gh-143082: Make readline work when sys.stdin is explicitly passed to pdb (#143083)

Author: zelosleone

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 = {}

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``.