fix #1131: allow self-build without importlib_metadata

Author: RonnyPfannschmidt

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## v8.3.1
+
+### Fixed
+
+- fixed #1131: allow self-build without importlib_metadata avaliable on python3.9
+
 ## v8.3.0
 
 ### Fixed

pyproject.toml

@@ -5,7 +5,6 @@ build-backend = "_own_version_helper:build_meta"
 requires = [
   "setuptools>=61",
   'tomli<=2.0.2; python_version < "3.11"',
-  'importlib-metadata>=4.6; python_version < "3.10"',
 ]
 backend-path = [
   ".",

src/setuptools_scm/_entrypoints.py

@@ -12,22 +12,33 @@
 from . import _log
 from . import version
 
+__all__ = [
+    "entry_points",
+    "im",
+]
 if TYPE_CHECKING:
     from . import _types as _t
     from ._config import Configuration
     from ._config import ParseFunction
 
-if sys.version_info[:2] < (3, 10):
-    from importlib_metadata import EntryPoint as EntryPoint
-    from importlib_metadata import entry_points as entry_points
-else:
-    from importlib.metadata import EntryPoint as EntryPoint
-    from importlib.metadata import entry_points as entry_points
+    if sys.version_info[:2] < (3, 10):
+        import importlib_metadata as im
+    else:
+        from importlib import metadata as im
 
 
 log = _log.log.getChild("entrypoints")
 
 
+def entry_points(**kw: Any) -> im.EntryPoints:
+    if sys.version_info[:2] < (3, 10):
+        import importlib_metadata as im
+    else:
+        import importlib.metadata as im
+
+    return im.entry_points(**kw)
+
+
 def version_from_entrypoint(
     config: Configuration, *, entrypoint: str, root: _t.PathT
 ) -> version.ScmVersion | None:
@@ -52,6 +63,8 @@ def _get_ep(group: str, name: str) -> Any | None:
 
 def _get_from_object_reference_str(path: str, group: str) -> Any | None:
     # todo: remove for importlib native spelling
+    from importlib.metadata import EntryPoint  # hack
+
     ep = EntryPoint(path, path, group)
     try:
         return ep.load()

src/setuptools_scm/_file_finders/__init__.py

@@ -7,7 +7,6 @@
 
 from .. import _log
 from .. import _types as _t
-from .._entrypoints import EntryPoint
 from .._entrypoints import entry_points
 from .pathtools import norm_real
 
@@ -102,7 +101,7 @@ def is_toplevel_acceptable(toplevel: str | None) -> TypeGuard[str]:
 
 
 def find_files(path: _t.PathT = "") -> list[str]:
-    eps: list[EntryPoint] = [
+    eps = [
         *entry_points(group="setuptools_scm.files_command"),
         *entry_points(group="setuptools_scm.files_command_fallback"),
     ]

src/setuptools_scm/discover.py

@@ -3,6 +3,7 @@
 import os
 
 from pathlib import Path
+from typing import TYPE_CHECKING
 from typing import Iterable
 from typing import Iterator
 
@@ -11,6 +12,10 @@
 from . import _types as _t
 from ._config import Configuration
 
+if TYPE_CHECKING:
+    from ._entrypoints import im
+
+
 log = _log.log.getChild("discover")
 
 
@@ -48,7 +53,7 @@ def match_entrypoint(root: _t.PathT, name: str) -> bool:
 
 def iter_matching_entrypoints(
     root: _t.PathT, entrypoint: str, config: Configuration
-) -> Iterable[_entrypoints.EntryPoint]:
+) -> Iterable[im.EntryPoint]:
     """
     Consider different entry-points in ``root`` and optionally its parents.
     :param root: File path.