bug(`anvil`): invalid balance updates for CELO token on Anvil fork

[0xwetzo]

Component

Anvil

Have you ensured that all of these are up to date?

• Foundry
• Foundryup

What version of Foundry are you on?

forge Version: 1.1.0-nightly

What version of Foundryup are you on?

no output

What command(s) is the bug in?

No response

Operating System

macOS (Intel)

Describe the bug

I created a small repo for the code: https://github.com/0xwetzo/Anvil-Celo
The justfile helps to run the code step by step and make changes.

The issue seems to be with balance updates for native tokens like CELO or METIS that are both gas token and ERC20 at the same time.
The balances are not properly updating during the transaction, as seen in the traces, and are incorrect at the end of it too, using cast balance.

The function receives native CELO and calls a mock swap router that will swap ERC20 CELO for USDC, then sends remaining balance to caller as ERC20.

    function test(address router, bytes calldata data) external payable {
        uint256 balance = address(this).balance;

        NATIVE_TOKEN.approve(router, balance);
        
        (bool success, ) = router.call(data);

        require(success);

        uint256 newBalance = NATIVE_TOKEN.balanceOf(address(this));

        NATIVE_TOKEN.transfer(msg.sender, newBalance);
    }

The expected and observed balances are:

# Expected balances (CELO)  Init        Test called     Router called   Final transfer
# Owner                     10,000      9,999           9,999           9.999.5
# Contract                  0           1               0.5             0
# Router                    0           0               0.5             0.5

# Trace balances            Init        Test called     Router called   Final transfer
# Owner                     >= 1        >= 0            >= 0            >= 0.5
# Contract                  0           1               1 (wrong)       0
# Router                    0           0               0.5             0.5

# Cast balances             Init        Test called     Router called   Final transfer
# Owner                     10,000      ?               ?               9,999
# Contract                  0           ?               ?               1 (wrong)
# Router                    0           ?               ?               0 (wrong)

And the traces:

Traces:
  [97908] 0x8198f5d8F8CfFE8f9C413d98a0A55aEB8ab9FbB7::test{value: 1000000000000000000}(0x0355B7B8cb128fA5692729Ab3AAa199C1753f726, 0xfe029156000000000000000000000000471ece3750da237f93b8e339c536989b8978a438000000000000000000000000ceba9300f2b948710d2653dd7b07f33a8b32118c00000000000000000000000000000000000000000000000006f05b59d3b2000000000000000000000000000000000000000000000000000000000000075bcd15)
    ├─ [29958] 0x471EcE3750Da237f93B8E339c536989b8978a438::approve(0x0355B7B8cb128fA5692729Ab3AAa199C1753f726, 1000000000000000000 [1e18])
    │   ├─ [24552] 0xFa77529cD8F0dD86df93CC0d53ed9Bb5Db0ad6D5::approve(0x0355B7B8cb128fA5692729Ab3AAa199C1753f726, 1000000000000000000 [1e18]) [delegatecall]
    │   │   ├─ emit Approval(param0: 0x8198f5d8F8CfFE8f9C413d98a0A55aEB8ab9FbB7, param1: 0x0355B7B8cb128fA5692729Ab3AAa199C1753f726, param2: 1000000000000000000 [1e18])
    │   │   └─ ← [Return] 0x0000000000000000000000000000000000000000000000000000000000000001
    │   └─ ← [Return] 0x0000000000000000000000000000000000000000000000000000000000000001
    ├─ [53790] 0x0355B7B8cb128fA5692729Ab3AAa199C1753f726::swap(0x471EcE3750Da237f93B8E339c536989b8978a438, 0xcebA9300f2b948710d2653dD7B07f33A8B32118C, 500000000000000000 [5e17], 123456789 [1.234e8])
    │   ├─ [7907] 0x471EcE3750Da237f93B8E339c536989b8978a438::transferFrom(0x8198f5d8F8CfFE8f9C413d98a0A55aEB8ab9FbB7, 0x0355B7B8cb128fA5692729Ab3AAa199C1753f726, 500000000000000000 [5e17])
    │   │   ├─ [6995] 0xFa77529cD8F0dD86df93CC0d53ed9Bb5Db0ad6D5::transferFrom(0x8198f5d8F8CfFE8f9C413d98a0A55aEB8ab9FbB7, 0x0355B7B8cb128fA5692729Ab3AAa199C1753f726, 500000000000000000 [5e17]) [delegatecall]
    │   │   │   ├─ [0] 0x00000000000000000000000000000000000000fd::00000000(00000000000000008198f5d8f8cffe8f9c413d98a0a55aeb8ab9fbb70000000000000000000000000355b7b8cb128fa5692729ab3aaa199c1753f72600000000000000000000000000000000000000000000000006f05b59d3b20000)
    │   │   │   │   └─ ← [Stop]
    │   │   │   ├─ emit Transfer(param0: 0x8198f5d8F8CfFE8f9C413d98a0A55aEB8ab9FbB7, param1: 0x0355B7B8cb128fA5692729Ab3AAa199C1753f726, param2: 500000000000000000 [5e17])
    │   │   │   └─ ← [Return] 0x0000000000000000000000000000000000000000000000000000000000000001
    │   │   └─ ← [Return] 0x0000000000000000000000000000000000000000000000000000000000000001
    │   ├─ [40563] 0xcebA9300f2b948710d2653dD7B07f33A8B32118C::transfer(0x8198f5d8F8CfFE8f9C413d98a0A55aEB8ab9FbB7, 123456789 [1.234e8])
    │   │   ├─ [33363] 0xdA06D4e3F59fE2C8ff3077A9D50D5BE5E231BEcD::transfer(0x8198f5d8F8CfFE8f9C413d98a0A55aEB8ab9FbB7, 123456789 [1.234e8]) [delegatecall]
    │   │   │   ├─ emit Transfer(param0: 0x0355B7B8cb128fA5692729Ab3AAa199C1753f726, param1: 0x8198f5d8F8CfFE8f9C413d98a0A55aEB8ab9FbB7, param2: 123456789 [1.234e8])
    │   │   │   └─ ← [Return] 0x0000000000000000000000000000000000000000000000000000000000000001
    │   │   └─ ← [Return] 0x0000000000000000000000000000000000000000000000000000000000000001
    │   └─ ← [Stop]
    ├─ [1423] 0x471EcE3750Da237f93B8E339c536989b8978a438::balanceOf(0x8198f5d8F8CfFE8f9C413d98a0A55aEB8ab9FbB7) [staticcall]
    │   ├─ [523] 0xFa77529cD8F0dD86df93CC0d53ed9Bb5Db0ad6D5::balanceOf(0x8198f5d8F8CfFE8f9C413d98a0A55aEB8ab9FbB7) [delegatecall]
    │   │   └─ ← [Return] 0x0000000000000000000000000000000000000000000000000de0b6b3a7640000
    │   └─ ← [Return] 0x0000000000000000000000000000000000000000000000000de0b6b3a7640000
    ├─ [4299] 0x471EcE3750Da237f93B8E339c536989b8978a438::transfer(0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266, 1000000000000000000 [1e18])
    │   ├─ [3393] 0xFa77529cD8F0dD86df93CC0d53ed9Bb5Db0ad6D5::transfer(0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266, 1000000000000000000 [1e18]) [delegatecall]
    │   │   ├─ [0] 0x00000000000000000000000000000000000000fd::00000000(00000000000000008198f5d8f8cffe8f9c413d98a0a55aeb8ab9fbb7000000000000000000000000f39fd6e51aad88f6f4ce6ab8827279cfffb922660000000000000000000000000000000000000000000000000de0b6b3a7640000)
    │   │   │   └─ ← [Stop]
    │   │   ├─ emit Transfer(param0: 0x8198f5d8F8CfFE8f9C413d98a0A55aEB8ab9FbB7, param1: 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266, param2: 1000000000000000000 [1e18])
    │   │   └─ ← [Return] 0x0000000000000000000000000000000000000000000000000000000000000001
    │   └─ ← [Return] 0x0000000000000000000000000000000000000000000000000000000000000001
    └─ ← [Stop]


Transaction successfully executed.

I presume that the bug comes from Anvil and the special management of the hybrid token CELO.

[grandizzy]

@0xwetzo do you know which evm version is celo compatible? is that cancun (which is default on foundry) or different?

[0xwetzo]

@0xwetzo do you know which evm version is celo compatible? is that cancun (which is default on foundry) or different?

I would say Cancun.
Here they do not give any special indication when using Foundry: https://docs.celo.org/developer/deploy/foundry
And I already deployed contracts from Foundry without needing to specify the version with --evm-version.