Fix aiohttp 3.14 compatibility (AsyncStreamReaderMixin removed, ClientResponse requires stream_writer)

docs/changelog.rst

@@ -7,6 +7,9 @@ For a full list of triaged issues, bugs and PRs and what release they are target
 
 All help in providing PRs to close out bug issues is appreciated. Even if that is providing a repo that fully replicates issues. We have very generous contributors that have added these to bug issues which meant another contributor picked up the bug and closed it out.
 
+-  8.1.2
+    - Fix aiohttp 3.14 compatibility: ``AsyncStreamReaderMixin`` removed and ``ClientResponse`` now requires ``stream_writer`` (#995) - thanks @dsfaccini
+
 -  8.1.1
     - Fix sync requests in async contexts for HTTPX (#965) - thanks @seowalex
     - CI: bump peter-evans/create-pull-request from 7 to 8 (#969)

tests/integration/aiohttp_utils.py

@@ -18,6 +18,8 @@ async def aiohttp_request(loop, method, url, output="text", encoding="utf-8", co
             content = await response.read()
         elif output == "stream":
             content = await response.content.read()
+        elif output == "stream_chunked":
+            content = b"".join([chunk async for chunk in response.content.iter_chunked(1024)])
 
         response_ctx._resp.close()
         await session.close()

tests/integration/test_aiohttp.py

@@ -137,6 +137,21 @@ def test_stream(tmpdir, httpbin):
         assert cassette.play_count == 1
 
 
+@pytest.mark.online
+def test_stream_chunked(tmpdir, httpbin):
+    # Exercises the async-iteration surface (``content.iter_chunked``) that
+    # ``MockStream`` must keep providing across aiohttp versions.
+    url = httpbin.url
+
+    with vcr.use_cassette(str(tmpdir.join("stream.yaml"))):
+        _, body = get(url, output="raw")  # Do not use stream here, as the stream is exhausted by vcr
+
+    with vcr.use_cassette(str(tmpdir.join("stream.yaml"))) as cassette:
+        _, cassette_body = get(url, output="stream_chunked")
+        assert cassette_body == body
+        assert cassette.play_count == 1
+
+
 POST_DATA = {"key1": "value1", "key2": "value2"}
 
 

vcr/stubs/aiohttp_stubs.py

@@ -2,10 +2,12 @@
 
 import asyncio
 import functools
+import inspect
 import json
 import logging
 from collections.abc import Mapping
 from http.cookies import CookieError, Morsel, SimpleCookie
+from types import SimpleNamespace
 
 from aiohttp import ClientConnectionError, ClientResponse, CookieJar, RequestInfo, hdrs, streams
 from aiohttp.helpers import strip_auth_from_url
@@ -17,13 +19,35 @@
 
 log = logging.getLogger(__name__)
 
+# aiohttp 3.14 made ``stream_writer`` a required ClientResponse argument and,
+# when ``writer`` is None, reads ``stream_writer.output_size``. A replayed
+# response has already been "sent", so a zero-sized writer is accurate. Older
+# aiohttp doesn't accept the argument at all.
+_CLIENT_RESPONSE_PARAMS = inspect.signature(ClientResponse.__init__).parameters
+_CLIENT_RESPONSE_ACCEPTS_STREAM_WRITER = "stream_writer" in _CLIENT_RESPONSE_PARAMS
 
-class MockStream(asyncio.StreamReader, streams.AsyncStreamReaderMixin):
-    pass
+
+class MockStream(asyncio.StreamReader):
+    # aiohttp added the async-iteration helpers below to its response stream via
+    # ``streams.AsyncStreamReaderMixin``, which aiohttp 3.14 removed (folding the
+    # helpers into its own ``StreamReader``). This stub builds on
+    # ``asyncio.StreamReader`` instead, so provide the helpers directly to keep the
+    # streaming surface stable across aiohttp versions.
+    def iter_chunked(self, n):
+        return streams.AsyncStreamIterator(lambda: self.read(n))
+
+    def iter_any(self):
+        return streams.AsyncStreamIterator(self.readany)
+
+    def iter_chunks(self):
+        return streams.ChunkTupleAsyncStreamIterator(self)
 
 
 class MockClientResponse(ClientResponse):
     def __init__(self, method, url, request_info=None):
+        extra = {}
+        if _CLIENT_RESPONSE_ACCEPTS_STREAM_WRITER:
+            extra["stream_writer"] = SimpleNamespace(output_size=0)
         super().__init__(
             method=method,
             url=url,
@@ -34,6 +58,7 @@ def __init__(self, method, url, request_info=None):
             traces=None,
             loop=asyncio.get_event_loop(),
             session=None,
+            **extra,
         )
 
     async def json(self, *, encoding="utf-8", loads=json.loads, **kwargs):