starlette fix Unraisable ResourceWarnings (Fix)

The Fix

Upgrade to version 0.14.2 or later.

Based on closed Kludex/starlette issue #1050 · PR/commit linked

Open PR/Commit

@@ -217,15 +217,15 @@ def generate_html(self, exc: Exception, limit: int = 7) -> str:
             exc, capture_locals=True
         )
-        frames = inspect.getinnerframes(
-            traceback_obj.exc_traceback, limit  # type: ignore
-        )

fix.md

Option A — Upgrade to fixed release\nUpgrade to version 0.14.2 or later.\nWhen NOT to use: Do not apply this fix if the context management behavior of sockets is intentionally modified.\n\n

Why This Fix Works in Production

Trigger: ResourceWarnings are raised during the execution of the TestClient due to unclosed sockets.
Mechanism: Various objects are not used in context managers, leading to unclosed sockets and ResourceWarnings
Why the fix works: Fixes ResourceWarnings in TestClient by ensuring that sockets are properly closed. (first fixed release: 0.14.2).

Why This Breaks in Prod

Various objects are not used in context managers, leading to unclosed sockets and ResourceWarnings
Production symptom (often without a traceback): ResourceWarnings are raised during the execution of the TestClient due to unclosed sockets.

Proof / Evidence

GitHub issue: #1050
Fix PR: https://github.com/kludex/starlette/pull/1132
First fixed release: 0.14.2
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.75
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.77

Discussion

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

Jump to Sources Open on GitHub

“it looks like various objects are not used in context managers, or pass on the __exit__ to their super class”

@graingert · 2020-09-07 · source

Failure Signature (Search String)

ResourceWarnings are raised during the execution of the TestClient due to unclosed sockets.

Copy-friendly signature

signature.txt

Failure Signature
-----------------
ResourceWarnings are raised during the execution of the TestClient due to unclosed sockets.

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
ResourceWarnings are raised during the execution of the TestClient due to unclosed sockets.

What Broke

ResourceWarnings are raised during the execution of the TestClient due to unclosed sockets.

Why It Broke

Various objects are not used in context managers, leading to unclosed sockets and ResourceWarnings

Fix Options (Details)

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

Upgrade to version 0.14.2 or later.

When NOT to use: Do not apply this fix if the context management behavior of sockets is intentionally modified.

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

Fix reference: https://github.com/kludex/starlette/pull/1132

First fixed release: 0.14.2

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

When NOT to Use This Fix

Do not apply this fix if the context management behavior of sockets is intentionally modified.

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
0.14.2	Fixed

Related Issues

No related fixes found.

Cluster: starlette:other All hubs All clusters

Related clusters: Configuration error Data consistency SSL handshake

Sources

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