The Fix
Upgrade to version 2.0.0 or later.
Based on closed pallets/flask issue #3905 · 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%.
@@ -135,10 +135,7 @@ initialization functions:
Classes work mostly like initialization functions but can later be
- used to further change the behavior. For an example look at how the
- `OAuth extension`_ works: there is an `OAuth` object that provides
- some helper functions like `OAuth.remote_app` to create a reference to
Option A — Upgrade to fixed release\nUpgrade to version 2.0.0 or later.\nWhen NOT to use: This fix is not applicable if the documentation needs to reference other unmaintained projects.\n\n
Why This Fix Works in Production
- Trigger: Users may encounter outdated information leading to confusion when implementing OAuth.
- Mechanism: Flask-OAuth was referenced in documentation despite being unmaintained
- Why the fix works: Removed the mention of Flask-OAuth in the extension development documentation to address the issue of referencing an unmaintained project. (first fixed release: 2.0.0).
- 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
- Flask-OAuth was referenced in documentation despite being unmaintained
- Production symptom (often without a traceback): Users may encounter outdated information leading to confusion when implementing OAuth.
Proof / Evidence
- GitHub issue: #3905
- Fix PR: https://github.com/pallets/flask/pull/3916
- First fixed release: 2.0.0
- Reproduced locally: No (not executed)
- Last verified: 2026-02-09
- Confidence: 0.85
- Did this fix it?: Yes (upstream fix exists)
- Own content ratio: 0.72
Discussion
High-signal excerpts from the issue thread (symptoms, repros, edge-cases).
“authlib is also a good choice for oauth in flask”
“It's just used to demonstrate how to initialize the extension with classes for the extension developer, I don't think it needs to update.”
Failure Signature (Search String)
- Users may encounter outdated information leading to confusion when implementing OAuth.
Copy-friendly signature
Failure Signature
-----------------
Users may encounter outdated information leading to confusion when implementing OAuth.
Error Message
Signature-only (no traceback captured)
Error Message
-------------
Users may encounter outdated information leading to confusion when implementing OAuth.
What Broke
Users may encounter outdated information leading to confusion when implementing OAuth.
Why It Broke
Flask-OAuth was referenced in documentation despite being unmaintained
Fix Options (Details)
Option A — Upgrade to fixed release Safe default (recommended)
Upgrade to version 2.0.0 or later.
Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.
Fix reference: https://github.com/pallets/flask/pull/3916
First fixed release: 2.0.0
Last verified: 2026-02-09. Validate in your environment.
When NOT to Use This Fix
- This fix is not applicable if the documentation needs to reference other unmaintained projects.
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 |
|---|---|
| 2.0.0 | Fixed |
Related Issues
No related fixes found.
Sources
We don’t republish the full GitHub discussion text. Use the links above for context.