
entries from PRs).
- [x] Tests for the changes have been added / updated.
- [x] Documentation comments have been added / updated.
- [x] Code has been formatted via `zk fmt` and `zk lint`.

core/lib/types/src/api/mod.rs

@@ -754,21 +754,17 @@ pub enum CallTracerBlockResult {
 }
 
 impl CallTracerBlockResult {
-    pub fn unwrap_flatten(self) -> Vec<DebugCallFlat> {
+    pub fn unwrap_flat(self) -> Vec<DebugCallFlat> {
         match self {
-            Self::CallTrace(_) => {
-                panic!("Result is a FlatCallTrace")
-            }
-            Self::FlatCallTrace(a) => a,
+            Self::CallTrace(_) => panic!("Result is a FlatCallTrace"),
+            Self::FlatCallTrace(trace) => trace,
         }
     }
 
     pub fn unwrap_default(self) -> Vec<ResultDebugCall> {
         match self {
-            Self::CallTrace(a) => a,
-            Self::FlatCallTrace(_) => {
-                panic!("Result is a CallTrace")
-            }
+            Self::CallTrace(trace) => trace,
+            Self::FlatCallTrace(_) => panic!("Result is a CallTrace"),
         }
     }
 }
@@ -783,19 +779,15 @@ pub enum CallTracerResult {
 impl CallTracerResult {
     pub fn unwrap_flat(self) -> Vec<DebugCallFlat> {
         match self {
-            Self::CallTrace(_) => {
-                panic!("Result is a FlatCallTrace")
-            }
-            Self::FlatCallTrace(a) => a,
+            Self::CallTrace(_) => panic!("Result is a FlatCallTrace"),
+            Self::FlatCallTrace(trace) => trace,
         }
     }
 
     pub fn unwrap_default(self) -> DebugCall {
         match self {
-            Self::CallTrace(a) => a,
-            Self::FlatCallTrace(_) => {
-                panic!("Result is a CallTrace")
-            }
+            Self::CallTrace(trace) => trace,
+            Self::FlatCallTrace(_) => panic!("Result is a CallTrace"),
         }
     }
 }

core/node/api_server/src/web3/namespaces/debug.rs

@@ -8,7 +8,6 @@ use zksync_types::{
         ResultDebugCall, SupportedTracers, TracerConfig,
     },
     debug_flat_call::{Action, CallResult, DebugCallFlat},
-    fee_model::BatchFeeInput,
     l2::L2Tx,
     transaction_request::CallRequest,
     web3, H256, U256,
@@ -22,27 +21,12 @@ use crate::{
 
 #[derive(Debug, Clone)]
 pub(crate) struct DebugNamespace {
-    batch_fee_input: BatchFeeInput,
     state: RpcState,
 }
 
 impl DebugNamespace {
     pub async fn new(state: RpcState) -> anyhow::Result<Self> {
-        let fee_input_provider = &state.tx_sender.0.batch_fee_input_provider;
-        // FIXME (PLA-1033): use the fee input provider instead of a constant value
-        let batch_fee_input = fee_input_provider
-            .get_batch_fee_input_scaled(
-                state.api_config.estimate_gas_scale_factor,
-                state.api_config.estimate_gas_scale_factor,
-            )
-            .await
-            .context("cannot get batch fee input")?;
-
-        Ok(Self {
-            // For now, the same scaling is used for both the L1 gas price and the pubdata price
-            batch_fee_input,
-            state,
-        })
+        Ok(Self { state })
     }
 
     pub(crate) fn map_call(
@@ -257,12 +241,22 @@ impl DebugNamespace {
         if request.gas.is_none() {
             request.gas = Some(block_args.default_eth_call_gas(&mut connection).await?);
         }
+
         let fee_input = if block_args.resolves_to_latest_sealed_l2_block() {
-            self.batch_fee_input
+            // It is important to drop a DB connection before calling the provider, since it acquires a connection internally
+            // on the main node.
+            drop(connection);
+            let scale_factor = self.state.api_config.estimate_gas_scale_factor;
+            let fee_input_provider = &self.state.tx_sender.0.batch_fee_input_provider;
+            // For now, the same scaling is used for both the L1 gas price and the pubdata price
+            fee_input_provider
+                .get_batch_fee_input_scaled(scale_factor, scale_factor)
+                .await?
         } else {
-            block_args.historical_fee_input(&mut connection).await?
+            let fee_input = block_args.historical_fee_input(&mut connection).await?;
+            drop(connection);
+            fee_input
         };
-        drop(connection);
 
         let call_overrides = request.get_call_overrides()?;
         let call = L2Tx::from_request(request.into(), MAX_ENCODED_TX_SIZE)?;

core/node/api_server/src/web3/testonly.rs

@@ -97,42 +97,72 @@ impl ApiServerHandles {
     }
 }
 
-pub async fn spawn_http_server(
-    api_config: InternalApiConfig,
+/// Builder for test server instances.
+#[derive(Debug)]
+pub struct TestServerBuilder {
     pool: ConnectionPool<Core>,
+    api_config: InternalApiConfig,
     tx_executor: MockOneshotExecutor,
     method_tracer: Arc<MethodTracer>,
-    stop_receiver: watch::Receiver<bool>,
-) -> ApiServerHandles {
-    spawn_server(
-        ApiTransportLabel::Http,
-        api_config,
-        pool,
-        None,
-        tx_executor,
-        method_tracer,
-        stop_receiver,
-    )
-    .await
-    .0
 }
 
-pub async fn spawn_ws_server(
-    api_config: InternalApiConfig,
-    pool: ConnectionPool<Core>,
-    stop_receiver: watch::Receiver<bool>,
-    websocket_requests_per_minute_limit: Option<NonZeroU32>,
-) -> (ApiServerHandles, mpsc::UnboundedReceiver<PubSubEvent>) {
-    spawn_server(
-        ApiTransportLabel::Ws,
-        api_config,
-        pool,
-        websocket_requests_per_minute_limit,
-        MockOneshotExecutor::default(),
-        Arc::default(),
-        stop_receiver,
-    )
-    .await
+impl TestServerBuilder {
+    /// Creates a new builder.
+    pub fn new(pool: ConnectionPool<Core>, api_config: InternalApiConfig) -> Self {
+        Self {
+            api_config,
+            pool,
+            tx_executor: MockOneshotExecutor::default(),
+            method_tracer: Arc::default(),
+        }
+    }
+
+    /// Sets a transaction / call executor for this builder.
+    #[must_use]
+    pub fn with_tx_executor(mut self, tx_executor: MockOneshotExecutor) -> Self {
+        self.tx_executor = tx_executor;
+        self
+    }
+
+    /// Sets an RPC method tracer for this builder.
+    #[must_use]
+    pub fn with_method_tracer(mut self, tracer: Arc<MethodTracer>) -> Self {
+        self.method_tracer = tracer;
+        self
+    }
+
+    /// Builds an HTTP server.
+    pub async fn build_http(self, stop_receiver: watch::Receiver<bool>) -> ApiServerHandles {
+        spawn_server(
+            ApiTransportLabel::Http,
+            self.api_config,
+            self.pool,
+            None,
+            self.tx_executor,
+            self.method_tracer,
+            stop_receiver,
+        )
+        .await
+        .0
+    }
+
+    /// Builds a WS server.
+    pub async fn build_ws(
+        self,
+        websocket_requests_per_minute_limit: Option<NonZeroU32>,
+        stop_receiver: watch::Receiver<bool>,
+    ) -> (ApiServerHandles, mpsc::UnboundedReceiver<PubSubEvent>) {
+        spawn_server(
+            ApiTransportLabel::Ws,
+            self.api_config,
+            self.pool,
+            websocket_requests_per_minute_limit,
+            self.tx_executor,
+            self.method_tracer,
+            stop_receiver,
+        )
+        .await
+    }
 }
 
 async fn spawn_server(

core/node/api_server/src/web3/tests/debug.rs

@@ -137,7 +137,7 @@ impl HttpTest for TraceBlockFlatTest {
                         }),
                     )
                     .await?
-                    .unwrap_flatten();
+                    .unwrap_flat();
 
                 // A transaction with 2 nested calls will convert into 3 Flattened calls.
                 // Also in this test, all tx have the same # of nested calls

core/node/api_server/src/web3/tests/mod.rs

@@ -58,7 +58,7 @@ use zksync_web3_decl::{
 };
 
 use super::*;
-use crate::web3::testonly::{spawn_http_server, spawn_ws_server};
+use crate::web3::testonly::TestServerBuilder;
 
 mod debug;
 mod filters;
@@ -245,14 +245,11 @@ async fn test_http_server(test: impl HttpTest) {
     let genesis = GenesisConfig::for_tests();
     let mut api_config = InternalApiConfig::new(&web3_config, &contracts_config, &genesis);
     api_config.filters_disabled = test.filters_disabled();
-    let mut server_handles = spawn_http_server(
-        api_config,
-        pool.clone(),
-        test.transaction_executor(),
-        test.method_tracer(),
-        stop_receiver,
-    )
-    .await;
+    let mut server_handles = TestServerBuilder::new(pool.clone(), api_config)
+        .with_tx_executor(test.transaction_executor())
+        .with_method_tracer(test.method_tracer())
+        .build_http(stop_receiver)
+        .await;
 
     let local_addr = server_handles.wait_until_ready().await;
     let client = Client::http(format!("http://{local_addr}/").parse().unwrap())
@@ -306,6 +303,17 @@ async fn store_l2_block(
     number: L2BlockNumber,
     transaction_results: &[TransactionExecutionResult],
 ) -> anyhow::Result<L2BlockHeader> {
+    let header = create_l2_block(number.0);
+    store_custom_l2_block(storage, &header, transaction_results).await?;
+    Ok(header)
+}
+
+async fn store_custom_l2_block(
+    storage: &mut Connection<'_, Core>,
+    header: &L2BlockHeader,
+    transaction_results: &[TransactionExecutionResult],
+) -> anyhow::Result<()> {
+    let number = header.number;
     for result in transaction_results {
         let l2_tx = result.transaction.clone().try_into().unwrap();
         let tx_submission_result = storage
@@ -328,19 +336,18 @@ async fn store_l2_block(
         .append_storage_logs(number, &[l2_block_log])
         .await?;
 
-    let new_l2_block = create_l2_block(number.0);
-    storage.blocks_dal().insert_l2_block(&new_l2_block).await?;
+    storage.blocks_dal().insert_l2_block(header).await?;
     storage
         .transactions_dal()
         .mark_txs_as_executed_in_l2_block(
-            new_l2_block.number,
+            number,
             transaction_results,
             1.into(),
             ProtocolVersionId::latest(),
             false,
         )
         .await?;
-    Ok(new_l2_block)
+    Ok(())
 }
 
 async fn seal_l1_batch(