SLYP

Stephen Lints Your Python

Table of Contents

• Hi
• Installation
• Usage
• Implemented Rules
• License

Hi

:wave:

I'm Stephen. I'm going to lint your Python code.

I wrote this linter because nothing else out there implemented these rules, and some of them needed CST (rather than AST), so there was no plugin framework (e.g. flake8 plugins) which I could use. I hope it helps you catch slyp-ups.

Installation

slyp is a python package and can be run as a pre-commit hook.

On supported python versions, it should be installed with

pip install slyp

Usage

Either use it as a CLI tool:

slyp src/

Or as a pre-commit hook using the following pre-commit-config.yaml:

- repo: https://github.com/sirosen/slyp
  rev: 0.1.0
  hooks:
    - id: slyp

Options and Arguments

[files...]: If passed positional arguments, slyp will treat them as filenames to check. Otherwise, it will search the current directory for python files.

-v/--verbose: Enable more verbose output

--use-git-ls: Find files to check by doing a git ls-files call and filtering the results to files which appear to be python. This is mutually exclusive with any filename arguments.

--disable CODES: Pass a comma-delimited list of codes to turn off.

--enable CODES: Pass a comma-delimited list of codes to turn on.

Implemented Rules

E is for "error" (you should probably change this)

W is for "warning" (you might want to change this)

Some warnings are disabled by default; enable them with --enable.

E100

'unnecessary string concat'

x = "foo " "bar"

W101

'unparenthesized multiline string concat in keyword arg'

foo(
    bar="alpha "
    "beta"
)

W102

'unparenthesized multiline string concat in dict value'

{
    "foo": "alpha "
    "beta"
}

W103

'unparenthesized multiline string concat in collection type'

x = (  # a tuple
    "alpha "
    "beta",
    "gamma"
)
x = {  # or a set
    "alpha "
    "beta",
    "gamma"
}

W120

'unparenthesized multiline union in parameter annotation'

def foo(
    x: int |
    str
):
    return x

E110

'returning a variable checked as None, rather than returning None'

if x is None:
    return x  # should be `return None`

W200

'two AST branches have identical contents'

if x is True:
    return y + 1
else:
    # some comment
    return y + 1

W201

disabled by default

'two AST branches have identical trivial contents'

if x is True:
    return
else:
    return

W202

disabled by default

'two non-adjacent AST branches have identical contents'

if x is True:
    return foo(bar())
elif y is True:
    return 0
elif z is True:
    return 1
else:
    return foo(bar())

W203

disabled by default

'two non-adjacent AST branches have identical trivial contents'

if x is True:
    return None
elif y is True:
    return 0
elif z is True:
    return 1
else:
    return None

License

slyp is distributed under the terms of the MIT license.