From 1bcbf1751c6224619873373c7cf071cdebdf56ee Mon Sep 17 00:00:00 2001
From: Danil <deniallugo@gmail.com>
Date: Wed, 28 Feb 2024 13:04:23 +0100
Subject: [PATCH] fix(en): fail fast if we don't request correct number of txs
 from man node (#1269)
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## What ❔
Only the last miniblock in batch can have 0 txs. Fail fast if the main
node returned wrong value

## Why ❔

It allows to find discrepancy faster

## Checklist

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- [ ] Tests for the changes have been added / updated.
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Signed-off-by: Danil <deniallugo@gmail.com>
---
 core/lib/zksync_core/src/sync_layer/fetcher.rs | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/core/lib/zksync_core/src/sync_layer/fetcher.rs b/core/lib/zksync_core/src/sync_layer/fetcher.rs
index a9f162f746b..eb22a87345f 100644
--- a/core/lib/zksync_core/src/sync_layer/fetcher.rs
+++ b/core/lib/zksync_core/src/sync_layer/fetcher.rs
@@ -54,6 +54,16 @@ impl TryFrom<SyncBlock> for FetchedBlock {
     type Error = anyhow::Error;
 
     fn try_from(block: SyncBlock) -> anyhow::Result<Self> {
+        let Some(transactions) = block.transactions else {
+            return Err(anyhow::anyhow!("Transactions are always requested"));
+        };
+
+        if transactions.is_empty() && !block.last_in_batch {
+            return Err(anyhow::anyhow!(
+                "Only last miniblock of the batch can be empty"
+            ));
+        }
+
         Ok(Self {
             number: block.number,
             l1_batch_number: block.l1_batch_number,
@@ -66,9 +76,7 @@ impl TryFrom<SyncBlock> for FetchedBlock {
             fair_pubdata_price: block.fair_pubdata_price,
             virtual_blocks: block.virtual_blocks.unwrap_or(0),
             operator_address: block.operator_address,
-            transactions: block
-                .transactions
-                .context("Transactions are always requested")?,
+            transactions,
         })
     }
 }