Fix importlib(_|.)metadata handling for various python versions

src/typeguard/_checkers.py

@@ -67,11 +67,14 @@
     )
     from typing_extensions import Any as SubclassableAny
 
-if sys.version_info >= (3, 10):
+if sys.version_info < (3,8):
+    from importlib_metadata import entry_points
+else:
     from importlib.metadata import entry_points
+
+if sys.version_info >= (3, 10):
     from typing import ParamSpec
 else:
-    from importlib_metadata import entry_points
     from typing_extensions import ParamSpec
 
 TypeCheckerCallable: TypeAlias = Callable[
@@ -847,7 +850,12 @@ def load_plugins() -> None:
         ``TYPEGUARD_DISABLE_PLUGIN_AUTOLOAD`` environment variable is present.
     """
 
-    for ep in entry_points(group="typeguard.checker_lookup"):
+    group = "typeguard.checker_lookup"
+    if sys.version_info >= (3, 10):
+        eps = entry_points(group=group)
+    else:
+        eps = entry_points().get(group, ())
+    for ep in eps:
         try:
             plugin = ep.load()
         except Exception as exc:

tests/test_plugins.py

@@ -1,3 +1,5 @@
+import sys
+
 from pytest import MonkeyPatch
 
 from typeguard import load_plugins
@@ -12,10 +14,13 @@ class FakeEntryPoint:
 
         def load(self):
             return lookup_func
-
-    def fake_entry_points(group):
-        assert group == "typeguard.checker_lookup"
-        return [FakeEntryPoint()]
+    if sys.version_info >= (3, 10):
+        def fake_entry_points(group):
+            assert group == "typeguard.checker_lookup"
+            return [FakeEntryPoint()]
+    else:
+        def fake_entry_points():
+            return {"typeguard.checker_lookup":[FakeEntryPoint()]}
 
     checker_lookup_functions = []
     monkeypatch.setattr("typeguard._checkers.entry_points", fake_entry_points)