Make flake8 an optional dependency (#348)

Author: jakkdl

.github/workflows/ci.yml

@@ -44,6 +44,8 @@ jobs:
               run: python -m tox -e flake8_6
             - name: Run tests with flake8_7+
               run: python -m tox -e flake8_7
+            - name: Run tests without flake8
+              run: python -m tox -e noflake8 -- --no-cov
 
     slow_tests:
         runs-on: ubuntu-latest

docs/changelog.rst

@@ -4,6 +4,10 @@ Changelog
 
 `CalVer, YY.month.patch <https://calver.org/>`_
 
+25.2.3
+=======
+- No longer require ``flake8`` for installation... so if you require support for config files you must install ``flake8-async[flake8]``
+
 25.2.2
 =======
 - :ref:`ASYNC113 <async113>` now only triggers on ``trio.[serve_tcp, serve_ssl_over_tcp, serve_listeners, run_process]``, instead of accepting anything as the attribute base. (e.g. :func:`anyio.run_process` is not startable).

docs/usage.rst

@@ -17,7 +17,7 @@ install and run through flake8
 
 .. code-block:: sh
 
-   pip install flake8 flake8-async
+   pip install flake8-async[flake8]
    flake8 .
 
 .. _install-run-pre-commit:
@@ -33,10 +33,10 @@ adding the following to your ``.pre-commit-config.yaml``:
    minimum_pre_commit_version: '2.9.0'
    repos:
    - repo: https://github.com/python-trio/flake8-async
-     rev: 25.2.2
+     rev: 25.2.3
      hooks:
        - id: flake8-async
-         # args: [--enable=ASYNC, --disable=ASYNC9, --autofix=ASYNC]
+         # args: ["--enable=ASYNC100,ASYNC112", "--disable=", "--autofix=ASYNC"]
 
 This is often considerably faster for large projects, because ``pre-commit``
 can avoid running ``flake8-async`` on unchanged files.

flake8_async/__init__.py

@@ -38,7 +38,7 @@
 
 
 # CalVer: YY.month.patch, e.g. first release of July 2022 == "22.7.1"
-__version__ = "25.2.2"
+__version__ = "25.2.3"
 
 
 # taken from https://github.com/Zac-HD/shed
@@ -127,8 +127,11 @@ def options(self) -> Options:
         assert self._options is not None
         return self._options
 
-    def __init__(self, tree: ast.AST, lines: Sequence[str]):
+    def __init__(
+        self, tree: ast.AST, lines: Sequence[str], filename: str | None = None
+    ):
         super().__init__()
+        self.filename: str | None = filename
         self._tree = tree
         source = "".join(lines)
 
@@ -139,14 +142,17 @@ def from_filename(cls, filename: str | PathLike[str]) -> Plugin:  # pragma: no c
         # only used with --runslow
         with tokenize.open(filename) as f:
             source = f.read()
-        return cls.from_source(source)
+        return cls.from_source(source, filename=filename)
 
     # alternative `__init__` to avoid re-splitting and/or re-joining lines
     @classmethod
-    def from_source(cls, source: str) -> Plugin:
+    def from_source(
+        cls, source: str, filename: str | PathLike[str] | None = None
+    ) -> Plugin:
         plugin = Plugin.__new__(cls)
         super(Plugin, plugin).__init__()
         plugin._tree = ast.parse(source)
+        plugin.filename = str(filename) if filename else None
         plugin.module = cst_parse_module_native(source)
         return plugin
 
@@ -231,6 +237,13 @@ def add_options(option_manager: OptionManager | ArgumentParser):
                 " errors."
             ),
         )
+        add_argument(
+            "--per-file-disable",
+            type=parse_per_file_disable,
+            default={},
+            required=False,
+            help=("..."),
+        )
         add_argument(
             "--autofix",
             type=comma_separated_list,
@@ -441,3 +454,23 @@ def parse_async200_dict(raw_value: str) -> dict[str, str]:
             )
         res[split_values[0]] = split_values[1]
     return res
+
+
+# not run if flake8 is installed
+def parse_per_file_disable(  # pragma: no cover
+    raw_value: str,
+) -> dict[str, tuple[str, ...]]:
+    res: dict[str, tuple[str, ...]] = {}
+    splitter = "->"
+    values = [s.strip() for s in raw_value.split(" \t\n") if s.strip()]
+    for value in values:
+        split_values = list(map(str.strip, value.split(splitter)))
+        if len(split_values) != 2:
+            # argparse will eat this error message and spit out its own
+            # if we raise it as ValueError
+            raise ArgumentTypeError(
+                f"Invalid number ({len(split_values)-1}) of splitter "
+                f"tokens {splitter!r} in {value!r}"
+            )
+        res[split_values[0]] = tuple(split_values[1].split(","))
+    return res

setup.py

@@ -34,7 +34,8 @@ def local_file(name: str) -> Path:
     license_files=[],  # https://github.com/pypa/twine/issues/1216
     description="A highly opinionated flake8 plugin for Trio-related problems.",
     zip_safe=False,
-    install_requires=["flake8>=6", "libcst>=1.0.1"],
+    install_requires=["libcst>=1.0.1"],
+    extras_require={"flake8": ["flake8>=6"]},
     python_requires=">=3.9",
     classifiers=[
         "Development Status :: 3 - Alpha",

tests/eval_files/async119.py

@@ -15,7 +15,7 @@ async def async_with():
         yield  # error: 8
 
 
-async def warn_on_yeach_yield():
+async def warn_on_each_yield():
     with open(""):
         yield  # error: 8
         yield  # error: 8

tests/test_config_and_args.py

@@ -13,6 +13,11 @@
 
 from .test_flake8_async import initialize_options
 
+try:
+    import flake8
+except ImportError:
+    flake8 = None  # type: ignore[assignment]
+
 EXAMPLE_PY_TEXT = """import trio
 with trio.move_on_after(10):
     ...
@@ -140,7 +145,7 @@ def test_run_100_autofix(
 
 def test_114_raises_on_invalid_parameter(capsys: pytest.CaptureFixture[str]):
     plugin = Plugin(ast.AST(), [])
-    # flake8 will reraise ArgumentError as SystemExit
+    # argparse will reraise ArgumentTypeError as SystemExit
     for arg in "blah.foo", "foo*", "*":
         with pytest.raises(SystemExit):
             initialize_options(plugin, args=[f"--startable-in-context-manager={arg}"])
@@ -159,6 +164,7 @@ def test_200_options(capsys: pytest.CaptureFixture[str]):
         assert all(word in err for word in (str(i), arg, "->"))
 
 
+@pytest.mark.skipif(flake8 is None, reason="flake8 is not installed")
 def test_anyio_from_config(tmp_path: Path, capsys: pytest.CaptureFixture[str]):
     assert tmp_path.joinpath(".flake8").write_text(
         """
@@ -228,6 +234,7 @@ async def foo():
     )
 
 
+@pytest.mark.skipif(flake8 is None, reason="flake8 is not installed")
 def test_200_from_config_flake8_internals(
     tmp_path: Path, capsys: pytest.CaptureFixture[str]
 ):
@@ -254,6 +261,7 @@ def test_200_from_config_flake8_internals(
     assert err_msg == out
 
 
+@pytest.mark.skipif(flake8 is None, reason="flake8 is not installed")
 def test_200_from_config_subprocess(tmp_path: Path):
     err_msg = _test_async200_from_config_common(tmp_path)
     res = subprocess.run(["flake8"], cwd=tmp_path, capture_output=True, check=False)
@@ -262,6 +270,7 @@ def test_200_from_config_subprocess(tmp_path: Path):
     assert res.stdout == err_msg.encode("ascii")
 
 
+@pytest.mark.skipif(flake8 is None, reason="flake8 is not installed")
 def test_async200_from_config_subprocess(tmp_path: Path):
     err_msg = _test_async200_from_config_common(tmp_path, code="trio200")
     res = subprocess.run(["flake8"], cwd=tmp_path, capture_output=True, check=False)
@@ -273,6 +282,7 @@ def test_async200_from_config_subprocess(tmp_path: Path):
     assert res.stdout == err_msg.encode("ascii")
 
 
+@pytest.mark.skipif(flake8 is None, reason="flake8 is not installed")
 def test_async200_from_config_subprocess_cli_ignore(tmp_path: Path):
     _ = _test_async200_from_config_common(tmp_path)
     res = subprocess.run(
@@ -288,6 +298,20 @@ def test_async200_from_config_subprocess_cli_ignore(tmp_path: Path):
 
 
 def test_900_default_off(capsys: pytest.CaptureFixture[str]):
+    res = subprocess.run(
+        ["flake8-async", "tests/eval_files/async900.py"],
+        capture_output=True,
+        check=False,
+        encoding="utf8",
+    )
+    assert res.returncode == 1
+    assert not res.stderr
+    assert "ASYNC124" in res.stdout
+    assert "ASYNC900" not in res.stdout
+
+
+@pytest.mark.skipif(flake8 is None, reason="flake8 is not installed")
+def test_900_default_off_flake8(capsys: pytest.CaptureFixture[str]):
     from flake8.main.cli import main
 
     returnvalue = main(
@@ -303,11 +327,18 @@ def test_900_default_off(capsys: pytest.CaptureFixture[str]):
 
 
 def test_910_can_be_selected(tmp_path: Path):
+    """Check if flake8 allows us to --select our 5-letter code.
+
+    But we can run with --enable regardless.
+    """
     myfile = tmp_path.joinpath("foo.py")
     myfile.write_text("""async def foo():\n    print()""")
 
+    binary = "flake8-async" if flake8 is None else "flake8"
+    select_enable = "enable" if flake8 is None else "select"
+
     res = subprocess.run(
-        ["flake8", "--select=ASYNC910", "foo.py"],
+        [binary, f"--{select_enable}=ASYNC910", "foo.py"],
         cwd=tmp_path,
         capture_output=True,
         check=False,
@@ -384,6 +415,7 @@ def _helper(*args: str, error: bool = False, autofix: bool = False) -> None:
     )
 
 
+@pytest.mark.skipif(flake8 is None, reason="flake8 is not installed")
 def test_flake8_plugin_with_autofix_fails(tmp_path: Path):
     write_examplepy(tmp_path)
     res = subprocess.run(
@@ -453,7 +485,9 @@ def test_disable_noqa_ast(
     )
 
 
+@pytest.mark.skipif(flake8 is None, reason="flake8 is not installed")
 def test_config_select_error_code(tmp_path: Path) -> None:
+    # this ... seems to work? I'm confused
     assert tmp_path.joinpath(".flake8").write_text(
         """
 [flake8]
@@ -469,6 +503,7 @@ def test_config_select_error_code(tmp_path: Path) -> None:
 
 
 # flake8>=6 enforces three-letter error codes in config
+@pytest.mark.skipif(flake8 is None, reason="flake8 is not installed")
 def test_config_ignore_error_code(tmp_path: Path) -> None:
     assert tmp_path.joinpath(".flake8").write_text(
         """
@@ -490,6 +525,7 @@ def test_config_ignore_error_code(tmp_path: Path) -> None:
 
 
 # flake8>=6 enforces three-letter error codes in config
+@pytest.mark.skipif(flake8 is None, reason="flake8 is not installed")
 def test_config_extend_ignore_error_code(tmp_path: Path) -> None:
     assert tmp_path.joinpath(".flake8").write_text(
         """
@@ -511,6 +547,7 @@ def test_config_extend_ignore_error_code(tmp_path: Path) -> None:
     assert res.returncode == 1
 
 
+@pytest.mark.skipif(flake8 is None, reason="flake8 is not installed")
 # but make sure we can disable selected codes
 def test_config_disable_error_code(tmp_path: Path) -> None:
     # select ASYNC200 and create file that induces ASYNC200

tests/test_decorator.py

@@ -3,11 +3,11 @@
 from __future__ import annotations
 
 import ast
+import sys
 from pathlib import Path
 from typing import TYPE_CHECKING
 
-from flake8.main.application import Application
-
+from flake8_async import main
 from flake8_async.base import Statement
 from flake8_async.visitors.helpers import fnmatch_qualified_name
 from flake8_async.visitors.visitor91x import Visitor91X
@@ -90,11 +90,20 @@ def test_pep614():
 
 
 file_path = str(Path(__file__).parent / "trio_options.py")
-common_flags = ["--select=ASYNC", file_path]
 
 
-def test_command_line_1(capfd: pytest.CaptureFixture[str]):
-    Application().run([*common_flags, "--no-checkpoint-warning-decorators=app.route"])
+def _set_flags(monkeypatch: pytest.MonkeyPatch, *flags: str):
+    monkeypatch.setattr(
+        sys, "argv", ["./flake8-async", "--enable=ASYNC910", file_path, *flags]
+    )
+
+
+def test_command_line_1(
+    capfd: pytest.CaptureFixture[str], monkeypatch: pytest.MonkeyPatch
+):
+    _set_flags(monkeypatch, "--no-checkpoint-warning-decorators=app.route")
+    assert main() == 0
+
     assert capfd.readouterr() == ("", "")
 
 
@@ -114,11 +123,17 @@ def test_command_line_1(capfd: pytest.CaptureFixture[str]):
 )
 
 
-def test_command_line_2(capfd: pytest.CaptureFixture[str]):
-    Application().run([*common_flags, "--no-checkpoint-warning-decorators=app"])
+def test_command_line_2(
+    capfd: pytest.CaptureFixture[str], monkeypatch: pytest.MonkeyPatch
+):
+    _set_flags(monkeypatch, "--no-checkpoint-warning-decorators=app")
+    assert main() == 1
     assert capfd.readouterr() == (expected_out, "")
 
 
-def test_command_line_3(capfd: pytest.CaptureFixture[str]):
-    Application().run(common_flags)
+def test_command_line_3(
+    capfd: pytest.CaptureFixture[str], monkeypatch: pytest.MonkeyPatch
+):
+    _set_flags(monkeypatch)
+    assert main() == 1
     assert capfd.readouterr() == (expected_out, "")

tox.ini

@@ -1,7 +1,7 @@
 # The test environment and commands
 [tox]
 # default environments to run without `-e`
-envlist = py{39,310,311,312,313}-{flake8_6,flake8_7}
+envlist = py{39,310,311,312,313}-{flake8_6,flake8_7},noflake8
 
 # create a default testenv, whose behaviour will depend on the name it's called with.
 # for CI you can call with `-e flake8_6,flake8_7` and let the CI handle python version