gh-82113: Fix ConfigParser.items() returning '' for value-less options

ConfigParser.items() always ran the option value through interpolation,
which turned a None value (a value-less option under allow_no_value=True)
into an empty string. get(), mapping access and dict(section) all return
None in that case. Skip interpolation when the stored value is None so
items() is consistent with the other accessors.

Author: iamsharduld

Lib/configparser.py

@@ -908,8 +908,10 @@ def items(self, section=_UNSET, raw=False, vars=None):
         if vars:
             for key, value in vars.items():
                 d[self.optionxform(key)] = value
-        value_getter = lambda option: self._interpolation.before_get(self,
-            section, option, d[option], d)
+        value_getter = lambda option: (
+            d[option] if d[option] is None
+            else self._interpolation.before_get(self, section, option,
+                                                 d[option], d))
         if raw:
             value_getter = lambda option: d[option]
         return [(option, value_getter(option)) for option in orig_keys]

Lib/test/test_configparser.py

@@ -1327,6 +1327,17 @@ def test_other_errors(self):
 class ConfigParserTestCaseNoValue(ConfigParserTestCase):
     allow_no_value = True
 
+    def test_items_reports_none_for_no_value(self):
+        # gh-82113: items() must report None (not '') for value-less options,
+        # consistent with get(), mapping access and dict(section).
+        cf = self.fromstring("[s]\nno_value\nspam = ham\n")
+        self.assertIsNone(cf.get("s", "no_value"))
+        self.assertIsNone(cf["s"]["no_value"])
+        self.assertEqual(sorted(cf.items("s")),
+                         [("no_value", None), ("spam", "ham")])
+        self.assertEqual(sorted(cf.items("s", raw=True)),
+                         [("no_value", None), ("spam", "ham")])
+
 
 class NoValueAndExtendedInterpolation(CfgParserTestCaseClass):
     interpolation = configparser.ExtendedInterpolation()

Misc/NEWS.d/next/Library/2026-06-22-13-30-00.gh-issue-82113.Rb8xKt.rst

@@ -0,0 +1,4 @@
+:meth:`configparser.ConfigParser.items` now reports ``None`` rather than an
+empty string for value-less options when ``allow_no_value`` is enabled, making
+it consistent with :meth:`~configparser.ConfigParser.get`, mapping access and
+``dict()`` conversion of a section.