Fix async life cycle management to prevent lost references to tasks. - #157

[sebastiaan-la-fleur]

PR does 2 things:

• Fix CI
• Fix lifecycle management for async tasks in the AsyncConnection class so task references do not get lost due to exceptions and cancellations.

[sebastiaan-la-fleur]

Sorry for also fixing CI in this PR, but we were running into some annoying issues that prevented the actual fix from succeeding in CI.

[Copilot]

Note

Copilot was unable to run its full agentic suite in this review.

Copilot review overview

Review effort: Lite
Findings: 4

Open (4)

• Unquoted $@ will word-split and glob-expand arguments (breaking flags that contain spaces and… · New
• asyncio.get_event_loop() is deprecated in some contexts and can behave differently across Python… · New
• This overwrites any existing PYTHONPATH in the environment, which can break developer/CI setups… · New
• With multiple pylint commands, tox will stop at the first failure, which can hide additional lint… · New

What changed in this PR

Updates the async connection’s task-lifecycle handling and expands the project’s quality gates (lint/typecheck/CI) while adding targeted unit tests to validate cancellation/stop/exception behavior.

Changes:

• Refactors S2AsyncConnection.run() and send_msg_and_await_reception_status() to more reliably cancel/drain background tasks and surface/log exceptions.
• Adds new async connection lifecycle unit tests and tweaks existing unit-test formatting.
• Expands tooling: runs pyright in typecheck, adjusts lint configuration for tests, and refactors GitHub Actions CI into a reusable workflow.

File	Description
tox.ini	Adjusts lint/typecheck commands; adds PYTHONPATH for lint; runs pyright in tox typecheck env.
tests/​unit/​reception_status_awaiter_test.py	Reformats list comprehensions for readability.
tests/​unit/​connection/​async_/​connection_test.py	Adds new unit tests covering async connection task management and cancellation/stop scenarios.
src/​s2python/​connection/​async_/​connection.py	Refactors background task creation/cancellation/draining and exception logging.
pyrightconfig.json	Adds a tests execution environment and relaxes a specific diagnostic for tests.
pyproject.toml	Raises minimum setuptools version.
mypy.ini	Disables additional mypy error codes for a test-related section.
dev-requirements.txt	Regenerates dev requirements (Python 3.9) and adds backports needed for older runtimes.
ci/​typecheck.sh	Aggregates mypy + pyright exit status so both run and report failures.
ci/​test_unit.sh	Allows passing through extra pytest args.
ci/​setup_dev_environment.sh	Switches venv creation to Python 3.9.
ci/​lint.sh	Splits linting for src/examples vs tests with different pylint settings.
AGENTS.md	Adds contributor/development guidelines and tooling conventions.
.pylintrc	Keeps certain checks enabled globally; relies on entry points to disable for tests.
.github/​workflows/​ci.yml	Replaces per-job definitions with a reusable workflow and updates publish jobs.
.github/​workflows/​check-python.yml	New reusable workflow to build/test/lint/typecheck per Python version.

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