[LJK-ikun]

📥 Pull Request

📘 Description

Closes #1473.

An instrumented executor reused across requests keeps the context captured when the pool was created. Worker spans can therefore attach to an old trace instead of the request active at submission. A task's ContextVar writes also remain visible to the next task on the same worker.

Capture a fresh context on each submit and execute the callable through that context's run. This fixes request parentage and isolates task-local writes, including after an exception. Existing executor initialization, argument forwarding and Future behavior are preserved. No dependency or public API changes.

🧪 Testing

• Real-thread regression/control tests: request trace ID and parent span, queued submission snapshots, isolation after both success and failure, and initializer/task argument compatibility. No mocks, backend or LLM are used in the new cases.
• Unchanged main: 4 regression failures and 1 control pass, reproduced with both OpenTelemetry 1.45.1 and the lockfile's 1.31.1 SDK.
• Fixed branch: python -m pytest tests/unit/sdk -q — 155 passed, including the new five cases (Python 3.12.14, OpenTelemetry 1.31.1, pytest 8.4.1).
• pre-commit run --all-files — Ruff lint and formatting pass (repository-pinned Ruff 0.12.9).
• git diff --cached --check — pass.

An initial broader run with pytest 9 / OpenTelemetry 1.45.1 hit exporter failures and a pytest-depends internal error. After aligning the SDK to the repository's locked OpenTelemetry version and using compatible pytest 8, the SDK suite above passed. This is not a claim that the full repository or live-provider integration tests passed.

Prepared with AI assistance; the reproductions and checks reported here were executed locally.