Reset gas refund counter in ExecutionState

CHANGELOG.md

@@ -5,6 +5,12 @@ Documentation of all notable changes to the **evmone** project.
 The format is based on [Keep a Changelog],
 and this project adheres to [Semantic Versioning].
 
+## [0.9.1] — unreleased
+
+### Fixed
+
+- Resetting gas refund counter when execution state is reused. 
+  [#504](https://github.com/ethereum/evmone/pull/504)
 
 ## [0.9.0] — 2022-08-30
 
@@ -347,6 +353,7 @@ It delivers fully-compatible and high-speed EVM implementation.
 - The [intx 0.2.0](https://github.com/chfast/intx/releases/tag/v0.2.0) library is used for 256-bit precision arithmetic. 
 
 
+[0.9.1]: https://github.com/ethereum/evmone/compare/v0.9.0..release/0.9
 [0.9.0]: https://github.com/ethereum/evmone/releases/tag/v0.9.0
 [0.8.2]: https://github.com/ethereum/evmone/releases/tag/v0.8.2
 [0.8.1]: https://github.com/ethereum/evmone/releases/tag/v0.8.1

lib/evmone/execution_state.hpp

@@ -183,6 +183,7 @@ class ExecutionState
         bytes_view _code) noexcept
     {
         gas_left = message.gas;
+        gas_refund = 0;
         memory.clear();
         msg = &message;
         host = {host_interface, host_ctx};

test/unittests/execution_state_test.cpp

@@ -84,6 +84,7 @@ TEST(execution_state, reset_advanced)
 
     evmone::advanced::AdvancedExecutionState st;
     st.gas_left = 1;
+    st.gas_refund = 2;
     st.stack.push({});
     st.memory.grow(64);
     st.msg = &msg;
@@ -97,6 +98,7 @@ TEST(execution_state, reset_advanced)
     st.analysis.advanced = &analysis;
 
     EXPECT_EQ(st.gas_left, 1);
+    EXPECT_EQ(st.gas_refund, 2);
     EXPECT_EQ(st.stack.size(), 1);
     EXPECT_EQ(st.memory.size(), 64);
     EXPECT_EQ(st.msg, &msg);
@@ -121,6 +123,7 @@ TEST(execution_state, reset_advanced)
         // TODO: We are not able to test HostContext with current API. It may require an execution
         //       test.
         EXPECT_EQ(st.gas_left, 13);
+        EXPECT_EQ(st.gas_refund, 0);
         EXPECT_EQ(st.stack.size(), 0);
         EXPECT_EQ(st.memory.size(), 0);
         EXPECT_EQ(st.msg, &msg2);