gh-89268: Escape RTL characters in str.__repr__()

Previously, non-escaped right-to-left characters caused misleading
output on Unicode-aware terminals and browsers.
Correspondingly, str.isprintable() now returns False for such
characters.

Author: serhiy-storchaka

Doc/library/stdtypes.rst

@@ -2330,6 +2330,8 @@ expression support in the :mod:`re` module).
    Number, Punctuation, or Symbol (L, M, N, P, or S); plus the ASCII space 0x20.
    Nonprintable characters are those in group Separator or Other (Z or C),
    except the ASCII space.
+   Additionally, strong right-to-left characters which have a bidirectional
+   class R or AL considered non-printable.
 
    For example:
 
@@ -2339,6 +2341,11 @@ expression support in the :mod:`re` module).
       (True, True)
       >>> '\t'.isprintable(), '\n'.isprintable()
       (False, False)
+      >>> '\u05be'.isprintable(), '\u0608'.isprintable()
+      (False, False)
+
+   .. versionchanged:: next
+      Strong right-to-left characters considered non-printable.
 
 
 .. method:: str.isspace()

Doc/whatsnew/3.15.rst

@@ -426,6 +426,14 @@ Other language changes
   controlled by :ref:`environment variables <using-on-controlling-color>`.
   (Contributed by Peter Bierma in :gh:`134170`.)
 
+* The :meth:`~object.__repr__` of :class:`str` now hex-escapes strong
+  right-to-left characters (bidirectional class R and AL).
+  Previously, non-escaped right-to-left characters caused misleading
+  output on Unicode-aware terminals and browsers.
+  Correspondingly, :meth:`str.isprintable` now returns ``False`` for such
+  characters.
+  (Contributed by Serhiy Storchaka in :gh:`89268`.)
+
 * The :meth:`~object.__repr__` of :class:`ImportError` and :class:`ModuleNotFoundError`
   now shows "name" and "path" as ``name=<name>`` and ``path=<path>`` if they were given
   as keyword arguments at construction time.

Lib/test/test_str.py

@@ -853,6 +853,12 @@ def test_isprintable(self):
         self.assertTrue('\U0001F46F'.isprintable())
         self.assertFalse('\U000E0020'.isprintable())
 
+        # strong right-to-left character
+        self.assertFalse("\u05be".isprintable())
+        self.assertFalse("\u0608".isprintable())
+        self.assertFalse("\U00010800".isprintable())
+        self.assertFalse("\U00010d00".isprintable())
+
     @support.requires_resource('cpu')
     def test_isprintable_invariant(self):
         for codepoint in range(sys.maxunicode + 1):

Misc/NEWS.d/next/Core_and_Builtins/2026-02-12-14-14-48.gh-issue-89268.AlK3IE.rst

@@ -0,0 +1,5 @@
+The :meth:`~object.__repr__` of :class:`str` now hex-escapes strong
+right-to-left characters (bidirectional class R and AL). Previously,
+non-escaped right-to-left characters caused misleading output on
+Unicode-aware terminals and browsers. Correspondingly,
+:meth:`str.isprintable` now returns ``False`` for such characters.