chore: Implement PEP 563 deferred annotation resolution (#440)

- Add `from __future__ import annotations` to defer annotation resolution and reduce unnecessary runtime computations during type checking
- Enable Ruff checks for PEP-compliant annotations:
  - [non-pep585-annotation (UP006)](https://docs.astral.sh/ruff/rules/non-pep585-annotation/)
  - [non-pep604-annotation (UP007)](https://docs.astral.sh/ruff/rules/non-pep604-annotation/)

For more details on PEP 563, see: https://peps.python.org/pep-0563/

CHANGES

@@ -6,6 +6,17 @@
 
 ### Development
 
+#### chore: Implement PEP 563 deferred annotation resolution (#440)
+
+- Add `from __future__ import annotations` to defer annotation resolution and reduce unnecessary runtime computations during type checking.
+- Enable Ruff checks for PEP-compliant annotations:
+  - [non-pep585-annotation (UP006)](https://docs.astral.sh/ruff/rules/non-pep585-annotation/)
+  - [non-pep604-annotation (UP007)](https://docs.astral.sh/ruff/rules/non-pep604-annotation/)
+
+For more details on PEP 563, see: https://peps.python.org/pep-0563/
+
+### Development
+
 - Relax `types-docutils` version constraint (#418)
 
 ## django-docutils 0.28.0 (2024-12-20)

docs/conf.py

@@ -1,6 +1,8 @@
 """Sphinx configuration for Django Docutils."""
 
 # flake8: noqa: E501
+from __future__ import annotations
+
 import inspect
 import os
 import pathlib
@@ -77,7 +79,7 @@
 html_extra_path = ["manifest.json"]
 html_theme = "furo"
 html_theme_path: list[str] = []
-html_theme_options: dict[str, t.Union[str, list[dict[str, str]]]] = {
+html_theme_options: dict[str, str | list[dict[str, str]]] = {
     "light_logo": "img/icons/logo.svg",
     "dark_logo": "img/icons/logo-dark.svg",
     "footer_icons": [
@@ -147,7 +149,7 @@
 }
 
 
-def linkcode_resolve(domain: str, info: dict[str, str]) -> t.Union[None, str]:
+def linkcode_resolve(domain: str, info: dict[str, str]) -> None | str:
     """
     Determine the URL corresponding to Python object.
 
@@ -217,13 +219,13 @@ def linkcode_resolve(domain: str, info: dict[str, str]) -> t.Union[None, str]:
     )
 
 
-def remove_tabs_js(app: "Sphinx", exc: Exception) -> None:
+def remove_tabs_js(app: Sphinx, exc: Exception) -> None:
     """Fix for sphinx-inline-tabs#18."""
     if app.builder.format == "html" and not exc:
         tabs_js = pathlib.Path(app.builder.outdir) / "_static" / "tabs.js"
         tabs_js.unlink(missing_ok=True)
 
 
-def setup(app: "Sphinx") -> None:
+def setup(app: Sphinx) -> None:
     """Sphinx setup hook."""
     app.connect("build-finished", remove_tabs_js)

pyproject.toml

@@ -195,16 +195,25 @@ select = [
   "PERF", # Perflint
   "RUF", # Ruff-specific rules
   "D", # pydocstyle
+  "FA100",  # future annotations
 ]
 ignore = [
   "COM812", # missing trailing comma, ruff format conflict
 ]
+extend-safe-fixes = [
+  "UP006",
+  "UP007",
+]
+pyupgrade.keep-runtime-typing = false
 
 [tool.ruff.lint.isort]
 known-first-party = [
   "django_docutils",
 ]
 combine-as-imports = true
+required-imports = [
+  "from __future__ import annotations",
+]
 
 [tool.ruff.lint.pydocstyle]
 convention = "numpy"
@@ -243,9 +252,10 @@ exclude_also = [
   "if settings.DEBUG",
   "raise AssertionError",
   "raise NotImplementedError",
-  "if 0:",
   "if __name__ == .__main__.:",
   "if TYPE_CHECKING:",
+  "if t.TYPE_CHECKING:",
   "class .*\\bProtocol\\):",
   "@(abc\\.)?abstractmethod",
+  "from __future__ import annotations",
 ]

src/django_docutils/__about__.py

@@ -1,5 +1,7 @@
 """Metadata package for Django Docutils."""
 
+from __future__ import annotations
+
 __title__ = "django-docutils"
 __package_name__ = "django_docutils"
 __description__ = "Docutils (a.k.a. reStructuredText, reST, RST) support for django."

src/django_docutils/_internal/types.py

@@ -7,17 +7,19 @@
 .. _typeshed's: https://github.com/python/typeshed/blob/5df8de7/stdlib/_typeshed/__init__.pyi#L115-L118
 """  # E501
 
-from typing import TYPE_CHECKING, Union
+from __future__ import annotations
 
-if TYPE_CHECKING:
+import typing as t
+
+if t.TYPE_CHECKING:
     from os import PathLike
 
     from typing_extensions import TypeAlias
 
-StrPath: "TypeAlias" = Union[str, "PathLike[str]"]  # stable
+StrPath: TypeAlias = t.Union[str, "PathLike[str]"]  # stable
 """:class:`os.PathLike` or :class:`str`"""
 
-StrOrBytesPath: "TypeAlias" = Union[
+StrOrBytesPath: TypeAlias = t.Union[
     str,
     bytes,
     "PathLike[str]",

src/django_docutils/exc.py

@@ -1,5 +1,7 @@
 """Exceptions for Django Docutils."""
 
+from __future__ import annotations
+
 
 class DjangoDocutilsException(Exception):
     """Base exception for Django Docutils package."""

src/django_docutils/lib/directives/code.py

@@ -36,9 +36,10 @@
 :license: BSD, see LICENSE for details.
 """
 
+from __future__ import annotations
+
 import re
 import typing as t
-from collections.abc import Callable
 
 from docutils import nodes
 from docutils.parsers.rst import Directive, directives
@@ -48,6 +49,8 @@
 from pygments.lexers.special import TextLexer
 
 if t.TYPE_CHECKING:
+    from collections.abc import Callable
+
     from pygments.formatter import Formatter
 
 
@@ -72,7 +75,7 @@ def patch_bash_session_lexer() -> None:
 DEFAULT = HtmlFormatter(cssclass="highlight code-block", noclasses=INLINESTYLES)
 
 #: Add name -> formatter pairs for every variant you want to use
-VARIANTS: dict[str, "Formatter[str]"] = {
+VARIANTS: dict[str, Formatter[str]] = {
     # 'linenos': HtmlFormatter(noclasses=INLINESTYLES, linenos=True),
 }
 

src/django_docutils/lib/directives/registry.py

@@ -1,5 +1,7 @@
 """Register douctils directives for django-docutils."""
 
+from __future__ import annotations
+
 from django.utils.module_loading import import_string
 from docutils.parsers.rst import directives
 

src/django_docutils/lib/metadata/extract.py

@@ -1,13 +1,13 @@
 """Title, Subtitle, and Metadata extraction of reStructuredText."""
 
-import typing as t
+from __future__ import annotations
 
 from django.template.defaultfilters import truncatewords
 from django.utils.html import strip_tags
 from docutils import nodes
 
 
-def extract_title(document: nodes.document) -> t.Optional[str]:
+def extract_title(document: nodes.document) -> str | None:
     """Return the title of the document.
 
     Parameters
@@ -77,7 +77,7 @@ def extract_metadata(document: nodes.document) -> dict[str, str]:
     return output
 
 
-def extract_subtitle(document: nodes.document) -> t.Optional[str]:
+def extract_subtitle(document: nodes.document) -> str | None:
     """Return the subtitle of the document."""
     for node in document.traverse(nodes.PreBibliographic):  # type:ignore
         if isinstance(node, nodes.subtitle):

src/django_docutils/lib/metadata/process.py

@@ -30,6 +30,8 @@ def process_datetime(metadata):
 See *processors.py* for more examples.
 """
 
+from __future__ import annotations
+
 from django.utils.module_loading import import_string
 
 from django_docutils.lib.settings import DJANGO_DOCUTILS_LIB_RST

src/django_docutils/lib/metadata/processors.py

@@ -1,5 +1,7 @@
 """Metadata processing for Django Docutils."""
 
+from __future__ import annotations
+
 import datetime
 import typing as t
 

src/django_docutils/lib/metadata/tests/test_extract.py

@@ -1,6 +1,8 @@
 """Test metadata and title extraction from reStructuredText."""
 
-import pathlib
+from __future__ import annotations
+
+import typing as t
 
 from django.utils.encoding import force_bytes
 from docutils.core import publish_doctree
@@ -12,6 +14,9 @@
 )
 from django_docutils.lib.settings import DJANGO_DOCUTILS_LIB_RST
 
+if t.TYPE_CHECKING:
+    import pathlib
+
 
 def test_extract_title() -> None:
     """Assert title extraction from reStructuredText."""

src/django_docutils/lib/metadata/tests/test_process.py

@@ -1,5 +1,7 @@
 """Test docutils metadata (docinfo) processing in Django Docutils."""
 
+from __future__ import annotations
+
 import datetime
 
 from django.utils.encoding import force_bytes

src/django_docutils/lib/publisher.py

@@ -1,13 +1,14 @@
 """Docutils Publisher fors for Django Docutils."""
 
+from __future__ import annotations
+
 import typing as t
 
 from django.utils.encoding import force_bytes, force_str
 from django.utils.safestring import mark_safe
 from docutils import io, nodes
 from docutils.core import Publisher, publish_doctree as docutils_publish_doctree
 from docutils.readers.doctree import Reader
-from docutils.writers.html5_polyglot import Writer
 
 from .directives.registry import register_django_docutils_directives
 from .roles.registry import register_django_docutils_roles
@@ -17,19 +18,20 @@
 
 if t.TYPE_CHECKING:
     from docutils import SettingsSpec
+    from docutils.writers.html5_polyglot import Writer
 
 docutils_settings = DJANGO_DOCUTILS_LIB_RST.get("docutils", {})
 
 
 def publish_parts_from_doctree(
     document: nodes.document,
-    destination_path: t.Optional[str] = None,
-    writer: t.Optional[Writer] = None,
+    destination_path: str | None = None,
+    writer: Writer | None = None,
     writer_name: str = "pseudoxml",
-    settings: t.Optional[t.Any] = None,
-    settings_spec: "t.Optional[SettingsSpec]" = None,
-    settings_overrides: t.Optional[t.Any] = None,
-    config_section: t.Optional[str] = None,
+    settings: t.Any | None = None,
+    settings_spec: SettingsSpec | None = None,
+    settings_overrides: t.Any | None = None,
+    config_section: str | None = None,
     enable_exit_status: bool = False,
 ) -> dict[str, str]:
     """Render docutils doctree into docutils parts."""
@@ -56,8 +58,8 @@ def publish_parts_from_doctree(
 
 def publish_toc_from_doctree(
     doctree: nodes.document,
-    writer: t.Optional[Writer] = None,
-) -> t.Optional[str]:
+    writer: Writer | None = None,
+) -> str | None:
     """Publish table of contents from docutils doctree."""
     if not writer:
         writer = DjangoDocutilsWriter()
@@ -98,7 +100,7 @@ def publish_toc_from_doctree(
 
 
 def publish_doctree(
-    source: t.Union[str, bytes],
+    source: str | bytes,
     settings_overrides: t.Any = docutils_settings,
 ) -> nodes.document:
     """Split off ability to get doctree (a.k.a. document).
@@ -139,8 +141,8 @@ class PublishHtmlDocTreeKwargs(TypedDict):
 
 def publish_html_from_source(
     source: str,
-    **kwargs: "Unpack[PublishHtmlDocTreeKwargs]",
-) -> t.Optional[str]:
+    **kwargs: Unpack[PublishHtmlDocTreeKwargs],
+) -> str | None:
     """Return HTML from reStructuredText source string."""
     doctree = publish_doctree(source)
     return publish_html_from_doctree(doctree, **kwargs)
@@ -150,7 +152,7 @@ def publish_html_from_doctree(
     doctree: nodes.document,
     show_title: bool = True,
     toc_only: bool = False,
-) -> t.Optional[str]:
+) -> str | None:
     """Return HTML from reStructuredText document (doctree).
 
     Parameters

src/django_docutils/lib/roles/common.py

@@ -1,5 +1,7 @@
 """Core parts for Django Docutils roles."""
 
+from __future__ import annotations
+
 import typing as t
 
 from docutils import nodes, utils
@@ -13,9 +15,9 @@
 def generic_url_role(
     name: str,
     text: str,
-    url_handler_fn: "UrlHandlerFn",
-    innernodeclass: type[t.Union[nodes.Text, nodes.TextElement]] = nodes.Text,
-) -> "RoleFnReturnValue":
+    url_handler_fn: UrlHandlerFn,
+    innernodeclass: type[nodes.Text | nodes.TextElement] = nodes.Text,
+) -> RoleFnReturnValue:
     """Docutils Role for Django Docutils.
 
     This generic role also handles explicit titles (``:role:`yata yata <target>```)
@@ -78,8 +80,8 @@ def url_handler(target):
 def generic_remote_url_role(
     name: str,
     text: str,
-    url_handler_fn: "RemoteUrlHandlerFn",
-    innernodeclass: type[t.Union[nodes.Text, nodes.TextElement]] = nodes.Text,
+    url_handler_fn: RemoteUrlHandlerFn,
+    innernodeclass: type[nodes.Text | nodes.TextElement] = nodes.Text,
 ) -> tuple[list[nodes.reference], list[t.Any]]:
     """Docutils Role that can call an external data source for title and URL.
 

src/django_docutils/lib/roles/email.py

@@ -1,11 +1,15 @@
 """Email role for docutils."""
 
-import typing as t
+from __future__ import annotations
 
-from docutils.parsers.rst.states import Inliner
+import typing as t
 
 from .common import generic_url_role
-from .types import RoleFnReturnValue
+
+if t.TYPE_CHECKING:
+    from docutils.parsers.rst.states import Inliner
+
+    from .types import RoleFnReturnValue
 
 
 def email_role(
@@ -14,8 +18,8 @@ def email_role(
     text: str,
     lineno: int,
     inliner: Inliner,
-    options: t.Optional[dict[str, t.Any]] = None,
-    content: t.Optional[str] = None,
+    options: dict[str, t.Any] | None = None,
+    content: str | None = None,
 ) -> RoleFnReturnValue:
     """Role for linking to email articles.