starlette mypy errors when accessing Request.state (Fix)

The Fix

Upgrade to version 0.13.4 or later.

Based on closed Kludex/starlette issue #545 · PR/commit linked

Production note: Most teams hit this during upgrades or environment changes. Roll out with a canary and smoke critical endpoints (health, OpenAPI/docs) before 100%.

Open PR/Commit

@@ -29,7 +29,7 @@ async def call_next(self, request: Request) -> Response:
         queue = asyncio.Queue()  # type: asyncio.Queue
 
-        scope = dict(request)
+        scope = request.scope
         receive = request.receive

fix.md

Option A — Upgrade to fixed release\nUpgrade to version 0.13.4 or later.\nWhen NOT to use: This fix is not suitable if strict type checking is required for all attributes.\n\n

Why This Fix Works in Production

Trigger: mypy errors when accessing Request.state
Mechanism: Addresses mypy errors when accessing Request.state by implementing a State class with dynamic attribute handling.
Why the fix works: Addresses mypy errors when accessing Request.state by implementing a State class with dynamic attribute handling. (first fixed release: 0.13.4).

Production impact:

If left unfixed, the same config can fail only in production (env differences), causing startup failures or partial feature outages.

Why This Breaks in Prod

Production symptom (often without a traceback): mypy errors when accessing Request.state

Proof / Evidence

GitHub issue: #545
Fix PR: https://github.com/kludex/starlette/pull/557
First fixed release: 0.13.4
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.65

Discussion

High-signal excerpts from the issue thread (symptoms, repros, edge-cases).

Jump to Sources Open on GitHub

“I guess we could explicitly add __getattr__, __setattr__, and __delattr__ methods, just to signal that it really is just an untyped container object”

@lovelydinosaur · 2019-06-14 · source

Failure Signature (Search String)

mypy errors when accessing Request.state
This causes mypy errors since any accessed/set attributes aren't present in the `State` class. As far as I can tell, there isn't a good way to tell mypy to expect certain

Copy-friendly signature

signature.txt

Failure Signature
-----------------
mypy errors when accessing Request.state
This causes mypy errors since any accessed/set attributes aren't present in the `State` class. As far as I can tell, there isn't a good way to tell mypy to expect certain attributes to potentially be set.

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
mypy errors when accessing Request.state
This causes mypy errors since any accessed/set attributes aren't present in the `State` class. As far as I can tell, there isn't a good way to tell mypy to expect certain attributes to potentially be set.

Fix Options (Details)

Option A — Upgrade to fixed release Safe default (recommended)

Upgrade to version 0.13.4 or later.

When NOT to use: This fix is not suitable if strict type checking is required for all attributes.

Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.

Option D — Guard side-effects with OnceOnly Guardrail for side-effects

Mitigate duplicate external side-effects under retries/timeouts/agent loops by gating the operation before calling external systems.

Place OnceOnly between your code/agent and real side-effects (Stripe, emails, CRM, APIs).
Use a stable key per side-effect (e.g., customer_id + action + idempotency_key).
Fail-safe: configure fail-open vs fail-closed based on blast radius and spend risk.

Show example snippet (optional)

onceonly.py

from onceonly import OnceOnly
import os

once = OnceOnly(api_key=os.environ["ONCEONLY_API_KEY"], fail_open=True)

# Stable idempotency key per real side-effect.
# Use a request id / job id / webhook delivery id / Stripe event id, etc.
event_id = "evt_..."  # replace
key = f"stripe:webhook:{event_id}"

res = once.check_lock(key=key, ttl=3600)
if res.duplicate:
    return {"status": "already_processed"}

# Safe to execute the side-effect exactly once.
handle_event(event_id)

See OnceOnly SDK

When NOT to use: Do not use this to hide logic bugs or data corruption. Use it to block duplicate external side-effects and enforce tool permissions/spend caps.

Fix reference: https://github.com/kludex/starlette/pull/557

First fixed release: 0.13.4

Last verified: 2026-02-09. Validate in your environment.

When NOT to Use This Fix

This fix is not suitable if strict type checking is required for all attributes.
Do not use this to hide logic bugs or data corruption. Use it to block duplicate external side-effects and enforce tool permissions/spend caps.

Did This Fix Work in Your Case?

Quick signal helps us prioritize which fixes to verify and improve.

Prevention

Capture the exact failing error string in logs and tests so you can reproduce via a minimal script.
Pin production dependencies and upgrade only with a reproducible test that hits the failing path.

Version Compatibility Table

Version	Status
0.13.4	Fixed

Related Issues

No related fixes found.

Cluster: starlette:configuration-error All hubs All clusters

Related clusters: Data consistency SSL handshake Other

Sources

We don’t republish the full GitHub discussion text. Use the links above for context.