From 0882b73ef3d1ab939672f586f48203bae8d6f79b Mon Sep 17 00:00:00 2001
From: Prafyl <86287866+Prafyl@users.noreply.github.com>
Date: Thu, 1 Oct 2026 17:04:57 +0545
Subject: [PATCH] gh-158560: Quote values in netrc.__repr__() so the output can
 be parsed back

---
 Lib/netrc.py                                       | 13 ++++++++++---
 Lib/test/test_netrc.py                             | 14 ++++++++++++++
 .../2026-10-01-11-19-57.gh-issue-158560.IEhNAe.rst |  3 +++
 3 files changed, 27 insertions(+), 3 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2026-10-01-11-19-57.gh-issue-158560.IEhNAe.rst

diff --git a/Lib/netrc.py b/Lib/netrc.py
index 67a287237cbf8b..1c70aa1744fdaa 100644
--- a/Lib/netrc.py
+++ b/Lib/netrc.py
@@ -77,6 +77,13 @@ def push_token(self, token):
         self.pushback.append(token)
 
 
+def _quote(token):
+    """Quote a token so that _netrclex reads back the same value."""
+    if token and not any(ch in token for ch in ' \t\r\n"\\'):
+        return token
+    return '"' + token.replace('\\', '\\\\').replace('"', '\\"') + '"'
+
+
 class netrc:
     def __init__(self, file=None):
         default_netrc = file is None
@@ -190,10 +197,10 @@ def __repr__(self):
         rep = ""
         for host in self.hosts.keys():
             attrs = self.hosts[host]
-            rep += f"machine {host}\n\tlogin {attrs[0]}\n"
+            rep += f"machine {_quote(host)}\n\tlogin {_quote(attrs[0])}\n"
             if attrs[1]:
-                rep += f"\taccount {attrs[1]}\n"
-            rep += f"\tpassword {attrs[2]}\n"
+                rep += f"\taccount {_quote(attrs[1])}\n"
+            rep += f"\tpassword {_quote(attrs[2])}\n"
         for macro in self.macros.keys():
             rep += f"macdef {macro}\n"
             for line in self.macros[macro]:
diff --git a/Lib/test/test_netrc.py b/Lib/test/test_netrc.py
index bbb49bf15ce8f1..1816a1f2238a1c 100644
--- a/Lib/test/test_netrc.py
+++ b/Lib/test/test_netrc.py
@@ -38,6 +38,20 @@ def test_toplevel_tokens(self):
         self.assertEqual(nrc.hosts['host.domain.com'], ('log1', 'acct1', 'pass1'))
         self.assertEqual(nrc.hosts['default'], ('log2', 'acct2', 'pass2'))
 
+    def test_repr_roundtrip(self):
+        # __repr__() writes the data in .netrc format, so parsing its output
+        # should give back the same entries.
+        values = ['pass', 'pass word', ' pass', 'pass\tword', 'pass\nword',
+                  'pass"word', 'pass\\word', '']
+        for value in values:
+            with self.subTest(value=value):
+                nrc = self.make_nrc("""\
+                    machine host.domain.com login log password pass
+                    """)
+                nrc.hosts['host.domain.com'] = (value, 'acct', value)
+                nrc2 = self.make_nrc(repr(nrc))
+                self.assertEqual(nrc2.hosts, nrc.hosts)
+
     def test_macros(self):
         data = """\
             macdef macro1
diff --git a/Misc/NEWS.d/next/Library/2026-10-01-11-19-57.gh-issue-158560.IEhNAe.rst b/Misc/NEWS.d/next/Library/2026-10-01-11-19-57.gh-issue-158560.IEhNAe.rst
new file mode 100644
index 00000000000000..9b514031f50431
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-10-01-11-19-57.gh-issue-158560.IEhNAe.rst
@@ -0,0 +1,3 @@
+Fix :meth:`!netrc.netrc.__repr__` writing values without quotes, so that an
+empty value or one containing whitespace, a quote or a backslash could not be
+parsed back correctly.