feat(spec-specs): CREATE failure refunds account state gas to reservoir

Author: spencer-tb

src/ethereum/forks/amsterdam/vm/instructions/system.py

@@ -86,11 +86,15 @@ def generic_create(
     if memory_size > U256(MAX_INIT_CODE_SIZE):
         raise OutOfGasError
 
-    # Charge state gas for account creation after initcode validation
+    # Charge state gas for account creation (pay-before-execute).
+    # Refunded to the reservoir on any failure path below.
     cost_per_state_byte = state_gas_per_byte(
         evm.message.block_env.block_gas_limit
     )
-    charge_state_gas(evm, STATE_BYTES_PER_NEW_ACCOUNT * cost_per_state_byte)
+    create_account_state_gas = (
+        STATE_BYTES_PER_NEW_ACCOUNT * cost_per_state_byte
+    )
+    charge_state_gas(evm, create_account_state_gas)
 
     tx_state = evm.message.tx_env.state
 
@@ -117,6 +121,9 @@ def generic_create(
     ):
         evm.gas_left += create_message_gas
         evm.state_gas_left += create_message_state_gas_reservoir
+        # No account created — refund state gas to reservoir.
+        evm.state_gas_left += create_account_state_gas
+        evm.state_gas_used -= create_account_state_gas
         push(evm.stack, U256(0))
         return
 
@@ -128,6 +135,9 @@ def generic_create(
         increment_nonce(tx_state, evm.message.current_target)
         evm.regular_gas_used += create_message_gas
         evm.state_gas_left += create_message_state_gas_reservoir
+        # Address collision — no account created, refund state gas.
+        evm.state_gas_left += create_account_state_gas
+        evm.state_gas_used -= create_account_state_gas
         push(evm.stack, U256(0))
         return
 
@@ -157,6 +167,9 @@ def generic_create(
 
     if child_evm.error:
         incorporate_child_on_error(evm, child_evm)
+        # No account created, refund parent's CREATE state gas.
+        evm.state_gas_left += create_account_state_gas
+        evm.state_gas_used -= create_account_state_gas
         evm.return_data = child_evm.output
         push(evm.stack, U256(0))
     else: