asyncio.BaseProactorEventLoop feeds bytearray objects to the Protocol.data_received callback, contradicting docs

[jonathanslenders]

Bug report

Bug description:

The documentation says: https://docs.python.org/3/library/asyncio-protocol.html#asyncio.Protocol.data_received :

Called when some data is received. data is a non-empty bytes object containing the incoming data.

So, it says it should be a bytes object. However:

• First, self._data is a bytearray here:

  cpython/Lib/asyncio/proactor_events.py

  Line 191 in f8a736b

  self._data = bytearray(buffer_size)

• This gets passed to `self._data_received here:

  cpython/Lib/asyncio/proactor_events.py

  Line 230 in f8a736b

  self._loop.call_soon(self._data_received, self._data[:length], length)

• The passed into Protocol.data_received here:

  cpython/Lib/asyncio/proactor_events.py

  Line 274 in f8a736b

  self._protocol.data_received(data)

So, there we get a bytearray object.

This conflicts with the current type hints from typeshed: https://github.com/python/typeshed/blob/main/stdlib/asyncio/protocols.pyi#L14 as well as with the docs.

Is this intentional or not?

The patch is simple:

--- a/Lib/asyncio/proact
+++ b/Lib/asyncio/proactor_events.py
@@ -271,7 +271,7 @@ def _data_received(self, data, length):
                                   'call failed.')
                 return
         else:
-            self._protocol.data_received(data)
+            self._protocol.data_received(bytes(data))

     def _loop_reading(s
         length = -1

Related typeshed issue: python/typeshed#12606

CPython versions tested on:

3.13

Operating systems tested on:

Windows

[jonathanslenders]

Actually, maybe it's a duplicate of: #99941

[jonathanslenders]

Closing this. Apparently it was fixed in v3.12.0a thanks to 1bb68ba

[agronholm]

I can still reproduce this with 3.12.5.