To help you get started, we've collected the most common ways that @truffle/debugger is being used within popular public projects.

trufflesuite / truffle / packages / core / lib / debug / printer.js View on Github

this.select = expr => {
      let selector, result;

      try {
        selector = expr
          .split(".")
          .filter(next => next.length > 0)
          .reduce((sel, next) => sel[next], selectors);
      } catch (_) {
        throw new Error("Unknown selector: %s", expr);
      }

      // throws its own exception
      result = this.session.view(selector);

      return result;
    };

View more ways to use @truffle/debugger

@truffle/debugger

Portable Solidity debugger library, for use with or without Truffle.

Features:

• Solidity stepping and breakpoints
• Variable inspection
• Watch expressions
• and more!

API Documentation

API Documentation for this library can be found at trufflesuite.github.io/truffle-debugger.

Library Usage

⚠️ This documentation is currently a work in progress. Please see the reference integration provided by the truffle debug command.

Required Parameters

To start a @truffle/debugger session, you'll need the following:

• txHash - A transaction hash (prefixed with 0x), for the transaction to debug
• provider - A web3 provider instance (see web3.js)
• contracts - An array of contract objects, with the following properties:
  • contractName - The name of the contract
  • source - The full Solidity source code
  • sourcePath - (optional) the path to the Solidity file on disk
  • ast - The Solidity compiler's output AST (new style, not legacyAST)
  • binary - 0x-prefixed string with the binary used to create a contract instance
  • sourceMap - The Solidity compiler output source map for the creation binary
  • deployedBinary - 0x-prefixed string with the on-chain binary for a contract instance
  • deployedSourceMap - The source map corresponding to the on-chain binary (from the Solidity compiler)

Optionally (and recommended), you can also provide a files argument:

• files - An array of sourcePaths representing file indexes (from solc or @truffle/compile-solidity)

Invocation

1. Start the debugger session by constructing a Debugger instance with .forTx() and then .connect() to it:

import Debugger from "@truffle/debugger";

let bugger = await Debugger
  .forTx(txHash, { contracts, files, provider });

let session = bugger.connect();

2. Resolve the session's ready() promise:

await session.ready();

3. Use the provided public methods on the session instance in order to step through the trace for the transaction:

session.stepNext();
session.stepOver();
session.stepInto();

4. Access data provided by the debugger via the session.view() interface, and the provided selectors:

let { ast, data, evm, solidity, trace } = Debugger.selectors;

let variables = session.view(data.current.identifiers.native);
let sourceRange = session.view(solidity.current.sourceRange);

Useful API Docs References

• Session class docs
• Docs for selectors:
  • ast selectors
  • data selectors
  • evm selectors
  • solidity selectors
  • trace selectors

Contributing

It's our goal that this library should serve as a reliable and well-maintained tool for the Solidity ecosystem. Ultimately, we hope to support all language features and meet the varied requirements of a mature debugging library.

We believe that a good Solidity debugger belongs to the community. We welcome, with our most humble gratitude, any and all community efforts in bringing this debugger closer to that goal. If you find something broken or missing, please open an issue!

Some other ideas for how to get involved:

• Bug fix PRs
• Documentation improvements
• Additional tests - unit tests and integration
• Technical discussion (ways to improve architecture, etc.)

Thank you for all the continued support. 🙇