feat: drop 3.9 (#1057)

* feat: drop 3.9

Signed-off-by: Henry Schreiner <[email protected]>

* style: pre-commit fixes

* fix: revert strenum change

Signed-off-by: Henry Schreiner <[email protected]>

* style: pre-commit fixes

* Update Python version for Windows environment

---------

Signed-off-by: Henry Schreiner <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: henryiii

.github/workflows/examples.yml

@@ -21,7 +21,7 @@ jobs:
           submodules: true
       - uses: actions/setup-python@v6
         with:
-          python-version: "3.9"
+          python-version: "3.10"
       - uses: astral-sh/setup-uv@v7
       - name: Build and install kernel
         run: uv run --group examples -m ipykernel install --user --name boost-hist

.github/workflows/tests.yml

@@ -59,7 +59,7 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - python-version: "3.9"
+          - python-version: "3.10"
             cmake-extras: "-DCMAKE_CXX_STANDARD=17"
           - python-version: "3.11"
           - python-version: "3.13t"
@@ -111,7 +111,7 @@ jobs:
           - os: ubuntu-24.04-arm
             only: cp313-manylinux_aarch64
           - os: windows-latest
-            only: cp39-win32
+            only: cp310-win32
           - os: windows-latest
             only: cp313-win_amd64
           - os: macos-13

.pre-commit-config.yaml

@@ -47,7 +47,7 @@ repos:
     hooks:
       - id: mypy
         files: ^src
-        additional_dependencies: [numpy~=2.3.0, pytest, uhi]
+        additional_dependencies: [numpy~=2.2.0, pytest, uhi]
 
   - repo: https://github.com/codespell-project/codespell
     rev: v2.4.1

README.md

@@ -179,11 +179,12 @@ python3 -m pip install boost-histogram
 ```
 
 All the normal best-practices for Python apply; Pip should not be very old (Pip
-9 is very old), you should be in a virtual environment, etc. Python 3.9+ is
+9 is very old), you should be in a virtual environment, etc. Python 3.10+ is
 required; for older versions of Python (3.5 and 2.7), `0.13` will be installed
 instead, which is API equivalent to 1.0, but will not be gaining new features.
 1.3.x was the last series to support Python 3.6. 1.4.x was the last series to
-support Python 3.7. 1.5.x was the last series to support Python 3.8.
+support Python 3.7. 1.5.x was the last series to support Python 3.8. 1.6.x was
+the last to support Python 3.9.
 
 #### Binaries available:
 
@@ -192,17 +193,18 @@ when you run the above command on a supported platform. Wheels are produced usin
 [cibuildwheel](https://cibuildwheel.readthedocs.io/en/stable/); all common
 platforms have wheels provided in boost-histogram:
 
-| System        | Arch   | Python versions                    | PyPy versions |
-| ------------- | ------ | ---------------------------------- | ------------- |
-| manylinux2014 | 64-bit | 3.9, 3.10, 3.11, 3.12, 3.13, 3.13t | 3.9, 3.10     |
-| manylinux2014 | ARM64  | 3.9, 3.10, 3.11, 3.12, 3.13, 3.13t | 3.9, 3.10     |
-| musllinux_1_1 | 64-bit | 3.9, 3.10, 3.11, 3.12, 3.13, 3.13t |               |
-| macOS         | 64-bit | 3.9, 3.10, 3.11, 3.12, 3.13, 3.13t | 3.9, 3.10     |
-| macOS         | Arm64  | 3.9, 3.10, 3.11, 3.12, 3.13, 3.13t | 3.9, 3.10     |
-| Windows       | 32-bit | 3.9, 3.10, 3.11, 3.12, 3.13, 3.13t |               |
-| Windows       | 64-bit | 3.9, 3.10, 3.11, 3.12, 3.13, 3.13t | 3.9, 3.10     |
-
-PowerPC or IBM-Z wheels are not provided but are available on request.
+| System    | Arch   | Python versions                            | PyPy versions |
+| --------- | ------ | ------------------------------------------ | ------------- |
+| manylinux | 64-bit | 3.10, 3.11, 3.12, 3.13, 3.13t, 3.14, 3.14t | 3.11          |
+| manylinux | ARM64  | 3.10, 3.11, 3.12, 3.13, 3.13t, 3.14, 3.14t | 3.11          |
+| musllinux | 64-bit | 3.10, 3.11, 3.12, 3.13, 3.13t, 3.14, 3.14t |               |
+| macOS     | 64-bit | 3.10, 3.11, 3.12, 3.13, 3.13t, 3.14, 3.14t | 3.11          |
+| macOS     | Arm64  | 3.10, 3.11, 3.12, 3.13, 3.13t, 3.14, 3.14t | 3.11          |
+| Windows   | 32-bit | 3.10, 3.11, 3.12, 3.13, 3.13t, 3.14, 3.14t |               |
+| Windows   | 64-bit | 3.10, 3.11, 3.12, 3.13, 3.13t, 3.14, 3.14t | 3.11          |
+| Windows   | ARM64  | 3.11, 3.12, 3.13, 3.13t, 3.14, 3.14t       |               |
+
+PowerPC, IBM-Z, and RISC-V wheels are not provided but are available on request.
 
 If you are on a Linux system that is not part of the "many" in manylinux or musl in musllinux, such as ClearLinux, building from source is usually fine, since the compilers on those systems are often quite new. It will just take longer to install when it is using the sdist instead of a wheel. All dependencies are header-only and included.
 

examples/README.md

@@ -1,6 +1,6 @@
 # Boost Histogram examples
 
-The examples require Python 3.9. It is left as an exercise for the reader to
+The examples require Python 3.10. It is left as an exercise for the reader to
 convert back to older versions if they so desire.
 
 ### Setup

notebooks/xarray.ipynb

@@ -178,7 +178,7 @@
     "        name=\"_\".join(a.name for a in args) + \"_histogram\",\n",
     "        coords=[\n",
     "            (f\"{a.name}_bin\", arr.flatten(), a.attrs)\n",
-    "            for a, arr in zip(args, h.axes.centers)\n",
+    "            for a, arr in zip(args, h.axes.centers, strict=False)\n",
     "        ],\n",
     "    )"
    ]
@@ -270,7 +270,7 @@
     "        name=\"_\".join(a.name for a in args) + \"_histogram\",\n",
     "        coords=[\n",
     "            (f\"{a.name}_bin\", arr.flatten(), a.attrs)\n",
-    "            for a, arr in zip(args, h.axes.centers)\n",
+    "            for a, arr in zip(args, h.axes.centers, strict=False)\n",
     "        ],\n",
     "    )"
    ]

pyproject.toml

@@ -7,7 +7,7 @@ name = "boost-histogram"
 dynamic = ["version"]
 description = "The Boost::Histogram Python wrapper."
 readme = "README.md"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 authors = [
     { name = "Hans Dembinski", email = "[email protected]" },
     { name = "Henry Schreiner", email = "[email protected]" },
@@ -37,7 +37,6 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
     "Programming Language :: Python :: 3.14",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: Free Threading :: 3 - Stable",
     "Programming Language :: Python :: Free Threading",
     "Programming Language :: Python :: Implementation :: CPython",
@@ -158,7 +157,7 @@ required_plugins = ["pytest-benchmark"]
 log_cli_level = "DEBUG"
 
 [tool.mypy]
-python_version = "3.9"
+python_version = "3.10"
 files = ["src"]
 strict = true
 enable_error_code = ["ignore-without-code", "redundant-expr", "truthy-bool"]
@@ -181,8 +180,8 @@ test-command = "python -m pytest -n auto --benchmark-disable tests"
 test-sources = ["pyproject.toml", "tests"]
 test-environment.CI = "1"  # Hypothosis needs this on GraalPy
 test-skip = [
-  "cp3{9,10}-win_arm64",
-  "cp3{9,10}-musllinux_*",
+  "cp310-win_arm64",
+  "cp310-musllinux_*",
   "pp310-manylinux_aarch64",
   "pp310-macosx_arm64",
   "cp31*-musllinux_*", # Threading test crashes
@@ -228,7 +227,7 @@ environment.UV_INDEX_STRATEGY = "unsafe-best-match"
 test-command = "pytest --benchmark-disable tests"
 
 [tool.pylint]
-py-version = "3.9"
+py-version = "3.10"
 ignore-patterns = ['.*\.pyi']
 ignore = "version.py"
 extension-pkg-allow-list = ["boost_histogram._core"]

src/boost_histogram/_core/axis/transform.pyi

@@ -1,4 +1,5 @@
-from typing import Any, Callable
+from collections.abc import Callable
+from typing import Any
 
 from typing_extensions import Self
 

src/boost_histogram/_utils.py

@@ -1,10 +1,8 @@
 from __future__ import annotations
 
-import itertools
-import sys
 import typing
-from collections.abc import Iterator
-from typing import Any, Callable, ClassVar, Protocol, TypeVar
+from collections.abc import Callable, Iterator
+from typing import ClassVar, Protocol, TypeVar
 
 import boost_histogram
 
@@ -165,16 +163,3 @@ def _walk_subclasses(cls: type[object]) -> Iterator[type[object]]:
         # user subclasses to work
         yield from _walk_subclasses(base)
         yield base
-
-
-def zip_strict(*args: Any) -> Iterator[tuple[Any, ...]]:
-    if sys.version_info >= (3, 10):
-        yield from zip(*args, strict=True)
-        return
-
-    marker = object()
-    for each in itertools.zip_longest(*args, fillvalue=marker):
-        for val in each:
-            if val is marker:
-                raise ValueError("zip() arguments are not the same length")
-        yield each

src/boost_histogram/axis/__init__.py

@@ -1,17 +1,15 @@
 from __future__ import annotations
 
 import copy
-from collections.abc import Iterable, Iterator
+from collections.abc import Callable, Iterable, Iterator
 from dataclasses import dataclass
 from functools import partial
 from typing import (
     Any,
-    Callable,
     ClassVar,
     Literal,
     TypedDict,
     TypeVar,
-    Union,
 )
 
 import numpy as np  # pylint: disable=unused-import
@@ -20,7 +18,7 @@
 
 from .._compat.typing import Self
 from .._core import axis as ca
-from .._utils import cast, register, zip_strict
+from .._utils import cast, register
 from . import transform
 from .transform import AxisTransform
 
@@ -59,7 +57,7 @@ def _opts(**kwargs: bool) -> set[str]:
     return {k for k, v in kwargs.items() if v}
 
 
-AxCallOrInt = Union[int, Callable[["Axis"], int]]
+AxCallOrInt = int | Callable[["Axis"], int]
 
 
 @dataclass(order=True, frozen=True)
@@ -287,21 +285,21 @@ def __getitem__(self, i: AxCallOrInt) -> int | str | tuple[float, float]:
 
     @property
     def edges(self) -> np.typing.NDArray[Any]:
-        return self._ax.edges
+        return self._ax.edges  # type: ignore[no-any-return]
 
     @property
     def centers(self) -> np.typing.NDArray[Any]:
         """
         An array of bin centers.
         """
-        return self._ax.centers
+        return self._ax.centers  # type: ignore[no-any-return]
 
     @property
     def widths(self) -> np.typing.NDArray[Any]:
         """
         An array of bin widths.
         """
-        return self._ax.widths
+        return self._ax.widths  # type: ignore[no-any-return]
 
 
 # Contains all common methods and properties for Regular axes
@@ -910,7 +908,7 @@ def __setattr__(self, attr: str, values: Any) -> None:
         try:
             super().__setattr__(attr, values)
         except AttributeError:
-            for s, v in zip_strict(self, values):
+            for s, v in zip(self, values, strict=True):
                 s.__setattr__(attr, v)
 
     value.__doc__ = Axis.value.__doc__