From 86db9ff6aed4017b0914ff6795295c45246282bf Mon Sep 17 00:00:00 2001
From: perekopskiy <53865202+perekopskiy@users.noreply.github.com>
Date: Tue, 21 Jan 2025 14:34:40 +0200
Subject: [PATCH] fix(api): use scaled version of batch fee input in
 `get_batch_fee_input_impl` (#3507)
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## What ❔

- Use scaled version of batch fee input in get_batch_fee_input_impl
- Improve adjust_pubdata_price_for_tx so it assumes optimistic scenario

## Why ❔

Scaled fee input should be used for every user-facing API method

## Checklist

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

- [ ] 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`.
---
 core/lib/multivm/src/utils/mod.rs               | 14 +++++++++-----
 core/node/api_server/src/web3/namespaces/zks.rs |  4 +---
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/core/lib/multivm/src/utils/mod.rs b/core/lib/multivm/src/utils/mod.rs
index 7bb907efc9b8..825874747682 100644
--- a/core/lib/multivm/src/utils/mod.rs
+++ b/core/lib/multivm/src/utils/mod.rs
@@ -113,13 +113,13 @@ pub fn adjust_pubdata_price_for_tx(
 ) -> BatchFeeInput {
     // If no max base fee was provided, we just use the maximal one for convenience.
     let max_base_fee = max_base_fee.unwrap_or(U256::MAX);
-    let desired_gas_per_pubdata =
+    let bounded_tx_gas_per_pubdata_limit =
         tx_gas_per_pubdata_limit.min(get_max_gas_per_pubdata_byte(vm_version).into());
 
     let (current_base_fee, current_gas_per_pubdata) =
         derive_base_fee_and_gas_per_pubdata(batch_fee_input, vm_version);
 
-    if U256::from(current_gas_per_pubdata) <= desired_gas_per_pubdata
+    if U256::from(current_gas_per_pubdata) <= bounded_tx_gas_per_pubdata_limit
         && U256::from(current_base_fee) <= max_base_fee
     {
         // gas per pubdata is already smaller than or equal to `tx_gas_per_pubdata_limit`.
@@ -138,8 +138,9 @@ pub fn adjust_pubdata_price_for_tx(
             // `gasPerPubdata = ceil(17 * l1gasprice / fair_l2_gas_price)`
             // `gasPerPubdata <= 17 * l1gasprice / fair_l2_gas_price + 1`
             // `fair_l2_gas_price(gasPerPubdata - 1) / 17 <= l1gasprice`
-            let new_l1_gas_price =
-                fair_l2_gas_price * (desired_gas_per_pubdata - U256::from(1u32)) / U256::from(17);
+            let new_l1_gas_price = fair_l2_gas_price
+                * bounded_tx_gas_per_pubdata_limit.saturating_sub(U256::from(1u32))
+                / U256::from(17);
 
             BatchFeeInput::L1Pegged(L1PeggedBatchFeeModelInput {
                 l1_gas_price: new_l1_gas_price.as_u64(),
@@ -154,11 +155,14 @@ pub fn adjust_pubdata_price_for_tx(
                 current_l2_fair_gas_price
             };
 
+            // We want to adjust gas per pubdata to be min(bounded_tx_gas_per_pubdata_limit, current_gas_per_pubdata).
+            let desired_gas_per_pubdata =
+                bounded_tx_gas_per_pubdata_limit.min(U256::from(current_gas_per_pubdata));
             // `gasPerPubdata = ceil(fair_pubdata_price / fair_l2_gas_price)`
             // `gasPerPubdata <= fair_pubdata_price / fair_l2_gas_price + 1`
             // `fair_l2_gas_price(gasPerPubdata - 1) <= fair_pubdata_price`
             let new_fair_pubdata_price =
-                fair_l2_gas_price * (desired_gas_per_pubdata - U256::from(1u32));
+                fair_l2_gas_price * desired_gas_per_pubdata.saturating_sub(U256::from(1u32));
 
             BatchFeeInput::PubdataIndependent(PubdataIndependentBatchFeeModelInput {
                 fair_pubdata_price: new_fair_pubdata_price.as_u64(),
diff --git a/core/node/api_server/src/web3/namespaces/zks.rs b/core/node/api_server/src/web3/namespaces/zks.rs
index b272f7c443e9..9f7c5662a631 100644
--- a/core/node/api_server/src/web3/namespaces/zks.rs
+++ b/core/node/api_server/src/web3/namespaces/zks.rs
@@ -677,9 +677,7 @@ impl ZksNamespace {
         Ok(self
             .state
             .tx_sender
-            .0
-            .batch_fee_input_provider
-            .get_batch_fee_input()
+            .scaled_batch_fee_input()
             .await?
             .into_pubdata_independent())
     }