From e1817435882a8514d37bb71193c5d9097326467c Mon Sep 17 00:00:00 2001
From: Oba <obatirou@gmail.com>
Date: Thu, 5 Sep 2024 19:06:51 +0200
Subject: [PATCH] fix: call gas refund only if success (#1395)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

<!--- Please provide a general summary of your changes in the title
above -->

<!-- Give an estimate of the time you spent on this PR in terms of work
days.
Did you spend 0.5 days on this PR or rather 2 days?  -->

Time spent on this PR:

## Pull request type

<!-- Please try to limit your pull request to one type,
submit multiple pull requests if needed. -->

Please check the type of change your PR introduces:

- [x] Bugfix
- [ ] Feature
- [ ] Code style update (formatting, renaming)
- [ ] Refactoring (no functional changes, no api changes)
- [ ] Build related changes
- [ ] Documentation content changes
- [ ] Other (please describe):

## What is the current behavior?

<!-- Please describe the current behavior that you are modifying,
or link to a relevant issue. -->

Resolves #1389

## What is the new behavior?

<!-- Please describe the behavior or changes that are being added by
this PR. -->

No refunds are applied if the call reverted

<!-- Reviewable:start -->
- - -
This change is [<img src="https://reviewable.io/review_button.svg"
height="34" align="absmiddle"
alt="Reviewable"/>](https://reviewable.io/reviews/kkrt-labs/kakarot/1395)
<!-- Reviewable:end -->
---
 src/kakarot/instructions/system_operations.cairo | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/kakarot/instructions/system_operations.cairo b/src/kakarot/instructions/system_operations.cairo
index 0bbe8e7ad..73dd31373 100644
--- a/src/kakarot/instructions/system_operations.cairo
+++ b/src/kakarot/instructions/system_operations.cairo
@@ -1032,6 +1032,12 @@ namespace CallHelper {
         ) * evm.return_data_len;
         Memory.store_n(actual_output_size, evm.return_data, ret_offset.low);
 
+        if (evm.reverted != FALSE) {
+            tempvar gas_refund = evm.message.parent.evm.gas_refund;
+        } else {
+            tempvar gas_refund = evm.message.parent.evm.gas_refund + evm.gas_refund;
+        }
+
         tempvar evm = new model.EVM(
             message=message,
             return_data_len=evm.return_data_len,
@@ -1039,7 +1045,7 @@ namespace CallHelper {
             program_counter=evm.message.parent.evm.program_counter + 1,
             stopped=evm.message.parent.evm.stopped,
             gas_left=evm.message.parent.evm.gas_left + evm.gas_left,
-            gas_refund=evm.message.parent.evm.gas_refund + evm.gas_refund,
+            gas_refund=gas_refund,
             reverted=evm.message.parent.evm.reverted,
         );