Rework infrastructure for linting

Run mypy checks outside of `pre-commit` for completeness, and move to
Ruff for style checks.

Author: pradyunsg

.flake8

@@ -34,18 +34,12 @@ repos:
       - id: forbid-new-submodules
       - id: trailing-whitespace
 
-  - repo: https://github.com/PyCQA/flake8
-    rev: 6.1.0
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    # Ruff version.
+    rev: v0.0.287
     hooks:
-      - id: flake8
-
-  - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v1.4.1
-    hooks:
-      - id: mypy
-        args: [--disallow-untyped-defs, --ignore-missing-imports]
-        files: src/.*\.py$
-        additional_dependencies: [types-docutils]
+      - id: ruff
+        args: [--fix, --exit-non-zero-on-fix]
 
   - repo: https://github.com/PyCQA/pydocstyle
     rev: 6.3.0

.pre-commit-config.yaml

@@ -84,6 +84,12 @@ def docs_live(session):
 
 @nox.session(reuse_venv=True)
 def lint(session):
+    session.notify("lint-pre-commit")
+    session.notify("lint-mypy")
+
+
+@nox.session(reuse_venv=True, name="lint-pre-commit")
+def lint_pre_commit(session):
     session.install("pre-commit")
 
     args = list(session.posargs)
@@ -94,6 +100,14 @@ def lint(session):
     session.run("pre-commit", "run", *args)
 
 
+@nox.session(reuse_venv=True, name="lint-mypy")
+def lint_mypy(session):
+    session.install(
+        "-e", ".", "mypy", "types-docutils", "types-Pygments", "types-beautifulsoup4"
+    )
+    session.run("mypy", "src")
+
+
 @nox.session
 def test(session):
     session.install("-e", ".", "-r", "tests/requirements.txt")

noxfile.py

@@ -4,9 +4,7 @@ build-backend = "sphinx_theme_builder"
 
 [tool.sphinx-theme-builder]
 node-version = "18.16.0"
-additional-compiled-static-assets = [
-  "styles/furo-extensions.css",
-]
+additional-compiled-static-assets = ["styles/furo-extensions.css"]
 
 [project]
 name = "furo"
@@ -22,10 +20,8 @@ dependencies = [
   "pygments >= 2.7",
 ]
 
-license = { file = "LICENSE"}
-authors = [
-    {name = "Pradyun Gedam", email = "mail@pradyunsg.me"},
-]
+license = { file = "LICENSE" }
+authors = [{ name = "Pradyun Gedam", email = "mail@pradyunsg.me" }]
 classifiers = [
   "Framework :: Sphinx",
   "Framework :: Sphinx :: Theme",
@@ -45,7 +41,13 @@ classifiers = [
 ]
 
 [project.entry-points]
-"sphinx.html_themes" = {furo = "furo"}
+"sphinx.html_themes" = { furo = "furo" }
 
 [project.urls]
 GitHub = "https://github.com/pradyunsg/furo"
+
+[tool.mypy]
+strict = true
+
+[tool.ruff]
+ignore = ["E501"]

pyproject.toml

@@ -7,7 +7,7 @@
 import os
 from functools import lru_cache
 from pathlib import Path
-from typing import Any, Dict, Iterator, List, Optional
+from typing import Any, Dict, Iterator, List, Optional, cast
 
 import sphinx.application
 from docutils import nodes
@@ -71,7 +71,7 @@ def has_not_enough_items_to_show_toc(
 
     toctree = TocTree(builder.env).get_toc_for(docname, builder)
     try:
-        self_toctree = toctree[0][1]
+        self_toctree = toctree[0][1]  # type: ignore[index]
     except IndexError:
         val = True
     else:
@@ -84,8 +84,8 @@ def get_pygments_style_colors(
     style: Style, *, fallbacks: Dict[str, str]
 ) -> Dict[str, str]:
     """Get background/foreground colors for given pygments style."""
-    background = style.background_color
-    text_colors = style.style_for_token(Text)
+    background = style.background_color  # type: ignore[attr-defined]
+    text_colors = style.style_for_token(Text)  # type: ignore[attr-defined]
     foreground = text_colors["color"]
 
     if not background:
@@ -172,9 +172,10 @@ def _add_asset_hashes(static: List[str], add_digest_to: List[str]) -> None:
                 "theme-provide assets such as `html_style`."
             )
 
-        if "?digest=" in static[index].filename:  # make this idempotent
+        # Make this idempotent
+        if "?digest=" in static[index].filename:  # type: ignore[attr-defined]
             continue
-        static[index].filename = _asset_hash(asset)  # type: ignore
+        static[index].filename = _asset_hash(asset)  # type: ignore[attr-defined]
 
 
 def _html_page_context(
@@ -201,9 +202,11 @@ def _html_page_context(
     # Values computed from page-level context.
     context["furo_navigation_tree"] = _compute_navigation_tree(context)
     context["furo_hide_toc"] = _compute_hide_toc(
-        context, builder=app.builder, docname=pagename
+        context, builder=cast(StandaloneHTMLBuilder, app.builder), docname=pagename
     )
 
+    assert _KNOWN_STYLES_IN_USE["light"]
+    assert _KNOWN_STYLES_IN_USE["dark"]
     # Inject information about styles
     context["furo_pygments"] = {
         "light": get_pygments_style_colors(
@@ -248,10 +251,10 @@ def _builder_inited(app: sphinx.application.Sphinx) -> None:
 
     builder = app.builder
     assert (
-        builder.highlighter is not None
+        builder.highlighter is not None  # type: ignore[attr-defined]
     ), "there should be a default style known to Sphinx"
     assert (
-        builder.dark_highlighter is None
+        builder.dark_highlighter is None  # type: ignore[attr-defined]
     ), "this shouldn't be a dark style known to Sphinx"
     update_known_styles_state(app)
 
@@ -273,17 +276,25 @@ def update_known_styles_state(app: sphinx.application.Sphinx) -> None:
 
 
 def _get_light_style(app: sphinx.application.Sphinx) -> Style:
-    return app.builder.highlighter.formatter_args["style"]
+    # fmt: off
+    # For https://github.com/psf/black/issues/3869
+    return (
+        app  # type: ignore[no-any-return]
+            .builder
+            .highlighter # type: ignore[attr-defined]
+            .formatter_args["style"]
+        )
+    # fmt: on
 
 
 def _get_dark_style(app: sphinx.application.Sphinx) -> Style:
     dark_style = app.config.pygments_dark_style
-    return PygmentsBridge("html", dark_style).formatter_args["style"]
+    return cast(Style, PygmentsBridge("html", dark_style).formatter_args["style"])
 
 
-def _get_styles(formatter: HtmlFormatter, *, prefix: str) -> Iterator[str]:
+def _get_styles(formatter: HtmlFormatter[str], *, prefix: str) -> Iterator[str]:
     """Get styles out of a formatter, where everything has the correct prefix."""
-    for line in formatter.get_linenos_style_defs():
+    for line in formatter.get_linenos_style_defs():  # type: ignore[no-untyped-call]
         yield f"{prefix} {line}"
     yield from formatter.get_background_style_defs(prefix)
     yield from formatter.get_token_style_defs(prefix)

src/furo/__init__.py

@@ -20,7 +20,7 @@
 from docutils import nodes
 from docutils.statemachine import StringList
 from sphinx.application import Sphinx
-from sphinx.directives import SphinxDirective
+from sphinx.directives import SphinxDirective  # type: ignore[attr-defined]
 
 
 def _split_by_language(block_text: str) -> Tuple[str, str]: