bpo-44631: Make the repr() of the _Environ class more readable. (#27128)

Co-authored-by: Łukasz Langa <lukasz@langa.pl>

Lib/os.py

@@ -704,9 +704,11 @@ class _Environ(MutableMapping):
         return len(self._data)
 
     def __repr__(self):
-        return 'environ({{{}}})'.format(', '.join(
-            ('{!r}: {!r}'.format(self.decodekey(key), self.decodevalue(value))
-            for key, value in self._data.items())))
+        formatted_items = ", ".join(
+            f"{self.decodekey(key)!r}: {self.decodevalue(value)!r}"
+            for key, value in self._data.items()
+        )
+        return f"environ({{{formatted_items}}})"
 
     def copy(self):
         return dict(self)

Lib/test/test_os.py

@@ -1029,9 +1029,11 @@ class EnvironTests(mapping_tests.BasicTestMappingProtocol):
     def test___repr__(self):
         """Check that the repr() of os.environ looks like environ({...})."""
         env = os.environ
-        self.assertEqual(repr(env), 'environ({{{}}})'.format(', '.join(
-            '{!r}: {!r}'.format(key, value)
-            for key, value in env.items())))
+        formatted_items = ", ".join(
+            f"{key!r}: {value!r}"
+            for key, value in env.items()
+        )
+        self.assertEqual(repr(env), f"environ({{{formatted_items}}})")
 
     def test_get_exec_path(self):
         defpath_list = os.defpath.split(os.pathsep)

Misc/NEWS.d/next/Documentation/2021-07-13-22-25-13.bpo-44631.qkGwe4.rst

@@ -0,0 +1 @@
+Refactored the ``repr()`` code of the ``_Environ`` (os module).