From 71481d98555028a22d3b3ee355d6c989cdd88f86 Mon Sep 17 00:00:00 2001
From: Vladimir Motylenko <me@vldm.cc>
Date: Tue, 5 Oct 2021 13:53:04 +0300
Subject: [PATCH] fix(evm): Fix creating of empty block on reset.

---
 evm-utils/evm-state/src/executor.rs                   | 11 +++++++++--
 .../programs/evm_loader/src/precompiles/builtins.rs   |  2 +-
 evm-utils/programs/evm_loader/src/processor.rs        |  5 ++++-
 sdk/src/feature_set.rs                                |  5 +++++
 4 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/evm-utils/evm-state/src/executor.rs b/evm-utils/evm-state/src/executor.rs
index 90a030bff7..f9e5ed7e42 100644
--- a/evm-utils/evm-state/src/executor.rs
+++ b/evm-utils/evm-state/src/executor.rs
@@ -443,8 +443,15 @@ impl Executor {
     }
 
     /// After "swap from evm" transaction EVM_MINT_ADDRESS will cleanup. Using this method.
-    pub fn reset_balance(&mut self, balance: H160) {
-        self.with_executor(|_, _, _, _| None, |e| e.state_mut().reset_balance(balance));
+    pub fn reset_balance(&mut self, swap_addr: H160, ignore_reset_on_cleared: bool) {
+        self.with_executor(
+            |_, _, _, _| None,
+            |e| {
+                if !ignore_reset_on_cleared || e.state().basic(swap_addr).balance != U256::zero() {
+                    e.state_mut().reset_balance(swap_addr)
+                }
+            },
+        );
     }
 
     //  /// Burn some tokens on address:
diff --git a/evm-utils/programs/evm_loader/src/precompiles/builtins.rs b/evm-utils/programs/evm_loader/src/precompiles/builtins.rs
index 0a167d8e25..3e0dfa2978 100644
--- a/evm-utils/programs/evm_loader/src/precompiles/builtins.rs
+++ b/evm-utils/programs/evm_loader/src/precompiles/builtins.rs
@@ -95,7 +95,7 @@ where
 //
 // NativeContracts declaration below
 //
-
+// 0x56454c41532d434841494e000000000053574150 for better search
 // TODO: Implement some procedural macro to render this in more
 pub static ETH_TO_VLX_ADDR: Lazy<H160> = Lazy::new(|| {
     H160::from_str(concat!(
diff --git a/evm-utils/programs/evm_loader/src/processor.rs b/evm-utils/programs/evm_loader/src/processor.rs
index 1903303a6c..25acbaaf91 100644
--- a/evm-utils/programs/evm_loader/src/processor.rs
+++ b/evm-utils/programs/evm_loader/src/processor.rs
@@ -48,6 +48,9 @@ impl EvmProcessor {
             .is_feature_active(&solana_sdk::feature_set::velas::evm_new_error_handling::id());
         let unsigned_tx_fix = invoke_context
             .is_feature_active(&solana_sdk::feature_set::velas::unsigned_tx_fix::id());
+        let ignore_reset_on_cleared = invoke_context
+            .is_feature_active(&solana_sdk::feature_set::velas::ignore_reset_on_cleared::id());
+
         if cross_execution && !cross_execution_enabled {
             ic_msg!(invoke_context, "Cross-Program evm execution not enabled.");
             return Err(EvmError::CrossExecutionNotEnabled.into());
@@ -114,7 +117,7 @@ impl EvmProcessor {
         };
 
         if register_swap_tx_in_evm {
-            executor.reset_balance(*precompiles::ETH_TO_VLX_ADDR)
+            executor.reset_balance(*precompiles::ETH_TO_VLX_ADDR, ignore_reset_on_cleared)
         }
 
         // When old error handling, manually convert EvmError to InstructionError
diff --git a/sdk/src/feature_set.rs b/sdk/src/feature_set.rs
index f6ff1a4c10..a37db9b4f4 100644
--- a/sdk/src/feature_set.rs
+++ b/sdk/src/feature_set.rs
@@ -169,6 +169,10 @@ pub mod velas {
     pub mod unsigned_tx_fix {
         solana_sdk::declare_id!("HfCMpyxjAmu7sPtRdnqdrTf3zDpkErKugzYPnKs4vhat");
     }
+
+    pub mod ignore_reset_on_cleared {
+        solana_sdk::declare_id!("HC6ZH7Dx92Q5dwVLYAaK3SPNCDc1L7Wq41Zuc7FU1mR1");
+    }
 }
 lazy_static! {
     /// Map of feature identifiers to user-visible description
@@ -218,6 +222,7 @@ lazy_static! {
             (velas::native_swap_in_evm_history::id(), "Native swap in evm history."),
             (velas::evm_new_error_handling::id(), "EVM new error handling."),
             (velas::unsigned_tx_fix::id(), "Authorized transaction hash fixed."),
+            (velas::ignore_reset_on_cleared::id(), "Don't reset evm_swap address balance, when it already swapped, to avoid empty blocks."),
             /*************** ADD NEW FEATURES HERE ***************/
         ]
     ).collect();