Switch to PEP517 build with Hatch

.github/workflows/ci.yml

@@ -51,7 +51,7 @@ jobs:
         python-version: ${{ matrix.python-version }}
         allow-prereleases: true
         cache: "pip"
-        cache-dependency-path: "**/setup.py"
+        cache-dependency-path: "**/pyproject.toml"
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip setuptools wheel
@@ -76,7 +76,7 @@ jobs:
         with:
           python-version: "3.13"
           cache: "pip"
-          cache-dependency-path: "**/setup.py"
+          cache-dependency-path: "**/pyproject.toml"
       - run: pip install build -e .
       - run: make import-cldr
       - run: python -m build

babel/core.py

@@ -56,12 +56,13 @@
 
 
 def _raise_no_data_error():
-    raise RuntimeError('The babel data files are not available. '
-                       'This usually happens because you are using '
-                       'a source checkout from Babel and you did '
-                       'not build the data files.  Just make sure '
-                       'to run "python setup.py import_cldr" before '
-                       'installing the library.')
+    raise RuntimeError(
+        'The babel data files are not available. '
+        'This usually happens because you are using '
+        'a source checkout from Babel and you did '
+        'not build the data files. Please see the '
+        'README.rst file for more information.',
+    )
 
 
 def get_global(key: _GLOBAL_KEY) -> Mapping[str, Any]:

conftest.py

@@ -4,7 +4,6 @@
 
 collect_ignore = [
     'babel/messages/setuptools_frontend.py',
-    'setup.py',
     'tests/messages/data',
 ]
 babel_path = Path(__file__).parent / 'babel'

docs/installation.rst

@@ -83,17 +83,17 @@ Get the git checkout in a new virtualenv and run in development mode::
     New python executable in venv/bin/python
     Installing distribute............done.
     $ . venv/bin/activate
-    $ python setup.py import_cldr
+    $ make import-cldr
     $ pip install --editable .
     ...
     Finished processing dependencies for Babel
 
-Make sure to not forget about the ``import_cldr`` step because otherwise
+Make sure to not forget about the CLDR import step because otherwise
 you will be missing the locale data.
 The custom setup command will download the most appropriate CLDR release from the
 official website and convert it for Babel.
 
 This will pull also in the dependencies and activate the git head as the
 current version inside the virtualenv.  Then all you have to do is run
 ``git pull origin`` to update to the latest version.  If the CLDR data
-changes you will have to re-run ``python setup.py import_cldr``.
+changes you will have to re-run ``make import-cldr``.

hatch_build.py

@@ -0,0 +1,33 @@
+import os
+import tarfile
+import zipfile
+
+from hatchling.builders.hooks.plugin.interface import BuildHookInterface
+
+DAT_MESSAGE = """
+======
+Package should contain multiple .dat files.
+* Make sure you've imported the CLDR data; `make import-cldr`.
+------
+To skip this check, set the environment variable BABEL_NO_CHECK_BUILD=1
+======
+""".strip()
+
+
+def check_babel_artifact(artifact_path: str):
+    if artifact_path.endswith(".whl"):
+        with zipfile.ZipFile(artifact_path) as whl:
+            filelist = whl.namelist()
+    elif artifact_path.endswith(".tar.gz"):
+        with tarfile.open(artifact_path) as tar:
+            filelist = tar.getnames()
+    if len([f.endswith(".dat") for f in filelist]) < 10:
+        raise ValueError(DAT_MESSAGE)
+
+
+class CustomBuildHook(BuildHookInterface):
+    def finalize(self, version, build_data, artifact_path):
+        if version == "editable":
+            return
+        if not os.environ.get("BABEL_NO_CHECK_BUILD"):
+            check_babel_artifact(artifact_path)

pyproject.toml

@@ -1,3 +1,116 @@
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[project]
+name = "babel"
+dynamic = ["version"]
+description = "Internationalization utilities"
+readme = "README.rst"
+license = "BSD-3-Clause"
+license-files = ["LICENSE"]
+requires-python = ">=3.8"
+authors = [
+    { name = "Armin Ronacher", email = "[email protected]" },
+]
+maintainers = [
+    { name = "Aarni Koskela", email = "[email protected]" },
+]
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Environment :: Web Environment",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: BSD License",
+    "Operating System :: OS Independent",
+    "Programming Language :: Python :: 3 :: Only",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: Implementation :: CPython",
+    "Programming Language :: Python :: Implementation :: PyPy",
+    "Programming Language :: Python",
+    "Topic :: Software Development :: Internationalization",
+    "Topic :: Software Development :: Libraries :: Python Modules",
+]
+
+dependencies = [
+    # This version identifier is currently necessary as
+    # pytz otherwise does not install on pip 1.4 or higher.
+    # Python 3.9 and later include zoneinfo which replaces pytz.
+    'pytz>=2015.7; python_version<"3.9"',
+]
+
+[project.optional-dependencies]
+# TODO: use a `dev` dependency group instead
+dev = [
+    "backports.zoneinfo; python_version<\"3.9\"",
+    "freezegun~=1.0",
+    "jinja2>=3.0",
+    "pytest-cov",
+    "pytest>=6.0",
+    "pytz",
+    "setuptools",
+    "tzdata;sys_platform == 'win32'",
+]
+
+[project.urls]
+Homepage = "https://babel.pocoo.org/"
+Source = "https://github.com/python-babel/babel"
+
+[tool.hatch.version]
+path = "babel/__init__.py"
+
+[tool.hatch.build.hooks.custom]
+
+[tool.hatch.build.targets.sdist]
+include = [
+    "/Makefile",
+    "/babel",
+    "/docs",
+    "/scripts",
+    "/tests",
+    "AUTHORS",
+    "CHANGES.rst",
+    "conftest.py",
+    "tox.ini",
+]
+
+[tool.hatch.build.targets.wheel]
+include = [
+    "/babel",
+]
+artifacts = [
+    "**.dat",
+]
+exclude = [
+    "/babel/locale-data/.gitignore",
+]
+
+[project.scripts]
+pybabel = "babel.messages.frontend:main"
+
+[project.entry-points."distutils.commands"]
+compile_catalog = "babel.messages.setuptools_frontend:compile_catalog"
+extract_messages = "babel.messages.setuptools_frontend:extract_messages"
+init_catalog = "babel.messages.setuptools_frontend:init_catalog"
+update_catalog = "babel.messages.setuptools_frontend:update_catalog"
+
+[project.entry-points."distutils.setup_keywords"]
+message_extractors = "babel.messages.setuptools_frontend:check_message_extractors"
+
+[project.entry-points."babel.checkers"]
+num_plurals = "babel.messages.checkers:num_plurals"
+python_format = "babel.messages.checkers:python_format"
+
+[project.entry-points."babel.extractors"]
+ignore = "babel.messages.extract:extract_nothing"
+python = "babel.messages.extract:extract_python"
+javascript = "babel.messages.extract:extract_javascript"
+
 [tool.ruff]
 target-version = "py38"
 extend-exclude = [