#55 fix(ci): tomllib is not stdlib below Python 3.11, but the test matrix runs 3.9

User description

What

pytest collection failed on the Python 3.9 leg of python-tests.yml with:

ModuleNotFoundError: No module named 'tomllib'

for both tests/test_check_drift.py and tests/test_ga_common_github_auth.py, interrupting the whole run on that matrix leg (2 errors during collection, 0 tests executed).

Root cause

tomllib is Python stdlib only from 3.11. This package declares requires-python = ">=3.9" and python-tests.yml's matrix is ["3.9", "3.12", "3.13"] — deliberately added so a version that can install the wheel is also a version whose behavior is asserted. pytest collects every test file in the run regardless of which one is under test, so any file that imports a module doing import tomllib unconditionally breaks collection for the entire 3.9 leg, not just its own tests.

Two release-tooling modules had this: scripts/release/check_drift.py and scripts/ga/ga_common.py. Both did import tomllib unconditionally, even though pyproject.toml already declares "tomli>=2.0.0; python_version < '3.11'" as a dev extra specifically for this case, and tests/test_packaging.py already carries the correct fallback pattern (comment: "tomllib is stdlib from 3.11 only"). These two modules were simply never updated to match.

Fix

Applied the exact same, already-established pattern from tests/test_packaging.py to both modules:

try:  # tomllib is stdlib from 3.11; `tomli` is a dev dependency below that (see pyproject.toml).
    import tomllib
except ModuleNotFoundError:
    import tomli as tomllib

Also updated check_drift.py's module docstring, which claimed "Python 3.11+ ... required" — that was never actually a hard requirement given the tomli extra, and the CI matrix now proves it isn't.

Verification

• python3 -m py_compile on both changed files: clean.
• Simulated ModuleNotFoundError for tomllib via a monkeypatched __import__ and imported check_drift fresh: it fell through to tomli correctly (check_drift.tomllib resolved to the tomli module object).
• python3 -m pytest -q tests/test_check_drift.py tests/test_ga_common_github_auth.py: 13 passed, 0 failed (run on the locally available Python 3.14, which already had tomllib; the fallback path itself was proven separately above since no 3.9 interpreter was available in this environment).
• No 3.9 interpreter was available in the sandbox this fix was authored in, so the CI matrix itself is the first real 3.9 execution — the change is a minimal, mechanical mirror of test_packaging.py's already-shipped and already-tested pattern, not new untested logic.

Scope

Two files touched, both additive (a try/except ModuleNotFoundError wrapper around an existing single-line import, plus one docstring correction). No test was weakened, skipped, or had an assertion loosened — this fixes test collection, which is a strict net-positive for coverage (0 tests running on 3.9 -> all tests running on 3.9).

Context

This was investigated as part of a fleet-wide sweep for CI failures across the ~32 WAVE public repos. Measuring gh run list --branch main across every public repo found that only this repo had a genuine current failure on its default branch. sdks' concurrent registry clean-room acceptance failures had already self-resolved (green as of the latest run) before this sweep started. This fix addresses the one real, currently-reproducing failure found, with its own distinct root cause (a Python stdlib version gate, unrelated to any Node/npm NODE_ENV install-skip pattern floated as a leading hypothesis for a fleet-wide story).

^{Need help on this PR? Tag @codesmith-bot with what you need. Autofix is disabled.}

[!NOTE]
Low Risk
Additive import compatibility only; no logic or assertion changes beyond enabling the 3.9 CI matrix leg to collect and run tests.

Overview
Fixes pytest collection on Python 3.9 by stopping unconditional import tomllib in scripts/ga/ga_common.py and scripts/release/check_drift.py. Both now use the same try stdlib tomllib / except tomli as tomllib pattern already used elsewhere in the repo, aligned with the existing tomli dev extra for python_version < '3.11'.

check_drift.py's module docstring is updated to describe 3.9+ support (via tomli) instead of implying Python 3.11+ only. Behavior for reading pyproject.toml is unchanged on 3.11+; on 3.9–3.10 imports no longer fail at module load time.

^{Reviewed by Cursor Bugbot for commit 62f870604c5563ea78a82f719b4048d7cf1d2133. Bugbot is set up for automated code reviews on this repo. Configure here.}

Summary by Sourcery

Support TOML parsing across all supported Python versions so the complete test suite can run on Python 3.9.

Bug Fixes:

• Restore Python 3.9 CI test collection by falling back to the supported tomli package when tomllib is unavailable.

Enhancements:

• Update release tooling documentation to reflect support across the package’s Python 3.9+ compatibility matrix.

CodeAnt-AI Description

Restore Python 3.9 compatibility for release tooling

What Changed

• Release and GA tooling now reads project metadata on Python versions below 3.11 using the supported TOML compatibility package
• Python 3.9 test collection no longer fails when these modules are imported
• Documentation now reflects support for the full Python 3.9+ compatibility range

Impact

✅ Passing Python 3.9 test runs
✅ Fewer CI collection failures
✅ Release checks work across supported Python versions

@codeant-ai ask: Your question here

@codeant-ai ask: Can you suggest a safer alternative to storing this secret?

@codeant-ai: Your feedback here

@codeant-ai: Do not flag unused imports.

@codeant-ai: review