python module: allow specifying the pure kwarg in the installation object

Fixes #10523

docs/markdown/snippets/python-installation-pure.md

@@ -0,0 +1,8 @@
+## python.find_installation() now accepts pure argument
+
+The default value of `pure:` for `py.install_sources()` and
+`py.get_install_dir()` can now be changed by explicitly passing a `pure:` kwarg
+to `find_installation()`.
+
+This can be used to ensure that multiple `install_sources()` invocations do not
+forget to specify the kwarg each time.

mesonbuild/modules/python.py

@@ -14,6 +14,7 @@
 from __future__ import annotations
 
 from pathlib import Path
+import copy
 import functools
 import json
 import os
@@ -67,7 +68,7 @@ if T.TYPE_CHECKING:
 
     class PyInstallKw(TypedDict):
 
-        pure: bool
+        pure: T.Optional[bool]
         subdir: str
         install_tag: T.Optional[str]
 
@@ -75,6 +76,7 @@ if T.TYPE_CHECKING:
 
         disabler: bool
         modules: T.List[str]
+        pure: T.Optional[bool]
 
     _Base = ExternalDependency
 else:
@@ -409,6 +411,7 @@ class PythonExternalProgram(ExternalProgram):
             'variables': {},
             'version': '0.0',
         }
+        self.pure: bool = True
 
     def _check_version(self, version: str) -> bool:
         if self.name == 'python2':
@@ -472,7 +475,7 @@ class PythonExternalProgram(ExternalProgram):
         return rel_path
 
 
-_PURE_KW = KwargInfo('pure', bool, default=True)
+_PURE_KW = KwargInfo('pure', (bool, NoneType))
 _SUBDIR_KW = KwargInfo('subdir', str, default='')
 
 
@@ -485,6 +488,7 @@ class PythonInstallation(ExternalProgramHolder):
         self.variables = info['variables']
         self.suffix = info['suffix']
         self.paths = info['paths']
+        self.pure = python.pure
         self.platlib_install_path = os.path.join(prefix, python.platlib)
         self.purelib_install_path = os.path.join(prefix, python.purelib)
         self.version = info['version']
@@ -599,7 +603,8 @@ class PythonInstallation(ExternalProgramHolder):
     def install_sources_method(self, args: T.Tuple[T.List[T.Union[str, mesonlib.File]]],
                                kwargs: 'PyInstallKw') -> 'Data':
         tag = kwargs['install_tag'] or 'runtime'
-        install_dir = self._get_install_dir_impl(kwargs['pure'], kwargs['subdir'])
+        pure = kwargs['pure'] if kwargs['pure'] is not None else self.pure
+        install_dir = self._get_install_dir_impl(pure, kwargs['subdir'])
         return self.interpreter.install_data_impl(
             self.interpreter.source_strings_to_files(args[0]),
             install_dir,
@@ -610,7 +615,8 @@ class PythonInstallation(ExternalProgramHolder):
     @noPosargs
     @typed_kwargs('python_installation.install_dir', _PURE_KW, _SUBDIR_KW)
     def get_install_dir_method(self, args: T.List['TYPE_var'], kwargs: 'PyInstallKw') -> str:
-        return self._get_install_dir_impl(kwargs['pure'], kwargs['subdir'])
+        pure = kwargs['pure'] if kwargs['pure'] is not None else self.pure
+        return self._get_install_dir_impl(pure, kwargs['subdir'])
 
     def _get_install_dir_impl(self, pure: bool, subdir: str) -> P_OBJ.OptionString:
         if pure:
@@ -733,6 +739,7 @@ class PythonModule(ExtensionModule):
         KwargInfo('required', (bool, UserFeatureOption), default=True),
         KwargInfo('disabler', bool, default=False, since='0.49.0'),
         KwargInfo('modules', ContainerTypeInfo(list, str), listify=True, default=[], since='0.51.0'),
+        _PURE_KW.evolve(default=True, since='0.64.0'),
     )
     def find_installation(self, state: 'ModuleState', args: T.Tuple[T.Optional[str]],
                           kwargs: 'FindInstallationKw') -> ExternalProgram:
@@ -797,6 +804,8 @@ class PythonModule(ExtensionModule):
                 raise mesonlib.MesonException('{} is missing modules: {}'.format(name_or_path or 'python', ', '.join(missing_modules)))
             return NonExistingExternalProgram()
         else:
+            python = copy.copy(python)
+            python.pure = kwargs['pure']
             return python
 
         raise mesonlib.MesonBugException('Unreachable code was reached (PythonModule.find_installation).')

test cases/python/7 install path/meson.build

@@ -8,5 +8,13 @@ project('install path',
 py = import('python').find_installation()
 py.install_sources('test.py')
 py.install_sources('test.py', pure: false)
+install_data('test.py', install_dir: py.get_install_dir() / 'data')
+install_data('test.py', install_dir: py.get_install_dir(pure: false) / 'data')
+
+py_plat = import('python').find_installation(pure: false)
+py_plat.install_sources('test.py', subdir: 'kw')
+py_plat.install_sources('test.py', pure: true, subdir: 'kwrevert')
+install_data('test.py', install_dir: py_plat.get_install_dir() / 'kw/data')
+install_data('test.py', install_dir: py_plat.get_install_dir(pure: true) / 'kwrevert/data')
 
 subdir('structured')

test cases/python/7 install path/test.json

@@ -6,7 +6,13 @@
     {"type": "file", "file": "pure/alpha/two.py"},
     {"type": "file", "file": "pure/alpha/three.py"},
     {"type": "file", "file": "pure/beta/one.py"},
+    {"type": "file", "file": "plat/kw/test.py"},
+    {"type": "file", "file": "pure/kwrevert/test.py"},
     {"type": "file", "file": "plat/test.py"},
-    {"type": "file", "file": "pure/test.py"}
+    {"type": "file", "file": "pure/test.py"},
+    {"type": "file", "file": "plat/data/test.py"},
+    {"type": "file", "file": "pure/data/test.py"},
+    {"type": "file", "file": "plat/kw/data/test.py"},
+    {"type": "file", "file": "pure/kwrevert/data/test.py"}
   ]
 }