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Debugging#

Using Python debugger#

wake test supports entering pdb, the Python debugger, when an error occurs. Wake uses an enhanced version of the Python debugger, ipdb, which provides a more user-friendly interface.

It is also possible to enter the debugger manually by inserting a breakpoint() statement in the code.

from wake.testing import *


@chain.connect()
def test_breakpoint():
    breakpoint()
    block = chain.blocks[0]

Info

breakpoint() is not currently supported when running wake test in multiprocessing mode (with the -P option set)

Inside ipdb, any expression can be evaluated by typing it and pressing Enter. This can be used to get the value of a variable, to call a function, including contract functions, or even to deploy a new contract.

Useful commands:

  • h or help: show help
  • c or continue: continue execution
  • n or next: step over the next line
  • l or list: show the current line and a few lines around it
  • q or quit: quit the debugger
  • up or down: move up or down the call stack

Call traces#

Every transaction object has a call_trace property that visualizes the call stack of the transaction. It can be used to debug failing transactions.

External contracts in forking mode

When using forking mode (see connect keyword arguments), already present contracts are printed as unknown contracts in call traces. To show contract and function names, configure your API key for a given chain explorer.

from wake.testing import *
from pytypes.contracts.Counter import Counter
from pytypes.contracts.Gateway import Gateway


@chain.connect()
def test_call_trace():
    gateway = Gateway.deploy()
    counter = Counter.deploy()
    counter.addToWhitelist(gateway)

    tx = gateway.execute(
        counter,
        Abi.encode_call(counter.decrement, []),
        confirmations=0,
    )
    print(tx.call_trace)

    tx = gateway.execute(
        counter,
        Abi.encode_call(counter.increment, []),
    )
    print(tx.call_trace)
wake test Gateway.execute(0xe7f1725e7734ce288f8367e1bb143e90bb3f0512, b'+\xae\xce\xb7') ✗ ➞ Error('call failed') └── Counter.decrement() ✗ ➞ Panic(<PanicCodeEnum.UNDERFLOW_OVERFLOW:17>) Gateway.execute(0xe7f1725e7734ce288f8367e1bb143e90bb3f0512, b'\xd0\x9d\xe0\x8a') ✓ └── Counter.increment() ✓ └── console.log('Incremented count to', 1) ✓[STATICCALL]

Info

Internal calls are not currently visualized in call traces.

Console logs#

Using the console.sol library from Hardhat may be the easiest way to debug a contract. Logs can be accessed through the console_logs property of a transaction object. Console logs are available even for failed transactions.

from wake.testing import *
from pytypes.contracts.Counter import Counter


@chain.connect()
def test_console_logs():
    chain.tx_callback = lambda tx: print(tx.console_logs)

    counter = Counter.deploy()
    counter.increment()
    counter.setCount(42)

Wake-integrated console.sol

Wake integrates the console.sol library implementing the same functionalities as Hardhat's console.sol. It can serve as a drop-in replacement in case that the tested project is not using Hardhat.

import "wake/console.sol";

contract MyContract {
    function myFunction() public view {
        console.log("Hello world!");
    }
}