Swap around __bytes__/__str__ for some classes

Plus related updates to tests, docstrings, changelog

4 files changed, 17 insertions, 5 deletions

diff --git a/paramiko/message.py b/paramiko/message.py
index d02f7855..cdefe4f8 100644
--- a/paramiko/message.py
+++ b/paramiko/message.py
@@ -54,10 +54,7 @@ class Message(object):
         else:
             self.packet = BytesIO()
 
-    def __str__(self):
-        """
-        Return the byte stream content of this message, as a string/bytes obj.
-        """
+    def __bytes__(self):
         return self.asbytes()
 
     def __repr__(self):
diff --git a/paramiko/pkey.py b/paramiko/pkey.py
index 058d1258..d5ea27b6 100644
--- a/paramiko/pkey.py
+++ b/paramiko/pkey.py
@@ -110,6 +110,7 @@ class PKey(object):
         """
         pass
 
+    # TODO 4.0: just merge into __bytes__ (everywhere)
     def asbytes(self):
         """
         Return a string of an SSH `.Message` made up of the public part(s) of
@@ -118,7 +119,7 @@ class PKey(object):
         """
         return bytes()
 
-    def __str__(self):
+    def __bytes__(self):
         return self.asbytes()
 
     # noinspection PyUnresolvedReferences
diff --git a/sites/www/changelog.rst b/sites/www/changelog.rst
index 595e2fde..63cb6d60 100644
--- a/sites/www/changelog.rst
+++ b/sites/www/changelog.rst
@@ -2,6 +2,14 @@
 Changelog
 =========
 
+- :bug:`- major` A handful of lower-level classes (notably
+  `paramiko.message.Message` and `paramiko.pkey.PKey`) previously returned
+  `bytes` objects from their implementation of ``__str__``, even under Python
+  3; and there was never any ``__bytes__`` method.
+
+  These issues have been fixed by renaming ``__str__`` to ``__bytes__`` and
+  relying on Python's default "stringification returns the output of
+  ``__repr__``" behavior re: any real attempts to ``str()`` such objects.
 - :support:`-` ``paramiko.common.asbytes`` has been moved to
   `paramiko.util.asbytes`.
 
diff --git a/tests/test_message.py b/tests/test_message.py
index bd2d5795..3c5f961b 100644
--- a/tests/test_message.py
+++ b/tests/test_message.py
@@ -105,3 +105,9 @@ class MessageTest(unittest.TestCase):
         self.assertEqual(msg.get_adaptive_int(), 5)
         self.assertEqual(msg.get_so_far(), self.__d[:4])
         self.assertEqual(msg.get_remainder(), self.__d[4:])
+
+    def test_bytes_str_and_repr(self):
+        msg = Message(self.__d)
+        assert str(msg) == f"paramiko.Message({self.__d!r})"
+        assert repr(msg) == str(msg)
+        assert bytes(msg) == msg.asbytes() == self.__d