[3.12] gh-78889: Stop IDLE Shell freezes from sys.stdout.shell.xyz (GH-121876) (#121912)

miss-islington · terryjreedy · web-flow · commit a6516de08b70 · 2024-07-17T14:03:54.000Z
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 58753f3) Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
diff --git 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
@@ -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
@@ -0,0 +1,2 @@
+Stop Shell freezes by blocking user access to non-method sys.stdout.shell attributes,
+which are all private.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+Stop Shell freezes by blocking user access to non-method sys.stdout.shell attributes,`
	`2`	`+which are all private.`