new(tests): Explicit test for EXTDELEGATECALL value cost (#911)

Author: pdobacz

tests/osaka/eip7692_eof_v1/eip7069_extcall/test_gas.py

@@ -140,3 +140,47 @@ def test_ext_calls_gas(
         cold_gas=cold_gas + cost_memory_bytes(mem_expansion_bytes, 0),
         warm_gas=warm_gas + cost_memory_bytes(mem_expansion_bytes, 0),
     )
+
+
+@pytest.mark.parametrize("opcode", [Op.EXTCALL, Op.EXTDELEGATECALL, Op.EXTSTATICCALL])
+@pytest.mark.parametrize("value", [0, 1])
+def test_transfer_gas_is_cleared(
+    state_test: StateTestFiller,
+    pre: Alloc,
+    state_env: Environment,
+    opcode: Op,
+    value: int,
+):
+    """
+    Test that EXT*CALL call doesn't charge for value transfer, even if the outer call
+    transfered value.
+
+    NOTE: This is particularly possible for EXTDELEGATECALL, which carries over the value sent
+    in the outer call, however, we extend the test to all 3 EXT*CALL opcodes for good measure.
+    """
+    noop_callee_address = pre.deploy_contract(Container.Code(Op.STOP))
+
+    extdelegatecall_contract_address = pre.deploy_contract(
+        Container.Code(opcode(address=noop_callee_address) + Op.STOP)
+    )
+
+    push_gas = (4 if opcode == Op.EXTCALL else 3) * 3
+
+    gas_test(
+        state_test,
+        state_env,
+        pre,
+        setup_code=Op.PUSH1(value) + Op.PUSH0 * 2 + Op.PUSH20(extdelegatecall_contract_address),
+        subject_code=Op.EXTCALL,
+        subject_balance=5 * value,
+        tear_down_code=Op.STOP,
+        # NOTE: CALL_WITH_VALUE_GAS is charged only once on the outer EXTCALL, while the base
+        # call gas - twice.
+        cold_gas=2 * COLD_ACCOUNT_ACCESS_GAS
+        + (CALL_WITH_VALUE_GAS if value > 0 else 0)
+        + push_gas,
+        warm_gas=2 * WARM_ACCOUNT_ACCESS_GAS
+        + (CALL_WITH_VALUE_GAS if value > 0 else 0)
+        + push_gas,
+        out_of_gas_testing=False,
+    )

tests/osaka/eip7692_eof_v1/gas_test.py

@@ -38,6 +38,7 @@ def gas_test(
     subject_address: Address | None = None,
     subject_balance: int = 0,
     oog_difference: int = 1,
+    out_of_gas_testing: bool = True,
 ):
     """
     Creates a State Test to check the gas cost of a sequence of EOF code.
@@ -104,27 +105,33 @@ def gas_test(
             + (Op.DUP3 + Op.SWAP1 + Op.SUB + Op.PUSH2(slot_warm_gas) + Op.SSTORE)
             # store cold gas: DUP2 is the gas of the baseline gas run
             + (Op.DUP2 + Op.SWAP1 + Op.SUB + Op.PUSH2(slot_cold_gas) + Op.SSTORE)
-            # oog gas run:
-            # - DUP7 is the gas of the baseline gas run, after other CALL args were pushed
-            # - subtract the gas charged by the harness
-            # - add warm gas charged by the subject
-            # - subtract `oog_difference` to cause OOG exception (1 by default)
-            + Op.SSTORE(
-                slot_oog_call_result,
-                Op.CALL(
-                    gas=Op.ADD(warm_gas - gas_single_gas_run - oog_difference, Op.DUP7),
-                    address=address_subject,
-                ),
-            )
-            # sanity gas run: not subtracting 1 to see if enough gas makes the call succeed
-            + Op.SSTORE(
-                slot_sanity_call_result,
-                Op.CALL(
-                    gas=Op.ADD(warm_gas - gas_single_gas_run, Op.DUP7),
-                    address=address_subject,
-                ),
+            + (
+                (
+                    # do an oog gas run, unless skipped with `out_of_gas_testing=False`:
+                    # - DUP7 is the gas of the baseline gas run, after other CALL args were pushed
+                    # - subtract the gas charged by the harness
+                    # - add warm gas charged by the subject
+                    # - subtract `oog_difference` to cause OOG exception (1 by default)
+                    Op.SSTORE(
+                        slot_oog_call_result,
+                        Op.CALL(
+                            gas=Op.ADD(warm_gas - gas_single_gas_run - oog_difference, Op.DUP7),
+                            address=address_subject,
+                        ),
+                    )
+                    # sanity gas run: not subtracting 1 to see if enough gas makes the call succeed
+                    + Op.SSTORE(
+                        slot_sanity_call_result,
+                        Op.CALL(
+                            gas=Op.ADD(warm_gas - gas_single_gas_run, Op.DUP7),
+                            address=address_subject,
+                        ),
+                    )
+                    + Op.STOP
+                )
+                if out_of_gas_testing
+                else Op.STOP
             )
-            + Op.STOP
         ),
         evm_code_type=EVMCodeType.LEGACY,  # Needs to be legacy to use GAS opcode
     )
@@ -134,12 +141,14 @@ def gas_test(
             storage={
                 slot_warm_gas: warm_gas,
                 slot_cold_gas: cold_gas,
-                slot_oog_call_result: LEGACY_CALL_FAILURE,
-                slot_sanity_call_result: LEGACY_CALL_SUCCESS,
             },
         ),
     }
 
+    if out_of_gas_testing:
+        post[address_legacy_harness].storage[slot_oog_call_result] = LEGACY_CALL_FAILURE
+        post[address_legacy_harness].storage[slot_sanity_call_result] = LEGACY_CALL_SUCCESS
+
     tx = Transaction(to=address_legacy_harness, gas_limit=env.gas_limit, sender=sender)
 
     state_test(env=env, pre=pre, tx=tx, post=post)