Use future annotations

CHANGES

@@ -19,6 +19,17 @@ $ pipx install --suffix=@next 'tmuxp' --pip-args '\--pre' --force
 
 <!-- Maintainers, insert changes / features for the next release here -->
 
+### Development
+
+#### chore: Implement PEP 563 deferred annotation resolution (#957)
+
+- 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/
+
 ## tmuxp 1.50.1 (2024-12-24)
 
 ### Development

conftest.py

@@ -8,6 +8,8 @@
 https://docs.pytest.org/en/stable/deprecations.html
 """
 
+from __future__ import annotations
+
 import logging
 import os
 import pathlib
@@ -29,7 +31,7 @@
 
 
 @pytest.fixture(autouse=USING_ZSH, scope="session")
-def zshrc(user_path: pathlib.Path) -> t.Optional[pathlib.Path]:
+def zshrc(user_path: pathlib.Path) -> pathlib.Path | None:
     """Quiets ZSH default message.
 
     Needs a startup file .zshenv, .zprofile, .zshrc, .zlogin.

docs/_ext/aafig.py

@@ -12,6 +12,8 @@
 :license: BOLA, see LICENSE for details
 """
 
+from __future__ import annotations
+
 import locale
 import logging
 import posixpath
@@ -40,9 +42,9 @@
 
 
 def merge_dict(
-    dst: dict[str, t.Optional[str]],
-    src: dict[str, t.Optional[str]],
-) -> dict[str, t.Optional[str]]:
+    dst: dict[str, str | None],
+    src: dict[str, str | None],
+) -> dict[str, str | None]:
     for k, v in src.items():
         if k not in dst:
             dst[k] = v
@@ -52,7 +54,7 @@ def merge_dict(
 def get_basename(
     text: str,
     options: dict[str, str],
-    prefix: t.Optional[str] = "aafig",
+    prefix: str | None = "aafig",
 ) -> str:
     options = options.copy()
     if "format" in options:
@@ -105,7 +107,7 @@ def run(self) -> list[nodes.Node]:
         return [image_node]
 
 
-def render_aafig_images(app: "Sphinx", doctree: nodes.Node) -> None:
+def render_aafig_images(app: Sphinx, doctree: nodes.Node) -> None:
     format_map = app.builder.config.aafig_format
     merge_dict(format_map, DEFAULT_FORMATS)
     if aafigure is None:
@@ -157,10 +159,10 @@ def __init__(self, *args: object, **kwargs: object) -> None:
 
 
 def render_aafigure(
-    app: "Sphinx",
+    app: Sphinx,
     text: str,
     options: dict[str, str],
-) -> tuple[str, str, t.Optional[str], t.Optional[str]]:
+) -> tuple[str, str, str | None, str | None]:
     """Render an ASCII art figure into the requested format output file."""
     if aafigure is None:
         raise AafigureNotInstalled
@@ -227,7 +229,7 @@ def render_aafigure(
     return relfn, outfn, None, extra
 
 
-def setup(app: "Sphinx") -> None:
+def setup(app: Sphinx) -> None:
     app.add_directive("aafig", AafigDirective)
     app.connect("doctree-read", render_aafig_images)
     app.add_config_value("aafig_format", DEFAULT_FORMATS, "html")

docs/conf.py

@@ -1,6 +1,8 @@
 # flake8: NOQA: E501
 """Sphinx documentation configuration for tmuxp."""
 
+from __future__ import annotations
+
 import contextlib
 import inspect
 import pathlib
@@ -74,7 +76,7 @@
 html_favicon = "_static/favicon.ico"
 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/tmuxp.svg",
     "dark_logo": "img/tmuxp.svg",
     "footer_icons": [
@@ -143,7 +145,7 @@
 }
 
 
-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.
 
@@ -213,14 +215,14 @@ 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"
         with contextlib.suppress(FileNotFoundError):
             tabs_js.unlink()  # When python 3.7 deprecated, use 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

@@ -149,6 +149,9 @@ exclude_lines = [
   "raise NotImplementedError",
   "if __name__ == .__main__.:",
   "def parse_args",
+  "from __future__ import annotations",
+  "if TYPE_CHECKING:",
+  "if t.TYPE_CHECKING:",
 ]
 
 [tool.mypy]
@@ -192,16 +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 = [
   "tmuxp",
 ]
 combine-as-imports = true
+required-imports = [
+  "from __future__ import annotations",
+]
 
 [tool.ruff.lint.pydocstyle]
 convention = "numpy"

src/tmuxp/__about__.py

@@ -1,5 +1,7 @@
 """Metadata for tmuxp package."""
 
+from __future__ import annotations
+
 __title__ = "tmuxp"
 __package_name__ = "tmuxp"
 __version__ = "1.50.1"

src/tmuxp/__init__.py

@@ -5,6 +5,8 @@
 :license: MIT, see LICENSE for details
 """
 
+from __future__ import annotations
+
 from . import cli, util
 from .__about__ import (
     __author__,

src/tmuxp/_internal/config_reader.py

@@ -1,5 +1,7 @@
 """Configuration parser for YAML and JSON files."""
 
+from __future__ import annotations
+
 import json
 import pathlib
 import typing as t
@@ -24,11 +26,11 @@ class ConfigReader:
     '{\n  "session_name": "my session"\n}'
     """
 
-    def __init__(self, content: "RawConfigData") -> None:
+    def __init__(self, content: RawConfigData) -> None:
         self.content = content
 
     @staticmethod
-    def _load(fmt: "FormatLiteral", content: str) -> dict[str, t.Any]:
+    def _load(fmt: FormatLiteral, content: str) -> dict[str, t.Any]:
         """Load raw config data and directly return it.
 
         >>> ConfigReader._load("json", '{ "session_name": "my session" }')
@@ -51,7 +53,7 @@ def _load(fmt: "FormatLiteral", content: str) -> dict[str, t.Any]:
         raise NotImplementedError(msg)
 
     @classmethod
-    def load(cls, fmt: "FormatLiteral", content: str) -> "ConfigReader":
+    def load(cls, fmt: FormatLiteral, content: str) -> ConfigReader:
         """Load raw config data into a ConfigReader instance (to dump later).
 
         >>> cfg = ConfigReader.load("json", '{ "session_name": "my session" }')
@@ -120,7 +122,7 @@ def _from_file(cls, path: pathlib.Path) -> dict[str, t.Any]:
         )
 
     @classmethod
-    def from_file(cls, path: pathlib.Path) -> "ConfigReader":
+    def from_file(cls, path: pathlib.Path) -> ConfigReader:
         r"""Load data from file path.
 
         **YAML file**
@@ -161,8 +163,8 @@ def from_file(cls, path: pathlib.Path) -> "ConfigReader":
 
     @staticmethod
     def _dump(
-        fmt: "FormatLiteral",
-        content: "RawConfigData",
+        fmt: FormatLiteral,
+        content: RawConfigData,
         indent: int = 2,
         **kwargs: t.Any,
     ) -> str:
@@ -189,7 +191,7 @@ def _dump(
         msg = f"{fmt} not supported in config"
         raise NotImplementedError(msg)
 
-    def dump(self, fmt: "FormatLiteral", indent: int = 2, **kwargs: t.Any) -> str:
+    def dump(self, fmt: FormatLiteral, indent: int = 2, **kwargs: t.Any) -> str:
         r"""Dump via ConfigReader instance.
 
         >>> cfg = ConfigReader({ "session_name": "my session" })

src/tmuxp/_internal/types.py

@@ -10,6 +10,8 @@
 ...
 """
 
+from __future__ import annotations
+
 from typing_extensions import NotRequired, TypedDict
 
 

src/tmuxp/cli/__init__.py

@@ -1,9 +1,10 @@
 """CLI utilities for tmuxp."""
 
+from __future__ import annotations
+
 import argparse
 import logging
 import os
-import pathlib
 import sys
 import typing as t
 
@@ -32,6 +33,8 @@
 logger = logging.getLogger(__name__)
 
 if t.TYPE_CHECKING:
+    import pathlib
+
     from typing_extensions import TypeAlias
 
     CLIVerbosity: TypeAlias = t.Literal["DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"]
@@ -109,16 +112,16 @@ def create_parser() -> argparse.ArgumentParser:
 class CLINamespace(argparse.Namespace):
     """Typed :class:`argparse.Namespace` for tmuxp root-level CLI."""
 
-    log_level: "CLIVerbosity"
-    subparser_name: "CLISubparserName"
-    import_subparser_name: t.Optional["CLIImportSubparserName"]
+    log_level: CLIVerbosity
+    subparser_name: CLISubparserName
+    import_subparser_name: CLIImportSubparserName | None
     version: bool
 
 
 ns = CLINamespace()
 
 
-def cli(_args: t.Optional[list[str]] = None) -> None:
+def cli(_args: list[str] | None = None) -> None:
     """Manage tmux sessions.
 
     Pass the "--help" argument to any command to see detailed help.

src/tmuxp/cli/convert.py

@@ -1,6 +1,7 @@
 """CLI for ``tmuxp convert`` subcommand."""
 
-import argparse
+from __future__ import annotations
+
 import locale
 import os
 import pathlib
@@ -13,6 +14,8 @@
 from .utils import prompt_yes_no
 
 if t.TYPE_CHECKING:
+    import argparse
+
     AllowedFileTypes = t.Literal["json", "yaml"]
 
 
@@ -53,9 +56,9 @@ def __init__(self, ext: str, *args: object, **kwargs: object) -> None:
 
 
 def command_convert(
-    workspace_file: t.Union[str, pathlib.Path],
+    workspace_file: str | pathlib.Path,
     answer_yes: bool,
-    parser: t.Optional[argparse.ArgumentParser] = None,
+    parser: argparse.ArgumentParser | None = None,
 ) -> None:
     """Entrypoint for ``tmuxp convert`` convert a tmuxp config between JSON and YAML."""
     workspace_file = find_workspace_file(
@@ -95,4 +98,3 @@ def command_convert(
     if answer_yes:
         with open(newfile, "w", encoding=locale.getpreferredencoding(False)) as buf:
             buf.write(new_workspace)
-        print(f"New workspace file saved to <{newfile}>.")

src/tmuxp/cli/debug_info.py

@@ -1,6 +1,7 @@
 """CLI for ``tmuxp debug-info`` subcommand."""
 
-import argparse
+from __future__ import annotations
+
 import os
 import pathlib
 import platform
@@ -16,6 +17,9 @@
 
 from .utils import tmuxp_echo
 
+if t.TYPE_CHECKING:
+    import argparse
+
 tmuxp_path = pathlib.Path(__file__).parent.parent
 
 
@@ -27,7 +31,7 @@ def create_debug_info_subparser(
 
 
 def command_debug_info(
-    parser: t.Optional[argparse.ArgumentParser] = None,
+    parser: argparse.ArgumentParser | None = None,
 ) -> None:
     """Entrypoint for ``tmuxp debug-info`` to print debug info to submit with issues."""
 

src/tmuxp/cli/edit.py

@@ -1,13 +1,17 @@
 """CLI for ``tmuxp edit`` subcommand."""
 
-import argparse
+from __future__ import annotations
+
 import os
-import pathlib
 import subprocess
 import typing as t
 
 from tmuxp.workspace.finders import find_workspace_file
 
+if t.TYPE_CHECKING:
+    import argparse
+    import pathlib
+
 
 def create_edit_subparser(
     parser: argparse.ArgumentParser,
@@ -23,8 +27,8 @@ def create_edit_subparser(
 
 
 def command_edit(
-    workspace_file: t.Union[str, pathlib.Path],
-    parser: t.Optional[argparse.ArgumentParser] = None,
+    workspace_file: str | pathlib.Path,
+    parser: argparse.ArgumentParser | None = None,
 ) -> None:
     """Entrypoint for ``tmuxp edit``, open tmuxp workspace file in system editor."""
     workspace_file = find_workspace_file(workspace_file)