From: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Date: Mon, 2 Feb 2026 10:29:16 +0000 (+0100)
Subject: [3.13] gh-144380: Fix incorrect type check in `buffered_iternext()` (GH-144381) ... 
X-Git-Tag: v3.13.12~10
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=51fccc6059d7efb866ddf506d1721bcef8292926;p=thirdparty%2FPython%2Fcpython.git

[3.13] gh-144380: Fix incorrect type check in `buffered_iternext()` (GH-144381) (#144390)

gh-144380: Fix incorrect type check in `buffered_iternext()` (GH-144381)
(cherry picked from commit 40d07cad38bf3ce60f4ca03f1836e8650fe40df5)

Co-authored-by: Ruiyang Ke <me@ry.ke>
---

diff --git a/Misc/NEWS.d/next/Library/2026-02-01-15-25-00.gh-issue-144380.U7py_s.rst b/Misc/NEWS.d/next/Library/2026-02-01-15-25-00.gh-issue-144380.U7py_s.rst
new file mode 100644
index 000000000000..4b5b1b3776d7
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-02-01-15-25-00.gh-issue-144380.U7py_s.rst
@@ -0,0 +1 @@
+Improve performance of :class:`io.BufferedReader` line iteration by ~49%.
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index 65d69d0d5e13..2e8566168de4 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -1486,8 +1486,8 @@ buffered_iternext(buffered *self)
 
     _PyIO_State *state = find_io_state_by_def(Py_TYPE(self));
     tp = Py_TYPE(self);
-    if (Py_IS_TYPE(tp, state->PyBufferedReader_Type) ||
-        Py_IS_TYPE(tp, state->PyBufferedRandom_Type))
+    if (tp == state->PyBufferedReader_Type ||
+        tp == state->PyBufferedRandom_Type)
     {
         /* Skip method call overhead for speed */
         line = _buffered_readline(self, -1);