Refurb Plugin Example

This repo is meant to be a good starting point for those who are looking to make plugins for Refurb.

For illustrative purposes, this plugin will emit an error when the following print statement is found:

print("Hello world!")

Setup

First things first, fork this repo. Make sure to change the name, but keep the refurb- prefix (for naming convention sake).

Next, clone:

$ git clone https://github.com/USERNAME/refurb-your-plugin
$ cd refurb-your-plugin

Of course, replacing refurb-your-plugin with the name you picked.

Then, update the pyproject.toml file with the your information. You can run the setup.sh script to do this for you, which will ask you a series of questions. If the script does not work, you will have to update it manually (you should only need to update the first two sections).

Check Discovery

In order for Refurb to find and use your check, 2 conditions must be met:

1. You must export a class that starts with Error, which will contain the error metadata. Note:

• It must derive from Error
• It cannot be named ErrorCode

2. You must have a function called check, which is the entry point for a given check.

The definition for a check function looks something like this:

def check(node: CallExpr, errors: list[Error]) -> None:
    ...

Where CallExpr is the node you want to accept, and errors is where you append an error if one occurs. You can accept multiple node types using a type union, like so:

def check(node: UnaryExpr | OpExpr, errors: list[Error]) -> None:
    ...

This check will accept both unary and binary expressions.

Any nested folders must contain an __init__.py file. This might not be 100% necessary, but from what I can tell, it is best to add it in anyways.