refactor(vm-runner): simplify last processed batch query (matter-labs…

…#2373)

## What ❔

Refactors query to not use default param and return `Option` instead

## Why ❔

Transparent flow

## Checklist

<!-- Check your PR fulfills the following items. -->
<!-- For draft PRs check the boxes as you complete them. -->

- [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/dal/src/vm_runner_dal.rs

@@ -11,22 +11,20 @@ pub struct VmRunnerDal<'c, 'a> {
 impl VmRunnerDal<'_, '_> {
     pub async fn get_protective_reads_latest_processed_batch(
         &mut self,
-        default_batch: L1BatchNumber,
-    ) -> DalResult<L1BatchNumber> {
+    ) -> DalResult<Option<L1BatchNumber>> {
         let row = sqlx::query!(
             r#"
             SELECT
-                COALESCE(MAX(l1_batch_number), $1) AS "last_processed_l1_batch!"
+                MAX(l1_batch_number) AS "last_processed_l1_batch"
             FROM
                 vm_runner_protective_reads
-            "#,
-            default_batch.0 as i32
+            "#
         )
         .instrument("get_protective_reads_latest_processed_batch")
         .report_latency()
         .fetch_one(self.storage)
         .await?;
-        Ok(L1BatchNumber(row.last_processed_l1_batch as u32))
+        Ok(row.last_processed_l1_batch.map(|n| L1BatchNumber(n as u32)))
     }
 
     pub async fn get_protective_reads_last_ready_batch(

core/node/metadata_calculator/src/tests.rs

@@ -275,9 +275,10 @@ async fn expected_tree_hash(pool: &ConnectionPool<Core>, sealed_protective_reads
     } else {
         storage
             .vm_runner_dal()
-            .get_protective_reads_latest_processed_batch(L1BatchNumber(0))
+            .get_protective_reads_latest_processed_batch()
             .await
             .unwrap()
+            .unwrap_or_default()
     };
     let mut all_logs = vec![];
     for i in 0..=processed_l1_batch_number.0 {

core/node/metadata_calculator/src/updater.rs

@@ -214,9 +214,10 @@ impl TreeUpdater {
         } else {
             storage
                 .vm_runner_dal()
-                .get_protective_reads_latest_processed_batch(L1BatchNumber(0))
+                .get_protective_reads_latest_processed_batch()
                 .await
                 .context("failed loading latest L1 batch number with protective reads")?
+                .unwrap_or_default()
         };
         drop(storage);
 
@@ -423,8 +424,9 @@ impl AsyncTree {
 
         let current_db_batch = storage
             .vm_runner_dal()
-            .get_protective_reads_latest_processed_batch(L1BatchNumber(0))
-            .await?;
+            .get_protective_reads_latest_processed_batch()
+            .await?
+            .unwrap_or_default();
         let last_l1_batch_with_tree_data = storage
             .blocks_dal()
             .get_last_l1_batch_number_with_tree_data()

core/node/vm_runner/src/impls/protective_reads.rs

@@ -93,8 +93,9 @@ impl VmRunnerIo for ProtectiveReadsIo {
     ) -> anyhow::Result<L1BatchNumber> {
         Ok(conn
             .vm_runner_dal()
-            .get_protective_reads_latest_processed_batch(self.first_processed_batch)
-            .await?)
+            .get_protective_reads_latest_processed_batch()
+            .await?
+            .unwrap_or(self.first_processed_batch))
     }
 
     async fn last_ready_to_be_loaded_batch(