docs: document the Litestar, Flask and Celery integration fixes

docs/integrations/celery.md

@@ -63,7 +63,7 @@ def run_report(report: typing.Annotated[Report, FromDI(Report)]) -> str:
     return report.render()
 ```
 
-`setup_di(app, container)` stores the container on `app.conf` and connects Celery's
+`setup_di(app, container)` registers the container for the app and connects Celery's
 worker signals that open and close it. `@inject` builds a `Scope.REQUEST` child container
 for each task call and resolves `FromDI`-annotated parameters from it. It looks the
 container up through Celery's `current_app` at call time, so it resolves against
@@ -105,12 +105,14 @@ Under prefork each child process gets its own APP-scoped instances. `worker_init
 container and closing one with nothing cached are both no-ops, so the overlap is
 harmless.
 
-!!! warning "The prefork pool fails on macOS"
-    On macOS, billiard starts prefork children with the spawn method, which pickles
-    the Celery app. The container that `setup_di` stores on `app.conf` cannot be
-    pickled, so the worker stops at startup with
-    `TypeError: cannot pickle '_thread._local' object`. Run the worker with
-    `--pool=solo` or `--pool=threads` there.
+!!! note "Prefork with the spawn start method"
+    Celery starts prefork children with fork on Linux and macOS. Spawn is used on Windows or
+    when you force it with `billiard.set_start_method("spawn", force=True)`, and Celery then
+    needs `FORKED_BY_MULTIPROCESSING=1` in the environment. Since modern-di-celery 4.0.1, a
+    spawn child gets the container that `setup_di` builds when the child re-imports your task
+    module, matched to the app by its `main` name, so give each app in a process its own name.
+    Earlier releases store the container on `app.conf`, which cannot be pickled, and the pool
+    fails at startup under spawn.
 
 Code that calls tasks without a worker, such as a script or a test in eager mode,
 fires none of these signals. Close the root yourself when it is done, for example
@@ -177,7 +179,7 @@ with container:
 
 | Symbol | Description |
 |---|---|
-| `setup_di(app, container)` | Wire the APP-scope container into Celery: stores it on `app.conf` and opens/closes it on `worker_process_init`/`worker_process_shutdown` and `worker_init`/`worker_shutdown`. Returns the container. |
+| `setup_di(app, container)` | Wire the APP-scope container into Celery: registers it for the app and opens/closes it on `worker_process_init`/`worker_process_shutdown` and `worker_init`/`worker_shutdown`. Returns the container. |
 | `FromDI(provider_or_type)` | Marker for `Annotated[T, FromDI(...)]` in task signatures; accepts a provider instance or a plain type. |
 | `@inject` | Decorator that builds a `Scope.REQUEST` child container per call, resolves `FromDI`-annotated parameters from it, and closes the child container with `close_sync()` afterwards. Raises `RuntimeError` naming `setup_di` when a task reaches it without `setup_di` called. A task with `FromDI` parameters that also declares `*args`/`**kwargs` raises `TypeError` at decoration. |
 | `DITask` | `Task` subclass that applies `@inject` to a task's `run` method automatically; pass `task_cls=DITask` to `Celery(...)` or `base=DITask` to `@app.task(...)`. |

docs/integrations/flask.md

@@ -3,9 +3,8 @@
 Flask has no dependency injection of its own, so `modern-di-flask` provides an `@inject` decorator
 that fills the view parameters marked with `FromDI`. `setup_di` installs a
 `before_request`/`teardown_appcontext` pair that gives each request a `Scope.REQUEST` child
-container and closes it with `close_sync()` once the request finishes. Resolution is sync-only,
-and views must be sync too: `@inject` on an `async def` view hands Flask a coroutine, and the
-request fails with `TypeError`.
+container and closes it with `close_sync()` once the request finishes. Views can be sync or
+`async def`, and resolution is sync for both.
 
 ## Installation
 
@@ -123,6 +122,33 @@ else:
     raise AssertionError("the late route was wrapped")
 -->
 
+### Async views
+
+Since modern-di-flask 4.1.0, `@inject` and `auto_inject=True` also take `async def` views. Flask
+runs them through asgiref, so install Flask's async extra (`flask[async]`). The markers are resolved
+from the request's child container before the view is awaited:
+
+```python
+async_app = Flask(__name__)
+
+
+@async_app.route("/async-report")
+@inject
+async def get_async_report(report: typing.Annotated[Report, FromDI(Report)]) -> dict[str, str]:
+    return report.as_dict()
+
+
+setup_di(async_app, Container(groups=[AppGroup]))
+```
+
+<!-- invisible-code-block: python
+async_app.testing = True
+assert async_app.test_client().get("/async-report").json == {"service": "catalog"}
+-->
+
+Teardown is still sync (`close_sync()`), so a REQUEST-scoped provider with an async finalizer is
+not supported; see [Scopes and lifecycle](#scopes-and-lifecycle).
+
 ## Scopes and lifecycle
 
 Flask has no websocket concept, so the integration only ever opens one child scope; see
@@ -136,8 +162,7 @@ and it or any other failing finalizer reaches Flask as a `FinalizerError` from t
 request then fails with a 500 under the Werkzeug server, and the test client raises the error.
 
 `setup_di` does not close the root container, because Flask has no application-shutdown hook to
-run it from. Close it yourself where your process shuts down, for example with `atexit`. That
-close is a `close_sync()` too, so APP-scoped finalizers must be sync as well:
+run it from. Close it yourself where your process shuts down, for example with `atexit`:
 
 ```python
 import atexit
@@ -147,6 +172,9 @@ from modern_di_flask import fetch_di_container
 atexit.register(fetch_di_container(app).close_sync)
 ```
 
+`close_sync()` cannot run an async finalizer. If an APP-scoped provider has one, close the root
+with `asyncio.run(fetch_di_container(app).close_async())` instead.
+
 ## Framework context objects
 
 The integration makes `flask.Request` available to your factories. See
@@ -207,6 +235,6 @@ assert request_app.test_client().get("/describe").json == [{"method": "GET", "ur
 |---|---|
 | `setup_di(app, container, *, auto_inject=False)` | Stores the container on `app.extensions`, registers the request context provider, installs the `before_request`/`teardown_appcontext` pair that builds and closes a per-request `Scope.REQUEST` child container, and, if `auto_inject=True`, wraps every currently registered view with `inject`; returns the container. It does not close the root container. |
 | `FromDI(dependency)` | Marker (used with `@inject`) that resolves a provider or type from the per-request child container. |
-| `inject` | Decorator for a sync view function; resolves its `FromDI`-annotated parameters. Raises `RuntimeError` naming `setup_di` when a request reaches it without `setup_di` called. |
+| `inject` | Decorator for a sync or `async def` view; returns a wrapper of the same kind and resolves its `FromDI`-annotated parameters. Raises `RuntimeError` naming `setup_di` when a request reaches it without `setup_di` called. |
 | `fetch_di_container(app)` | Returns the root `Container` stored on `app.extensions`. |
 | `flask_request_provider` | `ContextProvider` for `flask.Request` (REQUEST scope), auto-registered by type. |

docs/integrations/litestar.md

@@ -124,8 +124,10 @@ If an attribute name appears in more than one group, or matches a dependency the
 last one wins.
 
 !!! warning "Don't name a provider `di_container`"
-    An autowired provider named `di_container` replaces the plugin's own container dependency,
-    which every `FromDI` depends on. Litestar then fails to build the app with `RecursionError`.
+    The name `di_container` is reserved for the plugin's own dependency, which every `FromDI`
+    depends on. Since modern-di-litestar 4.0.1, an autowired group that declares a provider under
+    that name raises `litestar.exceptions.ImproperlyConfiguredException` when the app is created.
+    Earlier releases replace the plugin's dependency, and Litestar never finishes building the app.
 
 With `autowired_groups` set, `FromDI` on a route can still take a type. Pass a provider instance
 only for providers outside `autowired_groups`: Litestar rejects one provider registered under two

justfile

@@ -44,7 +44,7 @@ test-docs *args:
     uv run --no-sync pytest docs {{ args }}
 
 # Packages the docs import that no modern-di-<page> package depends on.
-docs_integration_extras := "faststream[kafka,nats] aiogram-dialog sqlalchemy[asyncio] asyncpg redis pydantic-ai-slim[openai]"
+docs_integration_extras := "faststream[kafka,nats] flask[async] aiogram-dialog sqlalchemy[asyncio] asyncpg redis pydantic-ai-slim[openai]"
 
 # Run every page under docs/, the framework pages under docs/integrations/ included, with the latest
 # modern-di-<page> release of every integration and the extras above installed and modern-di pinned to