fixup! Remove caching

Change-Id: Ieb6a6beccebcd39f8ff9027013fa9c592dc912c6

stevedore/extension.py

@@ -63,6 +63,29 @@ class Extension(object):
         match = self.entry_point.pattern.match(self.entry_point.value)
         return match.group('module')
 
+    @property
+    def extras(self):
+        """The 'extras' settings for the plugin."""
+        # NOTE: The underlying package returned re.Match objects until this was
+        # fixed in importlib-metadata 4.11.3. This was fixed in Python 3.10 and
+        # backported to Python 3.9.11. For older versions without this fix,
+        # translate the re.Match objects to the matched strings, which seem
+        # more useful.
+        extras = []
+        for extra in self.entry_point.extras:
+            if isinstance(extra, str):
+                # We were previously returning the whole string including
+                # backets. We need to continue doing so to preserve API
+                # compatibility.
+                extras.append(f'[{extra}]')
+            else:
+                # Python 3.6 returns _sre.SRE_Match objects. Later
+                # versions of python return re.Match objects. Both types
+                # have a 'string' attribute containing the text that
+                # matched the pattern.
+                extras.append(getattr(extra, 'string', extra))
+        return extras
+
     @property
     def attr(self):
         """The attribute of the module to be loaded."""

stevedore/tests/test_extension.py

@@ -251,6 +251,10 @@ class TestExtensionProperties(utils.TestCase):
         self.assertEqual('module.name', self.ext1.module_name)
         self.assertEqual('module', self.ext2.module_name)
 
+    def test_extras(self):
+        self.assertEqual(['[extra]'], self.ext1.extras)
+        self.assertEqual([], self.ext2.extras)
+
     def test_attr(self):
         self.assertEqual('attribute.name', self.ext1.attr)
         self.assertEqual('attribute', self.ext2.attr)