Make isolated source changes @ PEP 517 backend (#80253)

packaging/pep517_backend/_backend.py

@@ -7,10 +7,24 @@ import subprocess
 import sys
 import typing as t
 from configparser import ConfigParser
-from contextlib import suppress
+from contextlib import contextmanager, suppress
 from importlib.metadata import import_module
 from io import StringIO
 from pathlib import Path
+from shutil import copytree
+from tempfile import TemporaryDirectory
+
+try:
+    from contextlib import chdir as _chdir_cm
+except ImportError:
+    @contextmanager
+    def _chdir_cm(path: os.PathLike) -> t.Iterator[None]:
+        original_wd = Path.cwd()
+        os.chdir(path)
+        try:
+            yield
+        finally:
+            os.chdir(original_wd)
 
 from setuptools.build_meta import (
     build_sdist as _setuptools_build_sdist,
@@ -33,6 +47,13 @@ BUILD_MANPAGES_CONFIG_SETTING = '--build-manpages'
 """Config setting name toggle that is used to request manpage in sdists."""
 
 
+@contextmanager
+def _run_in_temporary_directory() -> t.Iterator[Path]:
+    with TemporaryDirectory(prefix='.tmp-ansible-pep517-') as tmp_dir:
+        with _chdir_cm(tmp_dir):
+            yield Path(tmp_dir)
+
+
 def _make_in_tree_ansible_importable() -> None:
     """Add the library directory to module lookup paths."""
     lib_path = str(Path.cwd() / 'lib/')
@@ -93,6 +114,12 @@ def build_sdist(  # noqa: WPS210, WPS430
     build_manpages_requested = BUILD_MANPAGES_CONFIG_SETTING in (
         config_settings or {}
     )
+    original_src_dir = Path.cwd().resolve()
+    with _run_in_temporary_directory() as tmp_dir:
+        tmp_src_dir = Path(tmp_dir) / 'src'
+        copytree(original_src_dir, tmp_src_dir)
+        os.chdir(tmp_src_dir)
+
         if build_manpages_requested:
             Path('docs/man/man1/').mkdir(exist_ok=True, parents=True)
             version_number = _get_package_distribution_version()
@@ -104,11 +131,13 @@ def build_sdist(  # noqa: WPS210, WPS430
                 )
                 rst_in.unlink()
 
-    return _setuptools_build_sdist(
+        built_sdist_basename = _setuptools_build_sdist(
             sdist_directory=sdist_directory,
             config_settings=config_settings,
         )
 
+    return built_sdist_basename
+
 
 def get_requires_for_build_sdist(
         config_settings: dict[str, str] | None = None,