merge the python dependency from the python module into dependencies

We have two copies of this code, and the python module one is vastly
superior, not just because it allows choosing which python executable to
base itself on. Unify this. Fixes various issues including non-Windows
support for sysconfig, and pypy edge cases.

1 files changed, 144 insertions, 50 deletions

diff --git a/mesonbuild/dependencies/python.py b/mesonbuild/dependencies/python.py
index 2fc34c1..11691e5 100644
--- a/mesonbuild/dependencies/python.py
+++ b/mesonbuild/dependencies/python.py
@@ -13,13 +13,12 @@
 # limitations under the License.
 from __future__ import annotations
 
-import json, sysconfig
+import functools, json, os
 from pathlib import Path
 import typing as T
 
 from .. import mesonlib, mlog
-from .base import DependencyMethods, ExternalDependency, SystemDependency
-from .factory import DependencyFactory
+from .base import process_method_kw, DependencyMethods, DependencyTypeName, ExternalDependency, SystemDependency
 from .framework import ExtraFrameworkDependency
 from .pkgconfig import PkgConfigDependency
 from ..environment import detect_cpu_family
@@ -28,7 +27,9 @@ from ..programs import ExternalProgram
 if T.TYPE_CHECKING:
     from typing_extensions import TypedDict
 
+    from .factory import DependencyGenerator
     from ..environment import Environment
+    from ..mesonlib import MachineChoice
 
     class PythonIntrospectionDict(TypedDict):
 
@@ -162,25 +163,50 @@ class PythonFrameworkDependency(ExtraFrameworkDependency, _PythonDependencyBase)
         _PythonDependencyBase.__init__(self, installation, kwargs.get('embed', False))
 
 
-class Python3DependencySystem(SystemDependency):
-    def __init__(self, name: str, environment: 'Environment', kwargs: T.Dict[str, T.Any]) -> None:
-        super().__init__(name, environment, kwargs)
+class PythonSystemDependency(SystemDependency, _PythonDependencyBase):
 
-        if not environment.machines.matches_build_machine(self.for_machine):
-            return
-        if not environment.machines[self.for_machine].is_windows():
-            return
+    def __init__(self, name: str, environment: 'Environment',
+                 kwargs: T.Dict[str, T.Any], installation: 'BasicPythonExternalProgram'):
+        SystemDependency.__init__(self, name, environment, kwargs)
+        _PythonDependencyBase.__init__(self, installation, kwargs.get('embed', False))
 
-        self.name = 'python3'
-        # We can only be sure that it is Python 3 at this point
-        self.version = '3'
-        self._find_libpy3_windows(environment)
+        if mesonlib.is_windows():
+            self.find_libpy_windows(environment)
+        else:
+            self.find_libpy(environment)
 
-    @staticmethod
-    def get_windows_python_arch() -> T.Optional[str]:
-        pyplat = sysconfig.get_platform()
-        if pyplat == 'mingw':
-            pycc = sysconfig.get_config_var('CC')
+    def find_libpy(self, environment: 'Environment') -> None:
+        if self.is_pypy:
+            if self.major_version == 3:
+                libname = 'pypy3-c'
+            else:
+                libname = 'pypy-c'
+            libdir = os.path.join(self.variables.get('base'), 'bin')
+            libdirs = [libdir]
+        else:
+            libname = f'python{self.version}'
+            if 'DEBUG_EXT' in self.variables:
+                libname += self.variables['DEBUG_EXT']
+            if 'ABIFLAGS' in self.variables:
+                libname += self.variables['ABIFLAGS']
+            libdirs = []
+
+        largs = self.clib_compiler.find_library(libname, environment, libdirs)
+        if largs is not None:
+            self.link_args = largs
+
+        self.is_found = largs is not None or not self.link_libpython
+
+        inc_paths = mesonlib.OrderedSet([
+            self.variables.get('INCLUDEPY'),
+            self.paths.get('include'),
+            self.paths.get('platinclude')])
+
+        self.compile_args += ['-I' + path for path in inc_paths if path]
+
+    def get_windows_python_arch(self) -> T.Optional[str]:
+        if self.platform == 'mingw':
+            pycc = self.variables.get('CC')
             if pycc.startswith('x86_64'):
                 return '64'
             elif pycc.startswith(('i686', 'i386')):
@@ -188,38 +214,49 @@ class Python3DependencySystem(SystemDependency):
             else:
                 mlog.log(f'MinGW Python built with unknown CC {pycc!r}, please file a bug')
                 return None
-        elif pyplat == 'win32':
+        elif self.platform == 'win32':
             return '32'
-        elif pyplat in {'win64', 'win-amd64'}:
+        elif self.platform in {'win64', 'win-amd64'}:
             return '64'
-        mlog.log(f'Unknown Windows Python platform {pyplat!r}')
+        mlog.log(f'Unknown Windows Python platform {self.platform!r}')
         return None
 
     def get_windows_link_args(self) -> T.Optional[T.List[str]]:
-        pyplat = sysconfig.get_platform()
-        if pyplat.startswith('win'):
-            vernum = sysconfig.get_config_var('py_version_nodot')
+        if self.platform.startswith('win'):
+            vernum = self.variables.get('py_version_nodot')
+            verdot = self.variables.get('py_version_short')
+            imp_lower = self.variables.get('implementation_lower', 'python')
             if self.static:
                 libpath = Path('libs') / f'libpython{vernum}.a'
             else:
                 comp = self.get_compiler()
                 if comp.id == "gcc":
-                    libpath = Path(f'python{vernum}.dll')
+                    if imp_lower == 'pypy' and verdot == '3.8':
+                        # The naming changed between 3.8 and 3.9
+                        libpath = Path('libpypy3-c.dll')
+                    elif imp_lower == 'pypy':
+                        libpath = Path(f'libpypy{verdot}-c.dll')
+                    else:
+                        libpath = Path(f'python{vernum}.dll')
                 else:
                     libpath = Path('libs') / f'python{vernum}.lib'
-            lib = Path(sysconfig.get_config_var('base')) / libpath
-        elif pyplat == 'mingw':
+            # base_prefix to allow for virtualenvs.
+            lib = Path(self.variables.get('base_prefix')) / libpath
+        elif self.platform == 'mingw':
             if self.static:
-                libname = sysconfig.get_config_var('LIBRARY')
+                libname = self.variables.get('LIBRARY')
             else:
-                libname = sysconfig.get_config_var('LDLIBRARY')
-            lib = Path(sysconfig.get_config_var('LIBDIR')) / libname
+                libname = self.variables.get('LDLIBRARY')
+            lib = Path(self.variables.get('LIBDIR')) / libname
+        else:
+            raise mesonlib.MesonBugException(
+                'On a Windows path, but the OS doesn\'t appear to be Windows or MinGW.')
         if not lib.exists():
             mlog.log('Could not find Python3 library {!r}'.format(str(lib)))
             return None
         return [str(lib)]
 
-    def _find_libpy3_windows(self, env: 'Environment') -> None:
+    def find_libpy_windows(self, env: 'Environment') -> None:
         '''
         Find python3 libraries on Windows and also verify that the arch matches
         what we are building for.
@@ -241,8 +278,7 @@ class Python3DependencySystem(SystemDependency):
             return
         # Pyarch ends in '32' or '64'
         if arch != pyarch:
-            mlog.log('Need', mlog.bold(self.name), 'for {}-bit, but '
-                     'found {}-bit'.format(arch, pyarch))
+            mlog.log('Need', mlog.bold(self.name), f'for {arch}-bit, but found {pyarch}-bit')
             self.is_found = False
             return
         # This can fail if the library is not found
@@ -252,26 +288,84 @@ class Python3DependencySystem(SystemDependency):
             return
         self.link_args = largs
         # Compile args
-        inc = sysconfig.get_path('include')
-        platinc = sysconfig.get_path('platinclude')
-        self.compile_args = ['-I' + inc]
-        if inc != platinc:
-            self.compile_args.append('-I' + platinc)
-        self.version = sysconfig.get_config_var('py_version')
+        inc_paths = mesonlib.OrderedSet([
+            self.variables.get('INCLUDEPY'),
+            self.paths.get('include'),
+            self.paths.get('platinclude')])
+
+        self.compile_args += ['-I' + path for path in inc_paths if path]
+
+        # https://sourceforge.net/p/mingw-w64/mailman/message/30504611/
+        if pyarch == '64' and self.major_version == 2:
+            self.compile_args += ['-DMS_WIN64']
+
         self.is_found = True
 
     @staticmethod
     def log_tried() -> str:
         return 'sysconfig'
 
+def python_factory(env: 'Environment', for_machine: 'MachineChoice',
+                   kwargs: T.Dict[str, T.Any],
+                   installation: T.Optional['BasicPythonExternalProgram'] = None) -> T.List['DependencyGenerator']:
+    # We can't use the factory_methods decorator here, as we need to pass the
+    # extra installation argument
+    methods = process_method_kw({DependencyMethods.PKGCONFIG, DependencyMethods.SYSTEM}, kwargs)
+    embed = kwargs.get('embed', False)
+    candidates: T.List['DependencyGenerator'] = []
+    from_installation = installation is not None
+    # When not invoked through the python module, default installation.
+    if installation is None:
+        installation = BasicPythonExternalProgram('python3', mesonlib.python_command)
+        installation.sanity()
+    pkg_version = installation.info['variables'].get('LDVERSION') or installation.info['version']
+
+    if DependencyMethods.PKGCONFIG in methods:
+        if from_installation:
+            pkg_libdir = installation.info['variables'].get('LIBPC')
+            pkg_embed = '-embed' if embed and mesonlib.version_compare(installation.info['version'], '>=3.8') else ''
+            pkg_name = f'python-{pkg_version}{pkg_embed}'
+
+            # If python-X.Y.pc exists in LIBPC, we will try to use it
+            def wrap_in_pythons_pc_dir(name: str, env: 'Environment', kwargs: T.Dict[str, T.Any],
+                                       installation: 'BasicPythonExternalProgram') -> 'ExternalDependency':
+                if not pkg_libdir:
+                    # there is no LIBPC, so we can't search in it
+                    empty = ExternalDependency(DependencyTypeName('pkgconfig'), env, {})
+                    empty.name = 'python'
+                    return empty
+
+                old_pkg_libdir = os.environ.pop('PKG_CONFIG_LIBDIR', None)
+                old_pkg_path = os.environ.pop('PKG_CONFIG_PATH', None)
+                os.environ['PKG_CONFIG_LIBDIR'] = pkg_libdir
+                try:
+                    return PythonPkgConfigDependency(name, env, kwargs, installation, True)
+                finally:
+                    def set_env(name: str, value: str) -> None:
+                        if value is not None:
+                            os.environ[name] = value
+                        elif name in os.environ:
+                            del os.environ[name]
+                    set_env('PKG_CONFIG_LIBDIR', old_pkg_libdir)
+                    set_env('PKG_CONFIG_PATH', old_pkg_path)
+
+            candidates.append(functools.partial(wrap_in_pythons_pc_dir, pkg_name, env, kwargs, installation))
+            # We only need to check both, if a python install has a LIBPC. It might point to the wrong location,
+            # e.g. relocated / cross compilation, but the presence of LIBPC indicates we should definitely look for something.
+            if pkg_libdir is not None:
+                candidates.append(functools.partial(PythonPkgConfigDependency, pkg_name, env, kwargs, installation))
+        else:
+            candidates.append(functools.partial(PkgConfigDependency, 'python3', env, kwargs))
+
+    if DependencyMethods.SYSTEM in methods:
+        candidates.append(functools.partial(PythonSystemDependency, 'python', env, kwargs, installation))
+
+    if DependencyMethods.EXTRAFRAMEWORK in methods:
+        nkwargs = kwargs.copy()
+        if mesonlib.version_compare(pkg_version, '>= 3'):
+            # There is a python in /System/Library/Frameworks, but that's python 2.x,
+            # Python 3 will always be in /Library
+            nkwargs['paths'] = ['/Library/Frameworks']
+        candidates.append(functools.partial(PythonFrameworkDependency, 'Python', env, nkwargs, installation))
 
-python3_factory = DependencyFactory(
-    'python3',
-    [DependencyMethods.PKGCONFIG, DependencyMethods.SYSTEM, DependencyMethods.EXTRAFRAMEWORK],
-    system_class=Python3DependencySystem,
-    # There is no version number in the macOS version number
-    framework_name='Python',
-    # There is a python in /System/Library/Frameworks, but that's python 2.x,
-    # Python 3 will always be in /Library
-    extra_kwargs={'paths': ['/Library/Frameworks']},
-)
+    return candidates