HKUDS/DeepTutor · error · HTTPException

Mastery path changed activity while the operation was starti

Error message

Mastery path changed activity while the operation was starting; active session: {exc.lease.session_id}

What it means

Error "Mastery path changed activity while the operation was starting; active session: {exc.lease.session_id}" thrown in HKUDS/DeepTutor.

Source

Thrown at deeptutor/api/routers/mastery_path.py:127

@asynccontextmanager
async def _exclusive_path_mutation(book_id: str):
    """Cancel the tutor, then exclude a newly racing tutor/API write."""
    from deeptutor.learning.storage import PathLeaseConflictError

    await _cancel_active_learning_turn(book_id)
    store = LearningStore()
    operation_id = f"api-{uuid.uuid4().hex}"
    try:
        await asyncio.to_thread(
            store.acquire_path_lease,
            book_id,
            "__path_api__",
            operation_id,
            bind_session=False,
        )
    except PathLeaseConflictError as exc:
        raise HTTPException(
            status_code=409,
            detail=(
                "Mastery path changed activity while the operation was starting; "
                f"active session: {exc.lease.session_id}"
            ),
        ) from exc
    try:
        yield
    finally:
        await asyncio.to_thread(
            store.release_path_lease,
            book_id,
            turn_id=operation_id,
        )


# ── Request models ───────────────────────────────────────────────────────────

View on GitHub (pinned to 3e82f13042)

When it happens

Trigger: Thrown at deeptutor/api/routers/mastery_path.py:127 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of HKUDS/DeepTutor@3e82f13042 (2026-08-27). Data as JSON: /api/errors/f37f69630cdc5d92. Report an issue: GitHub.