Foundry Book

forge debug

NAME

forge-debug - Debug a single smart contract as a script.

SYNOPSIS

forge debug [options] path [args...]

DESCRIPTION

Debugs a single smart contract located in the source file (path) as a script.

If multiple contracts are in the specified source file, you must pass --target-contract to specify what contract you want to run.

Calls

After the script is deployed to the internal EVM a call is made to a function with the signature setUp(), if present.

By default, the script is assumed to be contained in a function with the signature run(). If you wish to run a different function, pass --sig <SIGNATURE>.

The signature can be a fragment (<function name>(<types>)), or raw calldata.

If you pass a fragment, and the function has parameters, you can add the call parameters to the end of the command (args).

Forking

It is possible to run the script in a forked environment by passing --fork-url <URL>.

When the script is running in a forked environment, you can access all the state of the forked chain as you would if you had deployed the script. Cheatcodes are still available.

You can also specify a block number to fork from by passing --fork-block-number <BLOCK>. When forking from a specific block, the chain data is cached to ~/.foundry/cache. If you do not want to cache the chain data, pass --no-storage-caching.

Debugging

It is possible to run the script in an interactive debugger. To start the debugger, pass --debug.

More information on the debugger can be found in the debugger chapter.

OPTIONS

Debug Options

--target-contract contract_name
The name of the contract you want to run

-s signature
--sig signature
The signature of the function you want to call in the contract, or raw calldata. Default: run()

--debug
Open the script in the debugger.

EVM Options

-f url
--fork-url url
Fetch state over a remote endpoint instead of starting from an empty state.

If you want to fetch state from a specific block number, see --fork-block-number.

--fork-block-number block
Fetch state from a specific block number over a remote endpoint. See --fork-url.

--no-storage-caching
Explicitly disables the use of RPC caching.

All storage slots are read entirely from the endpoint. See --fork-url.

-v
--verbosity
Verbosity of the EVM.

Pass multiple times to increase the verbosity (e.g. -v, -vv, -vvv).

    Verbosity levels:
    - 2: Print logs for all tests
    - 3: Print execution traces for failing tests
    - 4: Print execution traces for all tests, and setup traces for failing tests
    - 5: Print execution and setup traces for all tests

--sender address
The address which will be executing tests

--initial-balance balance
The initial balance of deployed contracts

--ffi
Enables the FFI cheatcode

Executor Options

--base-fee <FEE>
--block-base-fee-per-gas <FEE>
The base fee in a block (in wei)

--block-coinbase address
The coinbase of the block

--block-difficulty difficulty
The block difficulty

--block-gas-limit gas_limit
The block gas limit

--block-number block
The block number

--block-timestamp timestamp
The timestamp of the block (in seconds)

--chain-id chain_id
The chain ID

--gas-limit gas_limit
The block gas limit

--gas-price gas_price
The gas price (in wei)

--tx-origin address
The transaction origin

Cache Options

--force
Clear the cache and artifacts folder and recompile.

Linker Options

--libraries libraries
Set pre-linked libraries.

The parameter must be in the format <remapped path to lib>:<library name>:<address>, e.g. src/Contract.sol:Library:0x....

Can also be set in your configuration file as libraries = ["<path>:<lib name>:<address>"].

Compiler Options

--optimize
Active the Solidity optimizer.

--optimizer-runs runs
The number of optimizer runs.

--via-ir
Use the Yul intermediate representation compilation pipeline.

--revert-strings
How to treat revert and require reason strings.

--use solc_version
Specify the solc version, or a path to a local solc, to build with.

Valid values are in the format x.y.z, solc:x.y.z or path/to/solc.

--offline
Do not access the network. Missing solc versions will not be installed.

--no-auto-detect
Do not auto-detect solc.

--ignored-error-codes error_codes
Ignore solc warnings by error code. The parameter is a comma-separated list of error codes.

--extra-output selector
Extra output to include in the contract's artifact.

Example keys: abi, storageLayout, evm.assembly, ewasm, ir, ir-optimized, metadata.

For a full description, see the Solidity docs.

---extra-output-files selector
Extra output to write to separate files.

Example keys: abi, storageLayout, evm.assembly, ewasm, ir, ir-optimized, metadata.

For a full description, see the Solidity docs.

--evm-version version
The target EVM version.

Project Options

--build-info
Generate build info files.

--build-info-path path
Output path to directory that build info files will be written to.

--root path
The project's root path. By default, this is the root directory of the current git repository, or the current working directory.

-c path
--contracts path
The contracts source directory.
Environment: DAPP_SRC

--lib-paths path
The path to the library folder.

-r remappings
--remappings remappings
The project's remappings.

The parameter is a comma-separated list of remappings in the format <source>=<dest>.

--cache-path path
The path to the compiler cache.

--config-path file
Path to the config file.

--hh
--hardhat
This is a convenience flag, and is the same as passing --contracts contracts --lib-paths node-modules.

-o path
--out path
The project's artifacts directory.

--silent
Suppress all output

Common Options

-h
--help
Prints help information.

EXAMPLES

Execute the run() function in a contract:
```
forge debug src/Contract.sol
```
Open a script in the debugger:
```
forge debug src/Contract.sol --debug
```

Execute the foo() function in a contract:

forge debug src/Contract.sol --sig "foo()"

Execute a contract with a function that takes parameters:

forge debug src/Contract.sol --sig "foo(string,uint256)" "hello" 100

Execute a contract with raw calldata:

forge debug src/Contract.sol --sig "0x..."