From 68fcb958eb0c023cb895217fdf384206b09d12e8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Denizhan=20Dak=C4=B1l=C4=B1r?= <denizhandakilirn@gmail.com>
Date: Mon, 5 Jan 2026 07:39:11 +0300
Subject: [PATCH] gh-143082: Make readline work when sys.stdin is explicitly
 passed to pdb (#143083)

---
 Lib/pdb.py                                                      | 2 +-
 .../next/Windows/2025-12-25-00-38-20.gh-issue-143082.CYUeux.rst | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Windows/2025-12-25-00-38-20.gh-issue-143082.CYUeux.rst

diff --git a/Lib/pdb.py b/Lib/pdb.py
index eee0273fdc463f..0464b288ef825a 100644
--- a/Lib/pdb.py
+++ b/Lib/pdb.py
@@ -364,7 +364,7 @@ def __init__(self, completekey='tab', stdin=None, stdout=None, skip=None,
         bdb.Bdb.__init__(self, skip=skip, backend=backend if backend else get_default_backend())
         cmd.Cmd.__init__(self, completekey, stdin, stdout)
         sys.audit("pdb.Pdb")
-        if stdin:
+        if stdin is not None and stdin is not sys.stdin:
             self.use_rawinput = False
         self.prompt = '(Pdb) '
         self.aliases = {}
diff --git a/Misc/NEWS.d/next/Windows/2025-12-25-00-38-20.gh-issue-143082.CYUeux.rst b/Misc/NEWS.d/next/Windows/2025-12-25-00-38-20.gh-issue-143082.CYUeux.rst
new file mode 100644
index 00000000000000..0652c4ca930027
--- /dev/null
+++ b/Misc/NEWS.d/next/Windows/2025-12-25-00-38-20.gh-issue-143082.CYUeux.rst
@@ -0,0 +1 @@
+Fix :mod:`pdb` arrow key history not working when ``stdin`` is ``sys.stdin``.