From b73f7ae4175b155f4251a9bd8069fabce33818cc Mon Sep 17 00:00:00 2001
From: sundeep8967 <sundeep8967@gmail.com>
Date: Wed, 26 Aug 2026 02:25:33 +0530
Subject: [PATCH 1/5] gh-156353: Fix configparser space delimiter parsing

This commit fixes a bug introduced in gh-146333 where using a space as a delimiter would cause the option name parsing to incorrectly absorb the space.

The regular expressions _OPT_TMPL and _OPT_NV_TMPL have been adjusted to ensure that whitespace matches do not consume valid delimiters.

Signed-off-by: sundeep8967 <sundeep8967@gmail.com>
---
 Lib/configparser.py           | 4 ++--
 Lib/test/test_configparser.py | 7 +++++++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/Lib/configparser.py b/Lib/configparser.py
index 3c452afe8ade485..26207fbbdaaf458 100644
--- a/Lib/configparser.py
+++ b/Lib/configparser.py
@@ -618,7 +618,7 @@ class RawConfigParser(MutableMapping):
     _OPT_TMPL = r"""
         (?P<option>                        # very permissive!
             (?:(?!{delim})\S)*             # non-delimiter non-whitespace
-            (?:\s+(?:(?!{delim})\S)+)*)    # optionally more words
+            (?:(?:(?!{delim})\s)+(?:(?!{delim})\S)+)*)    # optionally more words
         \s*(?P<vi>{delim})\s*              # any number of space/tab,
                                            # followed by any of the
                                            # allowed delimiters,
@@ -628,7 +628,7 @@ class RawConfigParser(MutableMapping):
     _OPT_NV_TMPL = r"""
         (?P<option>                        # very permissive!
             (?:(?!{delim})\S)*             # non-delimiter non-whitespace
-            (?:\s+(?:(?!{delim})\S)+)*)    # optionally more words
+            (?:(?:(?!{delim})\s)+(?:(?!{delim})\S)+)*)    # optionally more words
         \s*(?:                             # any number of space/tab,
         (?P<vi>{delim})\s*                 # optionally followed by
                                            # any of the allowed
diff --git a/Lib/test/test_configparser.py b/Lib/test/test_configparser.py
index 4783943f71a1092..7d395232fdc3782 100644
--- a/Lib/test/test_configparser.py
+++ b/Lib/test/test_configparser.py
@@ -358,6 +358,13 @@ def test_basic(self):
                 the larch {0[1]} 1
             """.format(self.delimiters)))
 
+    def test_space_delimiter(self):
+        # gh-156353: Space should be accepted as a delimiter
+        cf = self.newconfig(delimiters=(' ', '='))
+        cf.read_string("[all]\nfoo bar=baz")
+        self.assertEqual(cf.options('all'), ['foo'])
+        self.assertEqual(cf.get('all', 'foo'), 'bar=baz')
+
     def test_basic_from_dict(self):
         config = {
             "Foo Bar": {

From 97bf5cb698bef74da3f51bfe93951235ebf2f3fc Mon Sep 17 00:00:00 2001
From: sundeep8967 <sundeep8967@gmail.com>
Date: Wed, 26 Aug 2026 02:31:07 +0530
Subject: [PATCH 2/5] Add news entry for gh-156353

Signed-off-by: sundeep8967 <sundeep8967@gmail.com>
---
 .../next/Library/2026-08-26-02-30-00.gh-issue-156353.abcdef.rst  | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Library/2026-08-26-02-30-00.gh-issue-156353.abcdef.rst

diff --git a/Misc/NEWS.d/next/Library/2026-08-26-02-30-00.gh-issue-156353.abcdef.rst b/Misc/NEWS.d/next/Library/2026-08-26-02-30-00.gh-issue-156353.abcdef.rst
new file mode 100644
index 000000000000000..9c93abb260e288e
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-08-26-02-30-00.gh-issue-156353.abcdef.rst
@@ -0,0 +1 @@
+Fix :mod:`configparser` space delimiter parsing when using ``delimiters=(' ', '=')``.

From ca0d4f72c80a9235fb82439c984fd422aef4a48c Mon Sep 17 00:00:00 2001
From: sundeep8967 <sundeep8967@gmail.com>
Date: Wed, 26 Aug 2026 03:04:43 +0530
Subject: [PATCH 3/5] test_configparser: allow newconfig to accept **kwargs to
 support custom options

Signed-off-by: sundeep8967 <sundeep8967@gmail.com>
---
 Lib/test/test_configparser.py | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/Lib/test/test_configparser.py b/Lib/test/test_configparser.py
index 7d395232fdc3782..7f0399fd59b96a0 100644
--- a/Lib/test/test_configparser.py
+++ b/Lib/test/test_configparser.py
@@ -43,7 +43,7 @@ class CfgParserTestCaseClass:
     default_section = configparser.DEFAULTSECT
     interpolation = configparser._UNSET
 
-    def newconfig(self, defaults=None):
+    def newconfig(self, defaults=None, **kwargs):
         arguments = dict(
             defaults=defaults,
             allow_no_value=self.allow_no_value,
@@ -56,6 +56,7 @@ def newconfig(self, defaults=None):
             default_section=self.default_section,
             interpolation=self.interpolation,
         )
+        arguments.update(kwargs)
         instance = self.config_class(**arguments)
         return instance
 
@@ -1998,8 +1999,8 @@ class ConvertersTestCase(BasicTestCase, unittest.TestCase):
 
     config_class = configparser.ConfigParser
 
-    def newconfig(self, defaults=None):
-        instance = super().newconfig(defaults=defaults)
+    def newconfig(self, defaults=None, **kwargs):
+        instance = super().newconfig(defaults=defaults, **kwargs)
         instance.converters['list'] = lambda v: [e.strip() for e in v.split()
                                                  if e.strip()]
         return instance

From de81e743b3e1fa466e2d27eb38e9c3d3a6e85f0f Mon Sep 17 00:00:00 2001
From: Petr Viktorin <encukou@gmail.com>
Date: Thu, 27 Aug 2026 13:49:12 +0200
Subject: [PATCH 4/5] Add tests; edit NEWS entry.

---
 Lib/test/test_configparser.py                 | 23 +++++++++++++++++--
 ...-08-26-02-30-00.gh-issue-156353.abcdef.rst |  2 +-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/Lib/test/test_configparser.py b/Lib/test/test_configparser.py
index 7f0399fd59b96a0..7d1e68fe38100ef 100644
--- a/Lib/test/test_configparser.py
+++ b/Lib/test/test_configparser.py
@@ -359,10 +359,29 @@ def test_basic(self):
                 the larch {0[1]} 1
             """.format(self.delimiters)))
 
-    def test_space_delimiter(self):
+    @support.subTests('data', [
+        'foo bar=baz',
+        'foo   bar=baz',
+        'foo=bar=baz',
+        'foo = bar=baz',
+        'foo\t \t=\t \tbar=baz',
+    ])
+    def test_space_delimiter(self, data):
         # gh-156353: Space should be accepted as a delimiter
         cf = self.newconfig(delimiters=(' ', '='))
-        cf.read_string("[all]\nfoo bar=baz")
+        cf.read_string(f"[all]\n{data}")
+        self.assertEqual(cf.options('all'), ['foo'])
+        self.assertEqual(cf.get('all', 'foo'), 'bar=baz')
+
+    @support.subTests('delimiter', ' =:;#x\t\0\N{RS}\N{CEDILLA}\N{CAT}')
+    @support.subTests('space_before', ['', ' ', '\t', ' \t'])
+    @support.subTests('space_after', ['', ' ', '\t', ' \t'])
+    def test_any_delimiter(self, delimiter, space_before, space_after):
+        cf = self.newconfig(
+            delimiters=(delimiter,),
+            inline_comment_prefixes=None,
+        )
+        cf.read_string(f"[all]\nfoo{space_before}{delimiter}{space_after}bar=baz")
         self.assertEqual(cf.options('all'), ['foo'])
         self.assertEqual(cf.get('all', 'foo'), 'bar=baz')
 
diff --git a/Misc/NEWS.d/next/Library/2026-08-26-02-30-00.gh-issue-156353.abcdef.rst b/Misc/NEWS.d/next/Library/2026-08-26-02-30-00.gh-issue-156353.abcdef.rst
index 9c93abb260e288e..0dd925cf596277a 100644
--- a/Misc/NEWS.d/next/Library/2026-08-26-02-30-00.gh-issue-156353.abcdef.rst
+++ b/Misc/NEWS.d/next/Library/2026-08-26-02-30-00.gh-issue-156353.abcdef.rst
@@ -1 +1 @@
-Fix :mod:`configparser` space delimiter parsing when using ``delimiters=(' ', '=')``.
+Fix :mod:`configparser` parsing when using whitespace in *delimiters*.

From 562e043072c6659aaec220da65834a21e0de5464 Mon Sep 17 00:00:00 2001
From: Petr Viktorin <encukou@gmail.com>
Date: Thu, 27 Aug 2026 13:55:02 +0200
Subject: [PATCH 5/5] Word wrap

---
 Lib/configparser.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Lib/configparser.py b/Lib/configparser.py
index 26207fbbdaaf458..88015ef60865698 100644
--- a/Lib/configparser.py
+++ b/Lib/configparser.py
@@ -618,7 +618,8 @@ class RawConfigParser(MutableMapping):
     _OPT_TMPL = r"""
         (?P<option>                        # very permissive!
             (?:(?!{delim})\S)*             # non-delimiter non-whitespace
-            (?:(?:(?!{delim})\s)+(?:(?!{delim})\S)+)*)    # optionally more words
+            (?:(?:(?!{delim})\s)+          # optionally more
+             (?:(?!{delim})\S)+)*)         #   space-separated words
         \s*(?P<vi>{delim})\s*              # any number of space/tab,
                                            # followed by any of the
                                            # allowed delimiters,
@@ -628,7 +629,8 @@ class RawConfigParser(MutableMapping):
     _OPT_NV_TMPL = r"""
         (?P<option>                        # very permissive!
             (?:(?!{delim})\S)*             # non-delimiter non-whitespace
-            (?:(?:(?!{delim})\s)+(?:(?!{delim})\S)+)*)    # optionally more words
+            (?:(?:(?!{delim})\s)+          # optionally more
+             (?:(?!{delim})\S)+)*)         #   space-separated words
         \s*(?:                             # any number of space/tab,
         (?P<vi>{delim})\s*                 # optionally followed by
                                            # any of the allowed