Add '_compat.repair_extras' to repair extras from older, broken impor…

…tlib metadata implementations.

nspektr/__init__.py

@@ -8,20 +8,20 @@
 from jaraco.context import suppress
 from jaraco.functools import apply
 
-from ._compat import metadata
+from ._compat import metadata, repair_extras
 
 
 def resolve(req: Requirement):
     """
     >>> resolve(Requirement('pytest<3'))
     Traceback (most recent call last):
     ...
-    importlib_metadata.PackageNotFoundError: No package metadata was found for pytest<3
+    importlib.metadata.PackageNotFoundError: No package metadata was found for pytest<3
     """
     dist = metadata.distribution(req.name)
     if not req.specifier.contains(Version(dist.version), prereleases=True):
         raise metadata.PackageNotFoundError(str(req))
-    dist.extras = req.extras  # type: ignore
+    dist.extras = repair_extras(req.extras)  # type: ignore
     return dist
 
 
@@ -124,6 +124,6 @@ def check(ep):
     ...
     ValueError: ('Unable to resolve all dependencies',...
     """
-    missing = list(unsatisfied(find_dependencies(ep.dist, ep.extras)))
+    missing = list(unsatisfied(find_dependencies(ep.dist, repair_extras(ep.extras))))
     if missing:
         raise ValueError("Unable to resolve all dependencies", missing)

nspektr/_compat.py

@@ -1,5 +1,20 @@
-if False:
-    # bugfix from 4.11.2 is required
+import contextlib
+
+
+try:
     import importlib.metadata as metadata
-else:
+except ImportError:
     import importlib_metadata as metadata  # type: ignore # noqa: F401
+
+
+def repair_extras(extras):
+    """
+    Repair extras that appear as match objects.
+
+    python/importlib_metadata#369 revealed a flaw in the EntryPoint
+    implementation. This function wraps the extras to ensure
+    they are proper strings even on older implementations.
+    """
+    with contextlib.suppress(AttributeError):
+        return list(item.group(0) for item in extras)
+    return extras

setup.cfg

@@ -21,7 +21,7 @@ install_requires =
 	jaraco.functools
 	more_itertools
 	packaging
-	importlib_metadata >= 4.11.2
+	importlib_metadata; python_version < "3.8"
 
 [options.packages.find]
 exclude =