uvicorn reloader does not watching sys.path (Fix)

The Fix

Upgrade to version 0.11.4 or later.

Based on closed Kludex/uvicorn issue #582 · 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

@@ -178,7 +178,7 @@ def __init__(
 
         if reload_dirs is None:
-            self.reload_dirs = sys.path
+            self.reload_dirs = [os.getcwd()]
         else:

fix.md

Option A — Upgrade to fixed release\nUpgrade to version 0.11.4 or later.\nWhen NOT to use: Do not use if it changes public behavior or if the failure cannot be reproduced.\n\n

Why This Fix Works in Production

Trigger: reloader does not watching sys.path
Mechanism: --reload-dir now defaults to CWD, instead of sys.path to reduce memory usage.
Why the fix works: --reload-dir now defaults to CWD, instead of sys.path to reduce memory usage. (first fixed release: 0.11.4).

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): reloader does not watching sys.path

Proof / Evidence

GitHub issue: #582
Fix PR: https://github.com/encode/uvicorn/pull/479
First fixed release: 0.11.4
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.75
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.62

Discussion

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

Jump to Sources Open on GitHub

“This is a documentation oversight — https://github.com/encode/uvicorn/pull/479 changed the behavior to watch os.get_cwd() to reduce high memory usage (https://github.com/encode/uvicorn/pull/452).”

@florimondmanca · 2020-04-02 · source

Failure Signature (Search String)

reloader does not watching sys.path
`--reload-dir <path>` - Specify which directories to watch for python file changes. May be used multiple times. If unused, then by default all directories in `sys.path` will be

Copy-friendly signature

signature.txt

Failure Signature
-----------------
reloader does not watching sys.path
`--reload-dir <path>` - Specify which directories to watch for python file changes. May be used multiple times. If unused, then by default all directories in `sys.path` will be watched.

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
reloader does not watching sys.path
`--reload-dir <path>` - Specify which directories to watch for python file changes. May be used multiple times. If unused, then by default all directories in `sys.path` will be watched.

Fix Options (Details)

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

Upgrade to version 0.11.4 or later.

When NOT to use: Do not use if it changes public behavior or if the failure cannot be reproduced.

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

Fix reference: https://github.com/encode/uvicorn/pull/479

First fixed release: 0.11.4

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

When NOT to Use This Fix

Do not use if it changes public behavior or if the failure cannot be reproduced.

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
0.11.4	Fixed

Related Issues

No related fixes found.

Cluster: uvicorn:configuration-error All hubs All clusters

Related clusters: Data consistency Race condition SSL handshake

Sources

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