From b807577da257ba2475abe955120fb7bdf739875c Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <solipsis@pitrou.net>
Date: Thu, 27 Feb 2014 22:14:31 +0100
Subject: [PATCH] Issue #20791: copy.copy() now doesn't make a copy when the
 input is a bytes object.  Initial patch by Peter Otten.

---
 Lib/copy.py           | 2 +-
 Lib/test/test_copy.py | 1 +
 Misc/NEWS             | 3 +++
 3 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/Lib/copy.py b/Lib/copy.py
index d26bcdbff6a..bb8840ed549 100644
--- a/Lib/copy.py
+++ b/Lib/copy.py
@@ -110,7 +110,7 @@ _copy_dispatch = d = {}
 def _copy_immutable(x):
     return x
 for t in (type(None), int, float, bool, str, tuple,
-          frozenset, type, range,
+          bytes, frozenset, type, range,
           types.BuiltinFunctionType, type(Ellipsis),
           types.FunctionType, weakref.ref):
     d[t] = _copy_immutable
diff --git a/Lib/test/test_copy.py b/Lib/test/test_copy.py
index cde0baecad6..eb8d18cf0b1 100644
--- a/Lib/test/test_copy.py
+++ b/Lib/test/test_copy.py
@@ -98,6 +98,7 @@ class TestCopy(unittest.TestCase):
             pass
         tests = [None, 42, 2**100, 3.14, True, False, 1j,
                  "hello", "hello\u1234", f.__code__,
+                 b"world", bytes(range(256)),
                  NewStyle, range(10), Classic, max, WithMetaclass]
         for x in tests:
             self.assertIs(copy.copy(x), x)
diff --git a/Misc/NEWS b/Misc/NEWS
index f6d82e24b65..4c99dd33945 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -26,6 +26,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #20791: copy.copy() now doesn't make a copy when the input is
+  a bytes object.  Initial patch by Peter Otten.
+
 - Issue #20621: Fixes a zipimport bug introduced in 3.3.4 that could cause
   spurious crashes or SystemErrors when importing modules or packages from a
   zip file.  The change causing the problem was reverted.