From a2f9f8c61e1e5ef7923de20d4d6c899a015eb74d Mon Sep 17 00:00:00 2001
From: Vitaly Drogan <vitaliy.drogan@gmail.com>
Date: Sat, 26 Jun 2021 12:56:40 +0300
Subject: [PATCH 1/2] Add handling of priority queue gap in eth_watch

---
 core/bin/zksync_core/src/eth_watch/mod.rs | 26 ++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/core/bin/zksync_core/src/eth_watch/mod.rs b/core/bin/zksync_core/src/eth_watch/mod.rs
index 0e07fa419b..63e7d664c9 100644
--- a/core/bin/zksync_core/src/eth_watch/mod.rs
+++ b/core/bin/zksync_core/src/eth_watch/mod.rs
@@ -149,13 +149,24 @@ impl<W: EthClient> EthWatch<W> {
 
         // Extend the existing priority operations with the new ones.
         let mut priority_queue = sift_outdated_ops(self.eth_state.priority_queue());
-        let new_priority_op_ids: Vec<_> = priority_queue.keys().cloned().collect();
-        vlog::debug!("New priority ops added: {:?}", new_priority_op_ids);
 
         for (serial_id, op) in received_priority_queue {
             priority_queue.insert(serial_id, op);
         }
 
+        // Check for gaps in priority queue. If some event is missing we skip this `ETHState` update.
+        let mut priority_op_ids: Vec<_> = priority_queue.keys().cloned().collect();
+        priority_op_ids.sort_unstable();
+        for i in 0..priority_op_ids.len().saturating_sub(1) {
+            let gap = priority_op_ids[i + 1] - priority_op_ids[i];
+            anyhow::ensure!(
+                gap == 1,
+                "Gap in priority op queue: gap={}, priority_op_before_gap={}",
+                gap,
+                priority_op_ids[i]
+            );
+        }
+
         let new_state = ETHState::new(last_ethereum_block, unconfirmed_queue, priority_queue);
         self.set_new_state(new_state);
         Ok(())
@@ -184,7 +195,7 @@ impl<W: EthClient> EthWatch<W> {
             new_block_with_accepted_events.saturating_sub(unprocessed_blocks_amount);
 
         let unconfirmed_queue = self.get_unconfirmed_ops(current_ethereum_block).await?;
-        let priority_queue = self
+        let priority_queue: HashMap<u64, _> = self
             .client
             .get_priority_op_events(
                 BlockNumber::Number(previous_block_with_accepted_events.into()),
@@ -195,6 +206,15 @@ impl<W: EthClient> EthWatch<W> {
             .map(|priority_op| (priority_op.serial_id, priority_op.into()))
             .collect();
 
+        let mut new_priority_op_ids: Vec<_> = priority_queue.keys().cloned().collect();
+        new_priority_op_ids.sort_unstable();
+        vlog::debug!(
+            "Updating eth state: block_range=[{},{}], new_priority_ops={:?}",
+            previous_block_with_accepted_events,
+            new_block_with_accepted_events,
+            new_priority_op_ids
+        );
+
         Ok((unconfirmed_queue, priority_queue))
     }
 

From b088ccc12142901ba0a3736cad59b2d2547e9567 Mon Sep 17 00:00:00 2001
From: deniallugo <deniallugo@gmail.com>
Date: Wed, 14 Jul 2021 17:56:41 +0300
Subject: [PATCH 2/2] Add check about invalid target account

Signed-off-by: deniallugo <deniallugo@gmail.com>
---
 core/lib/state/src/handler/error.rs       | 2 ++
 core/lib/state/src/handler/forced_exit.rs | 8 +++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/core/lib/state/src/handler/error.rs b/core/lib/state/src/handler/error.rs
index 911af012b3..fd2762de99 100644
--- a/core/lib/state/src/handler/error.rs
+++ b/core/lib/state/src/handler/error.rs
@@ -52,6 +52,8 @@ pub enum ForcedExitOpError {
     InvalidTokenId,
     #[error("Target account is not locked; forced exit is forbidden")]
     TargetAccountNotLocked,
+    #[error("Target account is invalid")]
+    InvalidTargetAccount,
     #[error("Nonce mismatch")]
     NonceMismatch,
     #[error("Initiator account: Not enough balance to cover fees")]
diff --git a/core/lib/state/src/handler/forced_exit.rs b/core/lib/state/src/handler/forced_exit.rs
index b27bd4d962..f820441781 100644
--- a/core/lib/state/src/handler/forced_exit.rs
+++ b/core/lib/state/src/handler/forced_exit.rs
@@ -1,6 +1,8 @@
 use std::time::Instant;
 use zksync_crypto::params;
-use zksync_types::{AccountUpdate, AccountUpdates, ForcedExit, ForcedExitOp, PubKeyHash, ZkSyncOp};
+use zksync_types::{
+    AccountUpdate, AccountUpdates, Address, ForcedExit, ForcedExitOp, PubKeyHash, ZkSyncOp,
+};
 use zksync_utils::BigUintSerdeWrapper;
 
 use crate::{
@@ -37,6 +39,10 @@ impl TxHandler<ForcedExit> for ZkSyncState {
             account.pub_key_hash == PubKeyHash::default(),
             ForcedExitOpError::TargetAccountNotLocked
         );
+        invariant!(
+            account.address != Address::default(),
+            ForcedExitOpError::InvalidTargetAccount
+        );
 
         // Obtain the token balance to be withdrawn.
         let account_balance = self