🐛 fix(backend): make wildcard imports work

docs/changelog.d/+backend-config-settings.bugfix.rst

@@ -0,0 +1 @@
+Expose ``ConfigSettings`` at runtime so wildcard imports from ``python_sbom.backend`` no longer fail.

src/python_sbom/backend.py

@@ -3,19 +3,18 @@
 from __future__ import annotations
 
 import importlib
+from collections.abc import Mapping as _Mapping
 from functools import cache, reduce
 from pathlib import Path
-from typing import TYPE_CHECKING, Final, Protocol, cast
+from typing import Final, Protocol, cast
+from typing import TypeAlias as _TypeAlias
 
 from ._collect._revision import REVISION_FILE, default_revision, revision_record
 from ._collect._settings import settings_from_pyproject
 from ._errors import SbomError
 
-if TYPE_CHECKING:
-    from collections.abc import Mapping
-
-    #: the settings a frontend passes each hook, such as ``--config-settings`` of pip and build
-    ConfigSettings = Mapping[str, str | list[str]] | None
+#: the settings a frontend passes each hook, such as ``--config-settings`` of pip and build
+ConfigSettings: _TypeAlias = _Mapping[str, str | list[str]] | None
 
 # the hooks PEP 517 and PEP 660 let a backend leave out, which a frontend then replaces with its own default
 _OPTIONAL_HOOKS: Final[frozenset[str]] = frozenset({

tests/test_backend_star.py

@@ -0,0 +1,15 @@
+from __future__ import annotations
+
+import subprocess
+import sys
+
+
+def test_backend_wildcard_import() -> None:
+    code = (
+        "from collections.abc import Mapping\n"
+        "from python_sbom.backend import *\n"
+        "assert ConfigSettings == Mapping[str, str | list[str]] | None\n"
+        "assert callable(build_sdist) and callable(build_wheel)\n"
+        "print('imported')\n"
+    )
+    assert subprocess.check_output([sys.executable, "-c", code], text=True) == "imported\n"