Notes

• flake8-class-attributes-order.
• astpretty.
• babi (text editor).
• self.generic_visit(node): call it at the end of each visit_* method for the recursion to continue.
• attrs:
  • "Classes without boilerplate".
  • No need to implement object protocols (dunder methods).
  • "It does nothing dynamic at runtime, hence zero runtime overhead."
  • __attrs_post_init__ method.
• Dict vs. slotted classes.
• poetry add flake8@^3.0.0 attrs.
• flake8 formatter.py flake8_import_conventions --jobs 1.
• poetry install --no-root (don't install this package).
• import typing as t (flake8-annotations).
• import geopandas (source).
• https://github.com/asottile/flake8-2020/commit/10ba36520cca00ecbc812b2b96fcaaf9f8999c06
• Poetry:
  • https://python-poetry.org/docs/#installing-with-the-official-installer
  • poetry --version (1.3.2)
  • poetry init (https://python-poetry.org/docs/basic-usage/#initialising-a-pre-existing-project)
  • https://python-poetry.org/docs/dependency-specification/#exact-requirements
  • poetry add attrs
  • poetry add mypy black bandit pytest --group dev
  • poetry add isort@^5.11.5 --group dev or poetry add isort --group dev --allow-prereleases (PyCQA/isort#2084 + https://pypi.org/project/isort/6.0.0b2/#history + PyCQA/isort#2083)
  • flake8 = ">=5" (https://github.com/asottile/flake8-2020/blob/v1.7.0/setup.cfg#L25)
  • https://python-poetry.org/docs/cli/#add (Allow >=2.0.5 versions, without upper bound)
  • poetry config virtualenvs.in-project true --local
  • poetry env remove --all
  • poetry config --list
  • https://python-poetry.org/docs/pyproject/#classifiers
  • poetry add tomark --group dev
• https://www.attrs.org/en/latest/index.html#getting-started
• Delete local tag: git tag -d v0.0.1
• import seaborn as sns: https://seaborn.pydata.org/installing.html
• Path: /mnt/c/Users/johnn/Documents/GitHub/flake8-import-conventions
• https://import-as.github.io/
• https://github.com/marcgibbons/flake8-datetime-import

Snippets

Minimal boilerplate for the Plugin class:

import ast
import importlib.metadata
from typing import Any, Generator, Tuple, Type


class Plugin:
    name = __name__
    version = importlib.metadata.version(__name__)

    def __init__(self, tree: ast.AST) -> None:
        # The AST that represents a single file
        self._tree = tree

    def run(self) -> Generator[Tuple[int, int, str, Type[Any]], None, None]:
        # Tuple[line number, character offset, message]
        # Type[Any] is not being used (use `type(self)`)
        pass

Syntactic sugar for attr.ib(default=attr.Factory(f)):

@attr.s
class C(object):
    x = attr.ib(factory=list)
    # instead of
    # x = attr.ib(default=attr.Factory(list))

from X import ... is not allowed. X must be imported as a module. (from Marc Gibbons' flake8-datetime-import plugin):

ERRORS = {
    "DTI100": (
        "`from datetime import ...` is not allowed. `datetime` must be "
        "imported as a module."
    ),
}


class Visitor(ast.NodeVisitor):
    def __init__(self):
        self.problems = []

    def visit_ImportFrom(self, node):
        if node.module == "datetime":
            self.problems.append((node.lineno, node.col_offset, "DTI100"))
        if node.module == "time":
            self.problems.append((node.lineno, node.col_offset, "DTI200"))

        self.generic_visit(node)