📐 Smart Contract Guidelines

When creating a new smart contract project, use the guidelines below to ensure your project meets our basic standards of quality.

Security

Re-entrancy

Any external or public functions need to be analyzed to determine whether the contract can be attacked if a user re-enters that function or another.

Safe ERC20 Usage

ERC20 token interactions should always use SafeERC20 safeApprove and safeTransferFrom in the OpenZeppelin library.

Math Overflow and Underflow

Any math operations need to be checked for overflow and underflow conditions, using SafeMath or similar.

Trusted External Calls

The contract should minimize trust in external calls.

Optimizations

  • All external / public functions should return a value when possible (to save gas)

  • Structs must be tightly packed

  • Hardcoded integers and strings should be constants

  • Contract members that don't change should be immutable

Conventions

Typed Arguments

All arguments, whether to an event or function, must be typed when possible. address types should be avoided in favour of contract or interface types

Logs Emitted

Events must be emitted for any significant state change or event.

Grammar

Names and documentation must be spelled correctly with no grammatical errors.

Documentation

Readme

A complete readme must be included with the project. It needs:

  • a complete description

  • usage

  • setup instructions

  • all test commands

  • deployment instructions and information

  • information on any additional scripts

Natspec

Contracts must have (at minimum):

  • @title: short title. shouldn't repeat the description

  • @notice: descriptive enough so that the reader understands the intent of the contract.

Functions must have (at minimum):

  • @notice: explain what the function does

  • @param: explain each parameter

  • @return: explain the return param(s)

Events must have (at minimum):

  • @notice: describe when the event is emitted

  • @param: describe each of the args

Testing

Unit Tests

  • There must be a test suite for each contract

  • Each unit test should mock out contract dependencies using Waffle or Smock

  • Contract functions should be tested in isolation

  • Unit tests must run locally; i.e. they do not connect to a remote node.

Code Coverage

  • Coverage must exceed 95%

Fork Test

  • A fork test script tests the contracts in the real world

  • At a minimum the test must execute the "happy path" for the code.

Repository Badges

  • Coverage badge must be included (we use Coveralls)

  • Github Workflow badge for the fork test

  • Github Workflow badge for the unit tests