[PR #12629/66cc7b68 backport][3.13] Install Python via astral-sh/setup-uv in test/autobahn jobs

[bdraco]

This is a backport of PR #12629 as merged into master (66cc7b6).

What do these changes do?

Swap actions/setup-python@v6 for astral-sh/setup-uv@v8.1.0 in
the two CI matrix jobs that install a Python interpreter — test
and autobahn. activate-environment: true keeps python/pip
on PATH so the subsequent uv pip install ... invocations target
the seeded venv. enable-cache: true subsumes the previous
actions/cache pip-cache step, which is dropped.

Are there changes in behavior for the user?

No. This only affects CI runner provisioning. End-user-visible
behavior of aiohttp is unaffected.

The Codecov flag derived from
steps.python-install.outputs.python-version now reports the
matrix spec (3.14t) rather than the resolved patch
(3.14.5t); coarser, but easier to group across patch releases.

Is it a substantial burden for the maintainers to support this?

No. astral-sh/setup-uv is widely used across aio-libs and the
broader Python ecosystem; activate-environment: true reproduces
the behavior the existing pipeline already relies on, so the swap
is local to the action invocation.

This mirrors aio-libs/yarl#1704, which made the same swap.

Related issue number

N/A.

Checklist

• I think the code is well written
• Unit tests for the changes exist — N/A (CI configuration)
• Documentation reflects the changes — N/A (no user-visible change)
• If you provide code modification, please add yourself to CONTRIBUTORS.txt — already listed
• Add a new news fragment into the CHANGES/ folder — to be added in a follow-up commit once the PR number is assigned

Agent run details (optional, for reviewers)

actions/setup-python downloads non-cached interpreter variants
from its release index, which takes ~40s on macos-latest and ~58s
on windows-latest for 3.14t (the free-threaded build is not in
the hosted-tool-cache). astral-sh/setup-uv pulls
python-build-standalone from a CDN, which is a few seconds across
all three OSes. Motivation transferred from the yarl PR's own
measurements.

Drafted with Claude Code (Opus 4.7); reviewed by @bdraco.

[codecov]

❌ 1 Tests Failed:

Tests completed	Failed	Passed	Skipped
4383	1	4382	81

View the top 1 failed test(s) by shortest run time

tests.test_web_urldispatcher::test_access_symlink_loop[pyloop]

Stack Traces | 0.206s run time

tmp_path = WindowsPath('C:.../pytest-0/popen-gw2/test_access_symlink_loop_pyloo0')
aiohttp_client = <function aiohttp_client.<locals>.go at 0x000001EC6CF8A9D0>

    #x1B[0m#x1B[94masync#x1B[39;49;00m #x1B[94mdef#x1B[39;49;00m#x1B[90m #x1B[39;49;00m#x1B[92mtest_access_symlink_loop#x1B[39;49;00m(#x1B[90m#x1B[39;49;00m
        tmp_path: pathlib.Path, aiohttp_client: AiohttpClient#x1B[90m#x1B[39;49;00m
    ) -> #x1B[94mNone#x1B[39;49;00m:#x1B[90m#x1B[39;49;00m
        #x1B[90m# Tests the access to a looped symlink, which could not be resolved.#x1B[39;49;00m#x1B[90m#x1B[39;49;00m
        my_dir_path = tmp_path / #x1B[33m"#x1B[39;49;00m#x1B[33mmy_symlink#x1B[39;49;00m#x1B[33m"#x1B[39;49;00m#x1B[90m#x1B[39;49;00m
        pathlib.Path(#x1B[96mstr#x1B[39;49;00m(my_dir_path)).symlink_to(#x1B[96mstr#x1B[39;49;00m(my_dir_path), #x1B[94mTrue#x1B[39;49;00m)#x1B[90m#x1B[39;49;00m
    #x1B[90m#x1B[39;49;00m
        app = web.Application()#x1B[90m#x1B[39;49;00m
    #x1B[90m#x1B[39;49;00m
        #x1B[90m# Register global static route:#x1B[39;49;00m#x1B[90m#x1B[39;49;00m
        app.router.add_static(#x1B[33m"#x1B[39;49;00m#x1B[33m/#x1B[39;49;00m#x1B[33m"#x1B[39;49;00m, #x1B[96mstr#x1B[39;49;00m(tmp_path), show_index=#x1B[94mTrue#x1B[39;49;00m)#x1B[90m#x1B[39;49;00m
        client = #x1B[94mawait#x1B[39;49;00m aiohttp_client(app)#x1B[90m#x1B[39;49;00m
    #x1B[90m#x1B[39;49;00m
        #x1B[90m# Request the root of the static directory.#x1B[39;49;00m#x1B[90m#x1B[39;49;00m
        r = #x1B[94mawait#x1B[39;49;00m client.get(#x1B[33m"#x1B[39;49;00m#x1B[33m/#x1B[39;49;00m#x1B[33m"#x1B[39;49;00m + my_dir_path.name)#x1B[90m#x1B[39;49;00m
>       #x1B[94massert#x1B[39;49;00m r.status == #x1B[94m404#x1B[39;49;00m#x1B[90m#x1B[39;49;00m
#x1B[1m#x1B[31mE       AssertionError: assert 500 == 404#x1B[0m
#x1B[1m#x1B[31mE        +  where 500 = <ClientResponse(http://127.0.0.1:51758/my_symlink) [500 Internal Server Error]>\n<CIMultiDictProxy('Content-Type': 'text/plain; charset=utf-8', 'Content-Length': '55', 'Date': 'Tue, 19 May 2026 18:08:48 GMT', 'Server': 'Python/3.9 aiohttp/3.13.5.dev0', 'Connection': 'close')>\n.status#x1B[0m

aiohttp_client = <function aiohttp_client.<locals>.go at 0x000001EC6CF8A9D0>
app        = <Application 0x1ec6cf66fa0>
client     = <aiohttp.test_utils.TestClient object at 0x000001EC6CF66190>
my_dir_path = WindowsPath('C:.../pytest-0/popen-gw2/test_access_symlink_loop_pyloo0/my_symlink')
r          = <ClientResponse(http://127.0.0.1:51758/my_symlink) [500 Internal Server Error]>
<CIMultiDictProxy('Content-Type': 'tex...h': '55', 'Date': 'Tue, 19 May 2026 18:08:48 GMT', 'Server': 'Python/3.9 aiohttp/3.13.5.dev0', 'Connection': 'close')>

tmp_path   = WindowsPath('C:.../pytest-0/popen-gw2/test_access_symlink_loop_pyloo0')

#x1B[1m#x1B[31mtests\test_web_urldispatcher.py#x1B[0m:540: AssertionError

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[codspeed-hq]

Merging this PR will not alter performance

✅ 66 untouched benchmarks

---

_{Comparing bdraco:patchback/backports/3.13/66cc7b68aad1ca084d210a466d4970de9619f10e/pr-12629 (dd8b34b) with 3.13 (4ec3ac3)}

[bdraco]

need to dig in to the test failure more.

[Dreamsorcerer]

Don't need 3.13 backport anymore.