Issue #10601: sys.displayhook uses 'backslashreplace' error handler on

UnicodeEncodeError.

1 files changed, 28 insertions, 2 deletions

diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index c7aa214..95d1cf9 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -99,13 +99,39 @@ always available.
 
 .. function:: displayhook(value)
 
-   If *value* is not ``None``, this function prints it to ``sys.stdout``, and saves
-   it in ``builtins._``.
+   If *value* is not ``None``, this function prints ``repr(value)`` to
+   ``sys.stdout``, and saves *value* in ``builtins._``. If ``repr(value)`` is
+   not encodable to ``sys.stdout.encoding`` with ``sys.stdout.errors`` error
+   handler (which is probably ``'strict'``), encode it to
+   ``sys.stdout.encoding`` with ``'backslashreplace'`` error handler.
 
    ``sys.displayhook`` is called on the result of evaluating an :term:`expression`
    entered in an interactive Python session.  The display of these values can be
    customized by assigning another one-argument function to ``sys.displayhook``.
 
+   Pseudo-code::
+
+       def displayhook(value):
+           if value is None:
+               return
+           # Set '_' to None to avoid recursion
+           builtins._ = None
+           text = repr(value)
+           try:
+               sys.stdout.write(text)
+           except UnicodeEncodeError:
+               bytes = text.encode(sys.stdout.encoding, 'backslashreplace')
+               if hasattr(sys.stdout, 'buffer'):
+                   sys.stdout.buffer.write(bytes)
+               else:
+                   text = bytes.decode(sys.stdout.encoding, 'strict')
+                   sys.stdout.write(text)
+           sys.stdout.write("\n")
+           builtins._ = value
+
+   .. versionchanged:: 3.2
+      Use ``'backslashreplace'`` error handler on :exc:`UnicodeEncodeError`.
+
 
 .. function:: excepthook(type, value, traceback)