feat(eth_sender): Set fusaka upgrade timestamp (#4571)

## What ❔

Use upgrade timestamp as well as block for switching to fusaka blobs

## Why ❔

Unfortunately ETH foundation doesn't provide the exact block for fusaka,
but they have the exact timestamp. So it was decided to use this
timestamp and half an hour before and after this as a safety margin

https://blog.ethereum.org/2025/11/06/fusaka-mainnet-announcement#fusaka-activation

## Is this a breaking change?
- [ ] Yes
- [ ] No

## Operational changes
<!-- Any config changes? Any new flags? Any changes to any scripts? -->
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## Checklist

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

Signed-off-by: Danil <[email protected]>

Author: Deniallugo

core/lib/config/src/configs/eth_sender.rs

@@ -56,6 +56,7 @@ impl EthConfig {
                 force_use_validator_timelock: false,
                 fusaka_upgrade_block: Some(0),
                 fusaka_upgrade_safety_margin: 0,
+                fusaka_upgrade_timestamp: Some(1),
             },
             gas_adjuster: GasAdjusterConfig {
                 default_priority_fee_per_gas: 1000000000,
@@ -181,8 +182,13 @@ pub struct SenderConfig {
     pub force_use_validator_timelock: bool,
     /// Use fusaka blob tx format if  the block has passed.
     pub fusaka_upgrade_block: Option<u64>,
-    #[config(default_t = 100)]
+    /// Half an hour safety margin
+    #[config(default_t = 1800)]
     pub fusaka_upgrade_safety_margin: u64,
+    /// Use fusaka blob tx format if  the timestamp has passed. Default is mainnet upgrade.
+    /// Use this value if block is not set
+    #[config(default_t = Some(1764798551))]
+    pub fusaka_upgrade_timestamp: Option<u64>,
 }
 
 /// We send precommit if l2_blocks_to_aggregate OR deadline_sec passed since last precommit or beginning of batch.
@@ -309,6 +315,7 @@ mod tests {
                 force_use_validator_timelock: false,
                 fusaka_upgrade_safety_margin: 100,
                 fusaka_upgrade_block: Some(33582142),
+                fusaka_upgrade_timestamp: Some(1),
             },
             gas_adjuster: GasAdjusterConfig {
                 default_priority_fee_per_gas: 20000000000,
@@ -376,6 +383,7 @@ mod tests {
             ETH_SENDER_SENDER_USE_FUSAKA_BLOB_FORMAT="true"
             ETH_SENDER_SENDER_USE_FUSAKA_BLOB_FORMAT="true"
             ETH_SENDER_SENDER_FUSAKA_UPGRADE_BLOCK="33582142"
+            ETH_SENDER_SENDER_FUSAKA_UPGRADE_TIMESTAMP="1"
             ETH_SENDER_SENDER_FUSAKA_UPGRADE_SAFETY_MARGIN="100"
 
         "#;
@@ -416,6 +424,7 @@ mod tests {
             force_use_validator_timelock: false
             fusaka_upgrade_safety_margin: 100
             fusaka_upgrade_block: 33582142
+            fusaka_upgrade_timestamp: 1
             precommit_params:
               l2_blocks_to_aggregate: 1
               deadline: 1 sec
@@ -475,6 +484,7 @@ mod tests {
             force_use_validator_timelock: false
             fusaka_upgrade_safety_margin: 100
             fusaka_upgrade_block: 33582142
+            fusaka_upgrade_timestamp: 1
             precommit_params:
               l2_blocks_to_aggregate: 1
               deadline: 1 sec

core/lib/eth_client/src/lib.rs

@@ -334,4 +334,8 @@ impl dyn BoundEthInterface {
     pub async fn block_number(&self) -> EnrichedClientResult<U64> {
         self.as_ref().block_number().await
     }
+
+    pub async fn block(&self, block_id: BlockId) -> EnrichedClientResult<Option<Block<H256>>> {
+        self.as_ref().block(block_id).await
+    }
 }

core/node/eth_sender/src/eth_tx_aggregator.rs

@@ -33,7 +33,7 @@ use zksync_types::{
     pubdata_da::PubdataSendingMode,
     server_notification::GatewayMigrationState,
     settlement::SettlementLayer,
-    web3::{contract::Error as Web3ContractError, CallRequest},
+    web3::{contract::Error as Web3ContractError, BlockId, BlockNumber, CallRequest},
     Address, L1BatchNumber, L2ChainId, ProtocolVersionId, SLChainId, H256, U256,
 };
 
@@ -204,17 +204,56 @@ impl EthTxAggregator {
         if self.config.fusaka_upgrade_block == Some(0) {
             return Ok(EthereumUpgradeState::Finished);
         }
-        let Some(fusaka_upgrade_block) = self.config.fusaka_upgrade_block else {
+
+        if self.config.fusaka_upgrade_timestamp.is_none()
+            && self.config.fusaka_upgrade_block.is_none()
+        {
             return Ok(EthereumUpgradeState::NotStarted);
-        };
+        }
 
-        let current_block = self.eth_client.block_number().await?.as_u64();
-        if current_block - self.config.fusaka_upgrade_safety_margin < fusaka_upgrade_block {
-            Ok(EthereumUpgradeState::NotStarted)
-        } else if current_block < fusaka_upgrade_block {
-            Ok(EthereumUpgradeState::Pending)
-        } else {
-            Ok(EthereumUpgradeState::Finished)
+        let current_block = self
+            .eth_client
+            .block(BlockId::Number(BlockNumber::Latest))
+            .await?
+            .expect("Latest block not found");
+
+        // Prioritize using the block number for the upgrade if both are set
+        // Timestamp is set with default, so block number takes precedence
+        match (
+            self.config.fusaka_upgrade_block,
+            self.config.fusaka_upgrade_timestamp,
+        ) {
+            (Some(fusaka_upgrade_block), _) => {
+                if current_block.number.unwrap().as_u64() - self.config.fusaka_upgrade_safety_margin
+                    < fusaka_upgrade_block
+                {
+                    Ok(EthereumUpgradeState::NotStarted)
+                } else if current_block.number.unwrap().as_u64()
+                    + self.config.fusaka_upgrade_safety_margin
+                    >= fusaka_upgrade_block
+                {
+                    Ok(EthereumUpgradeState::Finished)
+                } else {
+                    Ok(EthereumUpgradeState::Pending)
+                }
+            }
+            (_, Some(fusaka_upgrade_timestamp)) => {
+                let current_timestamp = current_block.timestamp.as_u64();
+                if current_timestamp
+                    < fusaka_upgrade_timestamp - self.config.fusaka_upgrade_safety_margin
+                {
+                    Ok(EthereumUpgradeState::NotStarted)
+                } else if current_timestamp + self.config.fusaka_upgrade_safety_margin
+                    >= fusaka_upgrade_timestamp
+                {
+                    Ok(EthereumUpgradeState::Finished)
+                } else {
+                    Ok(EthereumUpgradeState::Pending)
+                }
+            }
+            // All the values has already been checked this case is rather unreachable.
+            // But for safety reasons, it's better to not panic if it's not necessary
+            (_, _) => Ok(EthereumUpgradeState::NotStarted),
         }
     }