TypeError: ZksyncEnv.execute_code() missing 'simulate' parameter compatibility with anvil-zksync

[dettriva]

Bug Description

Contract deployment works correctly on anvil-zksync, but any subsequent function calls (both view and state-changing functions) fail with TypeError: ZksyncEnv.execute_code() got an unexpected keyword argument 'simulate'. This prevents any post-deployment interaction with contracts on ZKsync networks.

Environment

• Moccasin version: v0.4.2
• anvil-zksync version: 0.6.9
• OS: Ubuntu 22.04 (WSL on Windows 11)
• Network: eravm (anvil-zksync)
• Python: 3.13

Steps to Reproduce

1. Setup: Configure anvil-zksync network in moccasin.toml:

   [networks.eravm]
   url = "http://localhost:8011"
   chain_id = 260
   is_zksync = true

2. Deploy contract:

   mox run deploy --network eravm

   ✅ This works successfully - contract deploys without issues

3. Try to interact with deployed contract:

   mox console --network eravm

   import boa
   contract = boa.load("src/favorites.vy")
   contract.retrieve()  # This fails

4. Error occurs on any function call attempt

Expected Behavior

Contract functions should execute normally after successful deployment, allowing full interaction with deployed contracts.

Actual Behavior

TypeError: ZksyncEnv.execute_code() got an unexpected keyword argument 'simulate'

Full Error Stack Trace

File "/home/daniele/.local/share/uv/tools/moccasin/lib/python3.13/site-packages/boa/contracts/abi/abi_contract.py", line 128, in __call__
  computation = self.contract.env.execute_code(
      to_address=self.contract.address,
  ...<6 lines>...
      contract=self.contract,
  )
TypeError: ZksyncEnv.execute_code() got an unexpected keyword argument 'simulate'

Code Sample

Working deployment script (script/deploy.py):

import boa

def deploy_favorites():
    favorites_contract = boa.load("src/favorites.vy")
    
    # This line fails with the 'simulate' error:
    starting_number: int = favorites_contract.retrieve()
    print(f"The starting number is: {starting_number}")
    
    return favorites_contract

def moccasin_main():
    return deploy_favorites()

Contract (src/favorites.vy):

# pragma version 0.4.3

my_favorite_number: uint256

@deploy
def __init__():
    self.my_favorite_number = 7

@external
@view
def retrieve() -> uint256:
    return self.my_favorite_number

@external
def store(favorite_number: uint256):
    self.my_favorite_number = favorite_number

Successful Deployment Evidence

• Transaction Hash: 0xcc000352d2e39b0fbfe2b07dc8185d347f235f94a15f6e681d34e7ecf0472165
• Contract Address: 0x588758d8a0Ad1162A6294f3C274753137E664aE0
• Gas Used: 682,947 / 1,192,652

Current Workaround

Remove all post-deployment function calls from deployment scripts:

def deploy_favorites():
    favorites_contract = boa.load("src/favorites.vy")
    
    # Comment out function calls to avoid the error
    # starting_number: int = favorites_contract.retrieve()
    # print(f"The starting number is: {starting_number}")
    
    print(f"Contract deployed at: {favorites_contract.address}")
    return favorites_contract

Additional Notes

• The issue affects both boa.load() and favorites.deploy() methods
• All contract function calls fail (view functions, state-changing functions)
• The deployment process itself works perfectly
• Moccasin works correctly with standard anvil (non-ZKsync)
• This appears to be a compatibility issue between Moccasin v0.4.2 and anvil-zksync 0.6.9

Impact

This bug prevents any meaningful development workflow with ZKsync contracts in Moccasin, as developers cannot test or interact with their deployed contracts.

[s3bc40]

pragma version 0.4.3

Hey so you are using the latest vyper so it will have issues for zkvyper.

Moccasin in not the issue but boa ZKSync is sadly. I'll check later to adapt the latest releases. But for now I would suggest to force Vyper to 0.4.1 and run your subsequent lessons in your venv:

uv add vyper==0.4.1

Also adapt your pragmas to avoid running inside the VVM of Vyper.

I'll see what I can do when I have some time!