ENH: do not rely on packaging module for generating wheel tags

The generated tags are tested checking against what the packaging
module generates. This should ensure that the two implementations will
not diverge.

meson.build

@@ -11,6 +11,7 @@ py.install_sources(
   'mesonpy/__init__.py',
   'mesonpy/_compat.py',
   'mesonpy/_elf.py',
+  'mesonpy/_tags.py',
   'mesonpy/_util.py',
   subdir: 'mesonpy',
 )

mesonpy/__init__.py

@@ -36,8 +36,6 @@
     Union
 )
 
-import packaging.tags
-
 
 if sys.version_info < (3, 11):
     import tomli as tomllib
@@ -46,6 +44,7 @@
 
 import mesonpy._compat
 import mesonpy._elf
+import mesonpy._tags
 import mesonpy._util
 
 from mesonpy._compat import Iterator, Path
@@ -109,30 +108,6 @@ def _init_colors() -> Dict[str, str]:
 assert all(re.match(_EXTENSION_SUFFIX_REGEX, x) for x in _EXTENSION_SUFFIXES)
 
 
-def _adjust_manylinux_tag(platform: str) -> str:
-    # The packaging module generates overly specific platforms tags on
-    # Linux.  The platforms tags on Linux evolved over time.  Relax
-    # the platform tags to maintain compatibility with old wheel
-    # installation tools.  The relaxed platform tags match the ones
-    # generated by the wheel package.
-    # https://packaging.python.org/en/latest/specifications/platform-compatibility-tags/
-    return re.sub(r'^manylinux(1|2010|2014|_\d+_\d+)_(.*)$', r'linux_\2', platform)
-
-
-def _adjust_darwin_tag(platform: str) -> str:
-    # Override the macOS version if one is provided via the
-    # MACOS_DEPLOYMENT_TARGET environment variable.  Return it
-    # unchanged otherwise.
-    try:
-        version = tuple(map(int, os.environ.get('MACOS_DEPLOYMENT_TARGET', '').split('.')))[:2]
-    except ValueError:
-        version = None
-    if version is not None:
-        # str() to silence mypy
-        platform = str(next(packaging.tags.mac_platforms(version)))
-    return platform
-
-
 def _showwarning(
     message: Union[Warning, str],
     category: Type[Warning],
@@ -219,26 +194,17 @@ def basename(self) -> str:
         )
 
     @property
-    def tag(self) -> packaging.tags.Tag:
+    def tag(self) -> mesonpy._tags.Tag:
         """Wheel tags."""
         if self.is_pure:
-            return packaging.tags.Tag('py3', 'none', 'any')
-        # Get the most specific tag for the Python interpreter.
-        tag = next(packaging.tags.sys_tags())
-        if tag.platform.startswith('manylinux'):
-            tag = packaging.tags.Tag(tag.interpreter, tag.abi, _adjust_manylinux_tag(tag.platform))
-        elif tag.platform.startswith('darwin'):
-            tag = packaging.tags.Tag(tag.interpreter, tag.abi, _adjust_darwin_tag(tag.platform))
+            return mesonpy._tags.Tag('py3', 'none', 'any')
         if not self._has_extension_modules:
             # The wheel has platform dependent code (is not pure) but
             # does not contain any extension module (does not
             # distribute any file in {platlib}) thus use generic
             # implementation and ABI tags.
-            return packaging.tags.Tag('py3', 'none', tag.platform)
-        if self._stable_abi:
-            # All distributed extension modules use the stable ABI.
-            return packaging.tags.Tag(tag.interpreter, self._stable_abi, tag.platform)
-        return tag
+            return mesonpy._tags.Tag('py3', 'none', None)
+        return mesonpy._tags.Tag(None, self._stable_abi, None)
 
     @property
     def name(self) -> str:

mesonpy/_tags.py

@@ -0,0 +1,119 @@
+# SPDX-License-Identifier: MIT
+
+import os
+import platform
+import subprocess
+import sys
+import sysconfig
+
+from typing import Optional, Union
+
+
+# https://peps.python.org/pep-0425/#python-tag
+INTERPRETERS = {
+    'python': 'py',
+    'cpython': 'cp',
+    'pypy': 'pp',
+    'ironpython': 'ip',
+    'jython': 'jy',
+}
+
+
+def get_interpreter_tag() -> str:
+    name = sys.implementation.name
+    name = INTERPRETERS.get(name, name)
+    if name in {'cp', 'pp'}:
+        version = sys.version_info
+        return f'{name}{version[0]}{version[1]}'
+    return name
+
+
+def _get_config_var(name: str, default: Union[str, int, None] = None) -> Union[str, int, None]:
+    value = sysconfig.get_config_var(name)
+    if value is None:
+        return default
+    return value
+
+
+def _get_cpython_abi() -> str:
+    version = sys.version_info
+    debug = pymalloc = ''
+    if _get_config_var('Py_DEBUG', hasattr(sys, 'gettotalrefcount')):
+        debug = 'd'
+    if sys.version_info < (3, 8) and _get_config_var('WITH_PYMALLOC', True):
+        pymalloc = 'm'
+    return f'cp{version[0]}{version[1]}{debug}{pymalloc}'
+
+
+def get_abi_tag() -> str:
+    abi = sysconfig.get_config_var('SOABI')
+    if not abi:
+        # CPython on Windows does not have a SOABI sysconfig variable.
+        assert sys.implementation.name == 'cpython'
+        return _get_cpython_abi()
+    if abi.startswith('cpython'):
+        return 'cp' + abi.split('-')[1]
+    if abi.startswith('pypy'):
+        return '_'.join(abi.split('-')[:2])
+    return abi.replace('.', '_').replace('-', '_')
+
+
+def _get_macosx_platform_tag() -> str:
+    ver, x, arch = platform.mac_ver()
+
+    # Override the macOS version if one is provided via the
+    # MACOS_DEPLOYMENT_TARGET environment variable.  Return it
+    # unchanged otherwise.
+    try:
+        version = tuple(map(int, os.environ.get('MACOS_DEPLOYMENT_TARGET', '').split('.')))[:2]
+    except ValueError:
+        version = None
+
+    if version is None:
+        version = tuple(map(int, ver.split('.')))[:2]
+        if version == (10, 16):
+            # When built against an older macOS SDK, Python will
+            # report macOS 10.16 instead of the real version.
+            ver = subprocess.check_output(
+                [
+                    sys.executable,
+                    '-sS',
+                    '-c',
+                    'import platform; print(platform.mac_ver()[0])'
+                ],
+                env={'SYSTEM_VERSION_COMPAT': '0'},
+                universal_newlines=True)
+            version = tuple(map(int, ver.split('.')[:2]))
+
+    major, minor = version
+    if major >= 11:
+        minor = 0
+
+    if sys.maxsize <= 2**32:
+        if arch.startswith('ppc'):
+            arch = 'ppc'
+        arch = 'i386'
+
+    return f'macosx_{major}_{minor}_{arch}'
+
+
+def get_platform_tag() -> str:
+    platform = sysconfig.get_platform()
+    if platform.startswith('macosx'):
+        return _get_macosx_platform_tag()
+    if sys.maxsize <= 2**32:
+        if platform == 'linux-x86_64':
+            return 'linux_i686'
+        if platform == 'linux-aarch64':
+            return 'linux_armv7l'
+    return platform.replace('-', '_')
+
+
+class Tag:
+    def __init__(self, interpreter: Optional[str] = None, abi: Optional[str] = None, platform: Optional[str] = None):
+        self.interpreter = interpreter or get_interpreter_tag()
+        self.abi = abi or get_abi_tag()
+        self.platform = platform or get_platform_tag()
+
+    def __str__(self) -> str:
+        return f'{self.interpreter}-{self.abi}-{self.platform}'

tests/conftest.py

@@ -4,6 +4,7 @@
 import os
 import os.path
 import pathlib
+import re
 import shutil
 import tempfile
 
@@ -15,6 +16,24 @@
 import mesonpy
 
 
+def adjust_packaging_platform_tag(platform: str) -> str:
+    # The packaging module generates overly specific platforms tags on
+    # Linux.  The platforms tags on Linux evolved over time.
+    # meson-python uses more relaxed platform tags to maintain
+    # compatibility with old wheel installation tools.  The relaxed
+    # platform tags match the ones generated by the wheel package.
+    # https://packaging.python.org/en/latest/specifications/platform-compatibility-tags/
+    platform = re.sub(r'^manylinux(1|2010|2014|_\d+_\d+)_(.*)$', r'linux_\2', platform)
+
+    # When built against an older macOS SDK, Python will report macOS
+    # 10.16 instead of the real version.  Correct the tag reported by
+    # old packaging modules that do not contain yet a workaround.
+    # https://github.com/pypa/packaging/commit/67c4a2820c549070bbfc4bfbf5e2a250075048da
+    platform = re.sub(r'^macosx_10_16_(.*)$', r'macosx_11_0_\1', platform)
+
+    return platform
+
+
 package_dir = pathlib.Path(__file__).parent / 'packages'
 
 

tests/test_tags.py

@@ -12,16 +12,36 @@
 import pytest
 
 import mesonpy
+import mesonpy._tags
 
+from .conftest import adjust_packaging_platform_tag
 
+
+# Test against the wheel tag generated by packaging module.
 tag = next(packaging.tags.sys_tags())
 ABI = tag.abi
 INTERPRETER = tag.interpreter
-PLATFORM = mesonpy._adjust_manylinux_tag(tag.platform)
+PLATFORM = adjust_packaging_platform_tag(tag.platform)
+
 SUFFIX = sysconfig.get_config_var('EXT_SUFFIX')
 ABI3SUFFIX = next((x for x in mesonpy._EXTENSION_SUFFIXES if '.abi3.' in x), None)
 
 
+def test_wheel_tag():
+    str(mesonpy._tags.Tag()) == f'{INTERPRETER}-{ABI}-{PLATFORM}'
+    str(mesonpy._tags.Tag(abi='abi3')) == f'{INTERPRETER}-abi3-{PLATFORM}'
+
+
+@pytest.mark.skipif(platform.system() != 'Darwin', reason='macOS specific test')
+def test_macos_platform_tag(monkeypatch):
+    for minor in range(9, 16):
+        monkeypatch.setenv('MACOS_DEPLOYMENT_TARGET', f'10.{minor}')
+        assert next(packaging.tags.mac_platforms((10, minor))) == mesonpy._tags.get_platform_tag()
+    for major in range(11, 20):
+        monkeypatch.setenv('MACOS_DEPLOYMENT_TARGET', f'{major}.0')
+        assert next(packaging.tags.mac_platforms((major, 0))) == mesonpy._tags.get_platform_tag()
+
+
 def wheel_builder_test_factory(monkeypatch, content):
     files = defaultdict(list)
     files.update({key: [(pathlib.Path(x), os.path.join('build', x)) for x in value] for key, value in content.items()})

tests/test_wheel.py

@@ -14,14 +14,17 @@
 
 import mesonpy
 
+from .conftest import adjust_packaging_platform_tag
+
 
 EXT_SUFFIX = sysconfig.get_config_var('EXT_SUFFIX')
 INTERPRETER_VERSION = f'{sys.version_info[0]}{sys.version_info[1]}'
 
-_tag = next(packaging.tags.sys_tags())
-ABI = _tag.abi
-INTERPRETER = _tag.interpreter
-PLATFORM = mesonpy._adjust_manylinux_tag(_tag.platform)
+# Test against the wheel tag generated by packaging module.
+tag = next(packaging.tags.sys_tags())
+ABI = tag.abi
+INTERPRETER = tag.interpreter
+PLATFORM = adjust_packaging_platform_tag(tag.platform)
 
 if platform.system() == 'Linux':
     SHARED_LIB_EXT = 'so'