From d1fcdf26ea9e1fcdf9113ee14710ef68ba1fe19c Mon Sep 17 00:00:00 2001
From: tonghuaroot <tonghuaroot@gmail.com>
Date: Mon, 10 Aug 2026 12:19:49 +0800
Subject: [PATCH] gh-155454: Fix platform.libc_ver() crash on threaded libc
 without version

A libc.so match with a thread suffix but no version left ver as None, which was
then subscripted. Guard the check with ver is not None.
---
 Lib/platform.py                                                | 3 ++-
 Lib/test/test_platform.py                                      | 1 +
 .../Library/2026-08-10-12-19-07.gh-issue-155454.Lb7Cq4.rst     | 3 +++
 3 files changed, 6 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Library/2026-08-10-12-19-07.gh-issue-155454.Lb7Cq4.rst

diff --git a/Lib/platform.py b/Lib/platform.py
index 3141998e02dfe21..99fcc75f19b61b0 100644
--- a/Lib/platform.py
+++ b/Lib/platform.py
@@ -240,7 +240,8 @@ def libc_ver(executable=None, lib='', version='', chunksize=16384):
                     lib = 'libc'
                     if soversion and (not ver or V(soversion) > V(ver)):
                         ver = soversion
-                    if threads and ver[-len(threads):] != threads:
+                    if (threads and ver is not None
+                            and ver[-len(threads):] != threads):
                         ver = ver + threads
             elif musl:
                 lib = 'musl'
diff --git a/Lib/test/test_platform.py b/Lib/test/test_platform.py
index 3503eaefaf8e9e7..1ee634189b612bf 100644
--- a/Lib/test/test_platform.py
+++ b/Lib/test/test_platform.py
@@ -576,6 +576,7 @@ def test_libc_ver(self):
                 (b'GLIBC_2.9', ('glibc', '2.9')),
                 (b'libc.so.1.2.5', ('libc', '1.2.5')),
                 (b'libc_pthread.so.1.2.5', ('libc', '1.2.5_pthread')),
+                (b'libc_r.so', ('libc', '')),
                 (b'/aports/main/musl/src/musl-1.2.5', ('musl', '1.2.5')),
                 # musl uses semver, but we accept some variations anyway:
                 (b'/aports/main/musl/src/musl-12.5', ('musl', '12.5')),
diff --git a/Misc/NEWS.d/next/Library/2026-08-10-12-19-07.gh-issue-155454.Lb7Cq4.rst b/Misc/NEWS.d/next/Library/2026-08-10-12-19-07.gh-issue-155454.Lb7Cq4.rst
new file mode 100644
index 000000000000000..6717334161974dc
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-08-10-12-19-07.gh-issue-155454.Lb7Cq4.rst
@@ -0,0 +1,3 @@
+Fix :func:`platform.libc_ver` crashing with :exc:`TypeError` when the scanned
+binary references a threaded C library (such as ``libc_r``) that has no version
+number. Patch by tonghuaroot.