Support adding the classifier for the current Python prerelease (#162)

Co-authored-by: Bernát Gábor <bgabor8@bloomberg.net>

src/pyproject_fmt/cli.py

@@ -11,8 +11,10 @@
 from pathlib import Path
 from typing import Sequence
 
+from packaging.version import Version
+
 from ._version import __version__
-from .formatter.config import DEFAULT_INDENT, Config
+from .formatter.config import DEFAULT_INDENT, DEFAULT_MAX_SUPPORTED_PYTHON, Config
 
 
 class PyProjectFmtNamespace(Namespace):
@@ -23,6 +25,7 @@ class PyProjectFmtNamespace(Namespace):
     indent: int
     check: bool
     keep_full_version: bool
+    max_supported_python: Version
 
     @property
     def configs(self) -> list[Config]:
@@ -33,6 +36,7 @@ def configs(self) -> list[Config]:
                 toml=toml.read_text(encoding="utf-8"),
                 indent=self.indent,
                 keep_full_version=self.keep_full_version,
+                max_supported_python=self.max_supported_python,
             )
             for toml in self.inputs
         ]
@@ -88,6 +92,12 @@ def _build_cli() -> ArgumentParser:
         default=DEFAULT_INDENT,
         help="number of spaces to indent",
     )
+    parser.add_argument(
+        "--max-supported-python",
+        type=Version,
+        default=DEFAULT_MAX_SUPPORTED_PYTHON,
+        help="latest Python version the project supports (e.g. 3.13)",
+    )
     msg = "pyproject.toml file(s) to format"
     parser.add_argument("inputs", nargs="+", type=pyproject_toml_path_creator, help=msg)
     return parser

src/pyproject_fmt/formatter/config.py

@@ -1,15 +1,18 @@
 """Defines configuration for the formatter."""
 from __future__ import annotations
 
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from typing import TYPE_CHECKING
 
+from packaging.version import Version
+
 if TYPE_CHECKING:
     from pathlib import Path
     from typing import Final
 
 
 DEFAULT_INDENT: Final[int] = 2  #: default indentation level
+DEFAULT_MAX_SUPPORTED_PYTHON: Final[str] = "3.12"  #: default maximum supported Python version
 
 
 @dataclass(frozen=True)
@@ -20,9 +23,11 @@ class Config:
     toml: str  #: the text to format
     indent: int = DEFAULT_INDENT  #: indentation to apply
     keep_full_version: bool = False
+    max_supported_python: Version = field(default_factory=lambda: Version(DEFAULT_MAX_SUPPORTED_PYTHON))
 
 
 __all__ = [
     "Config",
     "DEFAULT_INDENT",
+    "DEFAULT_MAX_SUPPORTED_PYTHON",
 ]

src/pyproject_fmt/formatter/project.py

@@ -20,7 +20,6 @@
     from .config import Config
 
 _PY_MIN_VERSION: int = 7
-_PY_MAX_VERSION: int = 12
 
 
 def fmt_project(parsed: TOMLDocument, conf: Config) -> None:  # noqa: C901
@@ -45,7 +44,7 @@ def fmt_project(parsed: TOMLDocument, conf: Config) -> None:  # noqa: C901
     sorted_array(cast(Optional[Array], project.get("dynamic")), indent=conf.indent)
 
     if "requires-python" in project:
-        _add_py_classifiers(project)
+        _add_py_classifiers(project, py_max_version=conf.max_supported_python)
 
     sorted_array(cast(Optional[Array], project.get("classifiers")), indent=conf.indent, custom_sort="natsort")
 
@@ -105,11 +104,11 @@ def fmt_project(parsed: TOMLDocument, conf: Config) -> None:  # noqa: C901
     ensure_newline_at_end(project)
 
 
-def _add_py_classifiers(project: Table) -> None:
+def _add_py_classifiers(project: Table, *, py_max_version: Version) -> None:
     specifiers = SpecifierSet(project.get("requires-python", f">=3.{_PY_MIN_VERSION}"))
 
     min_version = _get_min_version_classifier(specifiers)
-    max_version = _get_max_version_classifier(specifiers)
+    max_version = _get_max_version_classifier(specifiers, py_max_version=py_max_version)
 
     allowed_versions = list(specifiers.filter(f"3.{v}" for v in range(min_version, max_version + 1)))
 
@@ -142,18 +141,19 @@ def _get_min_version_classifier(specifiers: SpecifierSet) -> int:
             min_version.append(Version(specifier.version).minor)
         if specifier.operator == ">":
             min_version.append(Version(specifier.version).minor + 1)
-    return min(min_version) if min_version else _PY_MIN_VERSION
+    return min(min_version, default=_PY_MIN_VERSION)
 
 
-def _get_max_version_classifier(specifiers: SpecifierSet) -> int:
+def _get_max_version_classifier(specifiers: SpecifierSet, *, py_max_version: Version) -> int:
     max_version: list[int] = []
 
     for specifier in specifiers:
         if specifier.operator == "<=":
             max_version.append(Version(specifier.version).minor)
         if specifier.operator == "<":
             max_version.append(Version(specifier.version).minor - 1)
-    return max(max_version) if max_version else (_get_max_version_tox() or _PY_MAX_VERSION)
+
+    return max(max_version) if max_version else (_get_max_version_tox() or py_max_version.minor)
 
 
 def _get_max_version_tox() -> int | None:

tests/formatter/test_project.py

@@ -6,6 +6,7 @@
 from typing import TYPE_CHECKING
 
 import pytest
+from packaging.version import Version
 
 from pyproject_fmt.formatter.config import Config
 from pyproject_fmt.formatter.project import fmt_project
@@ -373,6 +374,40 @@ def test_classifier_two_upper_bounds(fmt: Fmt) -> None:
     fmt(fmt_project, start, expected)
 
 
+def test_classifier_prerelease(fmt: Fmt) -> None:
+    txt = """
+    [project]
+    requires-python = ">=3.10"
+    classifiers = [
+      "Programming Language :: Python :: 3 :: Only",
+      "Programming Language :: Python :: 3.9",
+      "Programming Language :: Python :: 3.10",
+      "Programming Language :: Python :: 3.11",
+      "Programming Language :: Python :: 3.12",
+    ]
+    """
+    expected = """
+    [project]
+    requires-python = ">=3.10"
+    classifiers = [
+      "Programming Language :: Python :: 3 :: Only",
+      "Programming Language :: Python :: 3.10",
+      "Programming Language :: Python :: 3.11",
+      "Programming Language :: Python :: 3.12",
+      "Programming Language :: Python :: 3.13",
+      "Programming Language :: Python :: 3.14",
+      "Programming Language :: Python :: 3.15",
+    ]
+    """
+    config = Config(
+        pyproject_toml=Path(),
+        toml=dedent(txt),
+        max_supported_python=Version("3.15"),
+    )
+
+    fmt(fmt_project, config, expected)
+
+
 def test_classifier_gt_tox(fmt: Fmt, tmp_path: Path) -> None:
     (tmp_path / "tox.ini").write_text("[tox]\nenv_list = py{311,312}-{magic}")
     start = """