From d9407b174c81fda33e6c09a6f988c9a7cb8368af Mon Sep 17 00:00:00 2001
From: Stanley <46876382+slateny@users.noreply.github.com>
Date: Fri, 21 Oct 2022 16:01:05 -0700
Subject: gh-51511: Note that codecs.open()'s encoding parameter affects
 automatic conversion to binary mode (#94370)

---
 Doc/library/codecs.rst  | 3 ++-
 Lib/codecs.py           | 3 ++-
 Lib/test/test_codecs.py | 3 ++-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/Doc/library/codecs.rst b/Doc/library/codecs.rst
index 4a665f2..8225236 100644
--- a/Doc/library/codecs.rst
+++ b/Doc/library/codecs.rst
@@ -189,7 +189,8 @@ wider range of codecs when working with binary files:
 
    .. note::
 
-      Underlying encoded files are always opened in binary mode.
+      If *encoding* is not ``None``, then the
+      underlying encoded files are always opened in binary mode.
       No automatic conversion of ``'\n'`` is done on reading and writing.
       The *mode* argument may be any binary mode acceptable to the built-in
       :func:`open` function; the ``'b'`` is automatically added.
diff --git a/Lib/codecs.py b/Lib/codecs.py
index 5a1e7ec..c1c55d8 100644
--- a/Lib/codecs.py
+++ b/Lib/codecs.py
@@ -878,7 +878,8 @@ def open(filename, mode='r', encoding=None, errors='strict', buffering=-1):
         codecs. Output is also codec dependent and will usually be
         Unicode as well.
 
-        Underlying encoded files are always opened in binary mode.
+        If encoding is not None, then the
+        underlying encoded files are always opened in binary mode.
         The default file mode is 'r', meaning to open the file in read mode.
 
         encoding specifies the encoding which is to be used for the
diff --git a/Lib/test/test_codecs.py b/Lib/test/test_codecs.py
index 57f3648..32a704f 100644
--- a/Lib/test/test_codecs.py
+++ b/Lib/test/test_codecs.py
@@ -708,7 +708,8 @@ class UTF16Test(ReadTest, unittest.TestCase):
                                          "spamspam", self.spambe)
 
     def test_bug691291(self):
-        # Files are always opened in binary mode, even if no binary mode was
+        # If encoding is not None, then
+        # files are always opened in binary mode, even if no binary mode was
         # specified.  This means that no automatic conversion of '\n' is done
         # on reading and writing.
         s1 = 'Hello\r\nworld\r\n'
-- 
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