feat: lower minimum Python from 3.14 to 3.12

Three 3.14-only constructs prevented importing on 3.12/3.13:

- unparenthesized `except A, B:` (PEP 758) -> parenthesized (3 sites)
- eagerly-evaluated annotations (PEP 649) -> `from __future__ import annotations` in the 31 modules that need it
- zero-arg `super()` in a `slots=True` dataclass (CPython gh-90562, fixed in 3.13) -> drop `slots=True` on DatasetSchema

CI matrix now 3.12/3.13/3.14; mypy pinned to `python_version=3.12`.

Author: tzilio-cls

.github/workflows/ci.yaml

@@ -19,7 +19,7 @@ jobs:
       fail-fast: false
       max-parallel: 5
       matrix:
-        python-version: ['3.14']
+        python-version: ['3.12', '3.13', '3.14']
     steps:
     - name: Checkout
       uses: actions/checkout@v4
@@ -75,7 +75,7 @@ jobs:
           channels:
             - conda-forge
         create-args: |
-          python=3.14
+          python=3.12
         environment-name: ZCollection
         environment-file: conda/environment.yml
 

.github/workflows/docs.yaml

@@ -54,7 +54,7 @@ jobs:
             channels:
               - conda-forge
           create-args: |
-            python=3.14
+            python=3.12
           environment-name: ZCollection
           environment-file: conda/environment.yml
 

.github/workflows/pre-commit.yml

@@ -11,5 +11,5 @@ jobs:
     - uses: actions/checkout@v4
     - uses: actions/setup-python@v5
       with:
-        python-version: '3.14'
+        python-version: '3.12'
     - uses: pre-commit/action@v3.0.1

.github/workflows/pypipublish.yaml

@@ -30,7 +30,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: '3.14'
+          python-version: '3.12'
 
       - name: Install build tooling
         run: |

.pre-commit-config.yaml

@@ -17,7 +17,7 @@ repos:
     rev: "v3.21.2"
     hooks:
     - id: pyupgrade
-      args: [--py314-plus]
+      args: [--py312-plus]
   - repo: https://github.com/astral-sh/ruff-pre-commit
     rev: v0.15.12
     hooks:

conda/environment.yml

@@ -2,8 +2,8 @@ name: ZCollection
 channels:
   - conda-forge
 dependencies:
-  # Python (matches setup.cfg `python_requires = >=3.14`)
-  - python >=3.14
+  # Python (matches setup.cfg `python_requires = >=3.12`)
+  - python >=3.12
   # Runtime
   - dask-core >=2022.8.0
   - distributed

docs/source/install.rst

@@ -8,7 +8,7 @@ compatibility runtime.
 Requirements
 ------------
 
-- Python **3.14** or later
+- Python **3.12** or later
 - `zarr <https://zarr.readthedocs.io/>`_ ≥ 3.1.6
 - `numpy <https://numpy.org/>`_ ≥ 1.20
 - `numcodecs <https://numcodecs.readthedocs.io/>`_ ≥ 0.13

examples/ex_netcdf_to_zcollection.py

@@ -98,6 +98,8 @@
 which xarray cannot do natively without an explicit ``group=`` argument.
 """
 
+from __future__ import annotations
+
 from typing import TYPE_CHECKING, Any
 import argparse
 from datetime import datetime

pyproject.toml

@@ -17,7 +17,7 @@ __version__ = "{version}"
 
 
 [tool.ruff]
-target-version = "py314"
+target-version = "py312"
 line-length = 80
 
 [tool.ruff.lint.pycodestyle]

setup.cfg

@@ -8,6 +8,8 @@ classifiers =
     Operating System :: MacOS
     Operating System :: Microsoft :: Windows
     Operating System :: POSIX
+    Programming Language :: Python :: 3.12
+    Programming Language :: Python :: 3.13
     Programming Language :: Python :: 3.14
     Topic :: Scientific/Engineering :: Physics
 description = Zarr Collection
@@ -34,7 +36,7 @@ install_requires =
 package_dir =
     = .
 packages = find:
-python_requires = >=3.14
+python_requires = >=3.12
 zip_safe = False
 
 [options.extras_require]
@@ -78,3 +80,4 @@ ignore =
 [mypy]
 ignore_missing_imports=True
 exclude=tests
+python_version=3.12