WIP: ENH: implement support for build-details.json (PEP 739)

Signed-off-by: Michał Górny <mgorny@quansight.com>

Author: rgommers

mesonpy/__init__.py

@@ -340,6 +340,8 @@ class _WheelBuilder():
     _manifest: Dict[str, List[_Entry]]
     _limited_api: bool
     _allow_windows_shared_libs: bool
+    _is_cross: bool
+    _build_details: mesonpy._tags.BuildDetailsDict
 
     @property
     def _has_internal_libs(self) -> bool:
@@ -370,8 +372,8 @@ def tag(self) -> mesonpy._tags.Tag:
             # does not contain any extension module (does not
             # distribute any file in {platlib}) thus use generic
             # implementation and ABI tags.
-            return mesonpy._tags.Tag('py3', 'none', None)
-        return mesonpy._tags.Tag(None, self._stable_abi, None)
+            return mesonpy._tags.Tag('py3', 'none', None, self._build_details)
+        return mesonpy._tags.Tag(None, self._stable_abi, None, self._build_details)
 
     @property
     def name(self) -> str:
@@ -834,6 +836,21 @@ def __init__(
         ''')
         self._meson_native_file.write_text(native_file_data, encoding='utf-8')
 
+        # Handle cross compilation
+        self._is_cross = any(s.startswith('--cross-file') for s in self._meson_args['setup'])
+        self._build_details = None
+        # Use build-details.json (PEP 739) to determine
+        # platform/interpreter/abi tags, if given.
+        for setup_arg in reversed(self._meson_args['setup']):
+            if setup_arg.startswith('-Dpython.build_config='):
+                with open(setup_arg.split('=', 1)[1]) as f:
+                    self._build_details = json.load(f)
+                break
+        else:
+            if self._is_cross:
+                # TODO: warn that interpreter details may be wrong. Get platform from cross file.
+                pass
+
         # reconfigure if we have a valid Meson build directory. Meson
         # uses the presence of the 'meson-private/coredata.dat' file
         # in the build directory as indication that the build
@@ -1151,13 +1168,17 @@ def sdist(self, directory: Path) -> pathlib.Path:
     def wheel(self, directory: Path) -> pathlib.Path:
         """Generates a wheel in the specified directory."""
         self.build()
-        builder = _WheelBuilder(self._metadata, self._manifest, self._limited_api, self._allow_windows_shared_libs)
+        builder = _WheelBuilder(
+            self._metadata, self._manifest, self._limited_api, self._allow_windows_shared_libs,
+            self._is_cross, self._build_details)
         return builder.build(directory)
 
     def editable(self, directory: Path) -> pathlib.Path:
         """Generates an editable wheel in the specified directory."""
         self.build()
-        builder = _EditableWheelBuilder(self._metadata, self._manifest, self._limited_api, self._allow_windows_shared_libs)
+        builder = _EditableWheelBuilder(
+            self._metadata, self._manifest, self._limited_api, self._allow_windows_shared_libs,
+            self._is_cross, self._build_details)
         return builder.build(directory, self._source_dir, self._build_dir, self._build_command, self._editable_verbose)
 
 

mesonpy/_tags.py

@@ -15,6 +15,24 @@
 if typing.TYPE_CHECKING:  # pragma: no cover
     from typing import Optional, Union
 
+    from mesonpy._compat import TypedDict
+
+    class _AbiDict(TypedDict):
+        extension_suffix: str
+
+    class _ImplementationVersionDict(TypedDict):
+        major: int
+        minor: int
+
+    class _ImplementationDict(TypedDict):
+        name: str
+        version: _ImplementationVersionDict
+
+    class BuildDetailsDict(TypedDict):
+        abi: _AbiDict
+        implementation: _ImplementationDict
+        platform: str
+
 
 # https://peps.python.org/pep-0425/#python-tag
 INTERPRETERS = {
@@ -29,11 +47,17 @@
 _32_BIT_INTERPRETER = struct.calcsize('P') == 4
 
 
-def get_interpreter_tag() -> str:
-    name = sys.implementation.name
+def get_interpreter_tag(build_details: Optional[BuildDetailsDict] = None) -> str:
+    if build_details is None:
+        name = sys.implementation.name
+        major, minor = sys.version_info[:2]
+    else:
+        name = build_details['implementation']['name']
+        _v = build_details['implementation']['version']
+        major = _v['major']
+        minor = _v['minor']
     name = INTERPRETERS.get(name, name)
-    version = sys.version_info
-    return f'{name}{version[0]}{version[1]}'
+    return f'{name}{major}{minor}'
 
 
 def _get_config_var(name: str, default: Union[str, int, None] = None) -> Union[str, int, None]:
@@ -53,7 +77,12 @@ def _get_cpython_abi() -> str:
     return f'cp{version[0]}{version[1]}{debug}{pymalloc}'
 
 
-def get_abi_tag() -> str:
+def get_abi_tag(build_details: Optional[BuildDetailsDict] = None) -> str:
+    if build_details is not None:
+        ext_suffix = build_details['abi']['extension_suffix']
+    else:
+        ext_suffix = sysconfig.get_config_var('EXT_SUFFIX')
+
     # The best solution to obtain the Python ABI is to parse the
     # $SOABI or $EXT_SUFFIX sysconfig variables as defined in PEP-314.
 
@@ -62,7 +91,7 @@ def get_abi_tag() -> str:
     # See https://foss.heptapod.net/pypy/pypy/-/issues/3816 and
     # https://github.com/pypa/packaging/pull/607.
     try:
-        empty, abi, ext = str(sysconfig.get_config_var('EXT_SUFFIX')).split('.')
+        empty, abi, ext = str(ext_suffix).split('.')
     except ValueError as exc:
         # CPython <= 3.8.7 on Windows does not implement PEP3149 and
         # uses '.pyd' as $EXT_SUFFIX, which does not allow to extract
@@ -178,8 +207,8 @@ def _get_ios_platform_tag() -> str:
     return f'ios_{version[0]}_{version[1]}_{multiarch}'
 
 
-def get_platform_tag() -> str:
-    platform = sysconfig.get_platform()
+def get_platform_tag(build_details: Optional[BuildDetailsDict] = None) -> str:
+    platform = build_details['platform'] if build_details is not None else sysconfig.get_platform()
     if platform.startswith('macosx'):
         return _get_macosx_platform_tag()
     if platform.startswith('ios'):
@@ -194,10 +223,11 @@ def get_platform_tag() -> str:
 
 
 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 __init__(self, interpreter: Optional[str] = None, abi: Optional[str] = None, platform: Optional[str] = None,
+                 build_details: Optional[BuildDetailsDict] = None):
+        self.interpreter = interpreter or get_interpreter_tag(build_details)
+        self.abi = abi or get_abi_tag(build_details)
+        self.platform = platform or get_platform_tag(build_details)
 
     def __str__(self) -> str:
         return f'{self.interpreter}-{self.abi}-{self.platform}'

tests/test_tags.py

@@ -3,6 +3,7 @@
 # SPDX-License-Identifier: MIT
 
 import importlib.machinery
+import json
 import os
 import pathlib
 import platform
@@ -39,8 +40,18 @@ def get_abi3_suffix():
             return suffix
 
 
+def get_build_details_json():
+    # Technically, this is only applicable to 3.14+, but we account for FileNotFoundError anyway.
+    try:
+        with open(pathlib.Path(sysconfig.get_path('stdlib')) / 'build-details.json') as f:
+            return json.load(f)
+    except FileNotFoundError:
+        return None
+
+
 SUFFIX = sysconfig.get_config_var('EXT_SUFFIX')
 ABI3SUFFIX = get_abi3_suffix()
+BUILD_DETAILS_JSON = get_build_details_json()
 
 
 def test_wheel_tag():
@@ -106,7 +117,7 @@ def wheel_builder_test_factory(content, pure=True, limited_api=False):
     manifest = defaultdict(list)
     for key, value in content.items():
         manifest[key] = [mesonpy._Entry(pathlib.Path(x), os.path.join('build', x)) for x in value]
-    return mesonpy._WheelBuilder(None, manifest, limited_api, False)
+    return mesonpy._WheelBuilder(None, manifest, limited_api, False, False, None)
 
 
 def test_tag_empty_wheel():
@@ -149,3 +160,8 @@ def test_tag_mixed_abi():
     }, pure=False, limited_api=True)
     with pytest.raises(mesonpy.BuildError, match='The package declares compatibility with Python limited API but '):
         assert str(builder.tag) == f'{INTERPRETER}-abi3-{PLATFORM}'
+
+
+@pytest.mark.skipif(BUILD_DETAILS_JSON is None, reason='No build-details.json for this interpreter')
+def test_system_build_details():
+    assert str(mesonpy._tags.Tag()) == str(mesonpy._tags.Tag(build_details=BUILD_DETAILS_JSON))

tests/test_wheel.py

@@ -255,7 +255,7 @@ def test_entrypoints(wheel_full_metadata):
 def test_top_level_modules(package_module_types):
     with mesonpy._project() as project:
         builder = mesonpy._EditableWheelBuilder(
-            project._metadata, project._manifest, project._limited_api, project._allow_windows_shared_libs)
+            project._metadata, project._manifest, project._limited_api, project._allow_windows_shared_libs, False, None)
         assert set(builder._top_level_modules) == {
             'file',
             'package',