#24280 [python] require Python >= 3.10 and restore full dependency floors

Follow-up to #24186 — raise requires-python to >=3.10 and restore the full dependency floors

#24186 raised the generated Python client dependency floors above known-vulnerable ranges, but had to lower three of them to keep the generated clients installable under the declared requires-python:

package	#24186 shipped	fully-patched floor
urllib3	>= 2.6.3, < 3.0.0	>= 2.7.0, < 3.0.0
aiohttp	>= 3.13.5	>= 3.14.1
pytest (dev)	>= 8.4.2	>= 9.0.3

The safest patched releases of these packages are published only for Python ≥ 3.10, so at requires-python = ">=3.9" the resolver would still be free to pick vulnerable versions on 3.9. That left the newest advisories uncleared at the declaration level:

• urllib3 — GHSA-mf9v-mfxr-j63j, GHSA-qccp-gfcp-xxvc (fixed in 2.7.0)
• aiohttp — the <= 3.14.0 advisory batch (fixed in 3.14.1)
• pytest — GHSA-6w46-j5rx-g56g / CVE-2025-71176 (fixed in 9.0.3)

What this PR does

1. Raises requires-python from >=3.9 to >=3.10 in the Python generator templates. This aligns the PEP-621 [project] metadata with the poetry (python = "^3.10") and setup.py (PYTHON_REQUIRES = ">= 3.10") declarations, which already dropped 3.9 in #22926 — the PEP-621 requires-python line was the one spot left at >=3.9.
2. Restores the higher floors (urllib3 >= 2.7.0, aiohttp >= 3.14.1, pytest >= 9.0.3) so the declared ranges fully exclude the vulnerable versions for every supported interpreter.

With the minimum interpreter at 3.10, the restored floors resolve cleanly and the declared ranges no longer admit any of the advisory-affected releases.

Breaking change

Dropping Python 3.9 support from the generated clients is intentional and is the mechanism by which the floors can be raised. Generated-client consumers still on 3.9 would need to stay on an older generator version.

Samples

Regenerated the affected Python client samples (python, python-aiohttp, python-httpx, python-httpx-sync, python-lazyImports, python-echo-api, and the disallowAdditionalPropertiesIfNotPresent echo variant) — the same set touched by #24186. The diff is limited to the floor lines and the requires-python line.

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Summary by cubic

Raise Python requirement for generated Python clients to >=3.10 and restore secure floors for urllib3, aiohttp, and pytest. This aligns PEP-621 metadata with poetry/setup.py and prevents installs from picking vulnerable versions.

• Dependencies

  • urllib3 >= 2.7.0, < 3.0.0
  • aiohttp >= 3.14.1
  • pytest >= 9.0.3 (dev)

• Migration

  • Python 3.9 is no longer supported. Pin to an older generator if you must support 3.9.