From ce8bce4099867f7f7902d55c0137c76750a142bd Mon Sep 17 00:00:00 2001
From: Terry Jan Reedy <tjreedy@udel.edu>
Date: Wed, 17 Jul 2024 09:33:33 -0400
Subject: [PATCH] gh-78889: Stop IDLE Shell freezes from sys.stdout.shell.xyz
 (GH-121876)

Problem occurred when attribute xyz could not be pickled.
Since this is not trivial to selectively fix, block all
attributes (other than 'width').  IDLE does not access them
and they are private implementation details.
(cherry picked from commit 58753f33e47fe48906883dc010771f68c13b7e52)

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
---
 Lib/idlelib/News3.txt                                          | 3 +++
 Lib/idlelib/run.py                                             | 3 +++
 .../next/IDLE/2024-07-16-16-57-03.gh-issue-78889.U7ghFD.rst    | 2 ++
 3 files changed, 8 insertions(+)
 create mode 100644 Misc/NEWS.d/next/IDLE/2024-07-16-16-57-03.gh-issue-78889.U7ghFD.rst

diff --git a/Lib/idlelib/News3.txt b/Lib/idlelib/News3.txt
index c92196f1f4a642..39791d60c06829 100644
--- a/Lib/idlelib/News3.txt
+++ b/Lib/idlelib/News3.txt
@@ -4,6 +4,9 @@ Released after 2023-10-02
 =========================
 
 
+gh-78889: Stop Shell freezes by blocking user access to non-method
+sys.stdout.shell attributes, which are all private.
+
 gh-78955: Use user-selected color theme for Help => IDLE Doc.
 
 gh-96905: In idlelib code, stop redefining built-ins 'dict' and 'object'.
diff --git a/Lib/idlelib/run.py b/Lib/idlelib/run.py
index 53e80a9b42801f..476a7b26c004b5 100644
--- a/Lib/idlelib/run.py
+++ b/Lib/idlelib/run.py
@@ -436,6 +436,9 @@ class StdioFile(io.TextIOBase):
 
     def __init__(self, shell, tags, encoding='utf-8', errors='strict'):
         self.shell = shell
+        # GH-78889: accessing unpickleable attributes freezes Shell.
+        # IDLE only needs methods; allow 'width' for possible use.
+        self.shell._RPCProxy__attributes = {'width': 1}
         self.tags = tags
         self._encoding = encoding
         self._errors = errors
diff --git a/Misc/NEWS.d/next/IDLE/2024-07-16-16-57-03.gh-issue-78889.U7ghFD.rst b/Misc/NEWS.d/next/IDLE/2024-07-16-16-57-03.gh-issue-78889.U7ghFD.rst
new file mode 100644
index 00000000000000..604194ebb2e859
--- /dev/null
+++ b/Misc/NEWS.d/next/IDLE/2024-07-16-16-57-03.gh-issue-78889.U7ghFD.rst
@@ -0,0 +1,2 @@
+Stop Shell freezes by blocking user access to non-method sys.stdout.shell attributes,
+which are all private.