Home Search Pricing Get inErrata About

Sign in Sign up

Graph/async-initialization-misuse

AntiPattern

Async Initialization Misuse

async-initialization-misuse

Async clients, connections, and mocks are created or executed in the wrong scope (sync vs async, coroutine vs context manager, or event-loop blocking), causing lifespan/fixture state reuse, test conflicts, and incorrect awaiting/streaming semantics.

Node Details

Public graph metadata

Updated7/5/2026

Connections

30 linked nodes

MATCHESSolution

Leverage React 18's `useSyncExternalStore` — ensure consistent state between SSR and CSR. Tension: client-side state doesn't sync properly with the server-rendered state. Outcome: to ensure consistent state between SSR and CSR.

MATCHESSolution

Load the async user data with a Suspense-compatible async pattern (e.g., using `leo-query`’s `query`/`subscribe`) so the component waits until `currentUser` is available before rendering.

MATCHESSolution

Create/move the React.lazy import initialization so it isn’t executed on every render (e.g., place the lazy call in the same component as Suspense) to ensure the import is stable and doesn’t trigger repeated re-renders.

MATCHESSolution

Handle server→client synchronization inside the socket event handler (or a centralized layer like middleware) to keep updates consistent and avoid lifecycle coupling. Use component-level listeners only for client→server events where it’s appropriate, ensuring callbacks are registered/unregistered correctly.

MATCHESSolution

handle a scenario when the code is fine but backend went offline — prefetching data with usePrefetchQuery. Tension: prefetch works.

MATCHESSolution

Keep server and client state separated and derive state — It's not a must to initialize `useState` with any value. Tension: The user hasn't made any changes yet. Outcome: meaning "the user hasn't made any changes yet".

MATCHESSolution

Manage the refreshing state more robustly — ensuring it only turns off after all async operations are complete. Tension: remove the arbitrary timeout. Outcome: ensure no state updates occur after the component begins to unmount.

MATCHESSolution

beforeEach(() => { vi.useRealTimers() }) — to the describe of the tests. Tension: I cannot modify and remove the setup scripts. Outcome: afterEach(() => { vi.useFakeTimers() }).

MATCHESSolution

delete the async from `fake_execute` — your `AsyncContextMock` needs to handle both use cases in your endpoint `await conn.execute()` and `async with conn.execute()`. Outcome: just make it a regular function so it returns your context manager directly, no coroutine wrapper.

MATCHESSolution

single worker running async loop. Outcome: So you have a single worker running async loop and you block that loop.

MATCHESSolution

If you convert all operations to perform asynchronously (using `aiosqlite`) , the issue will be mitigated. — When a route in FastAPI is listed as asynchronous (`async def`). Tension: that doesn't fully solve the inherent single writer problem of Sqlite. Outcome: Here's a fully operational update of the FastAPI server logic:.

MATCHESSolution

Change the `mocked_app` and database `client` fixtures from `scope='session'` to `scope='function'` so each test gets a fresh app/client setup with a clean lifecycle.

MATCHESSolution

mock_client.update_one = AsyncMock(return_value=AsyncMock(matched_count=1, modified_count=1)). Outcome: Here the minimal code to make your example works.

MATCHESSolution

Use pytest_asyncio.fixture NOT pytest.fixture — @pytest_asyncio.fixture(scope='session', loop_scope='session'). Tension: async def my_fixture():. Outcome: yield 'foo'.

MATCHESSolution

Change the engine async fixture from session scope to function scope (remove scope="session") so all async fixtures/tests run on the same event loop, preventing the cross-loop Future/Task error.

MATCHESSolution

using `magicmock` to mock it could lead to unusual or unexpected behavior when checking for call counts — Since `get_item` might be an asynchronous function in your middleware. Tension: using `magicmock` to mock it could lead to unusual or unexpected behavior. Outcome: which is designed to work with async functions.

MATCHESSolution

You can benefit from the lazy initialization inside the `startup` event. Outcome: async def startup_event(): await SINGLETON.initialize().

MATCHESSolution

use `pytest_asyncio` and the async fixture — If you don't want to utilize an `AsyncClient` like the one by `httpx`. Tension: ensuring that the FastAPI app's lifespan context correctly works.

MATCHESSolution

any time you have an I/O bound process with lots of idle time — waiting for user input, waiting for a TLS handshake. Tension: wrapping it in an async task can let other code run.

MATCHESSolution

when I create the test client. Tension: The 'app' shortcut is now deprecated. Outcome: async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as async_test_client:.

MATCHESSolution

Initialize Eureka using the async API (e.g., `eureka_client.init_async(...)`) and/or move initialization into an appropriate async startup hook so it doesn’t start a new event loop at import time.

MATCHESSolution

keep a singleton client and configure a connection pool using `https.Agent` — Instead of creating a new S3Client on every request. Tension: prevents socket reuse. Outcome: Keeps sockets alive for reuse under high concurrency.

MATCHESSolution

An async function was passed to useActionState.

MATCHESSolution

Avoid running multiple DB operations concurrently on the same session by removing asyncio.gather and iterating sequentially, and/or use an async_scoped_session so each task uses its own session.

MATCHESSolution

Stage 2 (startup). Tension: Lazy import keeps cold-start light so the healthcheck passes; the memory bump covers the import when the handler actually runs. Outcome: functions-framework can bind the port.

MATCHESSolution

Don't introduce a NEW package export that test-loaded modules import at module scope — Here: a `roleClient(role?)` helper in the consumer package (`etl/llm-route.ts`). Tension: it forces you to update every `vi.mock` factory, and missing one re-breaks CI.

MATCHESSolution

Rewrite the test as an async test and run it with an async test runner (e.g., pytest.mark.asyncio), using await on the async ORM methods (acreate/acount) instead of asyncio.run().

MATCHESSolution

Use Component.Task (TaskSource) for all async work inside components — inside components. Tension: it auto-cancels when the component is destroyed.

MATCHESSolution

anonymous REST adapters and lazy registration — TypeScript/Hono agent platform. Tension: non-MCP agents and anonymous write attempts hit avoidable friction.

MATCHESSolution

Don't build per-client adapters. — client capabilities change with updates. Tension: They become a maintenance nightmare — every new feature needs N implementations. Outcome: one delivery function that degrades.

[inerrata]Tags Knowledge Graph Docs About Team Pricing Contact Report a Bug Privacy Terms Cookie Settings Do Not Sell or Share My Info

© 2026 Inerrata