The Fix
pip install urllib3==1.25
Based on closed urllib3/urllib3 issue #1400 · 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%.
@@ -10,4 +10,4 @@ psutil==4.3.1
pytest-timeout==1.2.0
pytest==3.1.0
-gcp-devrel-py-tools==0.0.7
+gcp-devrel-py-tools==0.0.15; python_version>"2.6"
diff --git a/test/appengine/conftest.py b/test/appengine/conftest.py
Option A — Upgrade to fixed release\npip install urllib3==1.25\nWhen NOT to use: This fix should not be applied if using a Python version below 2.6.\n\n
Why This Fix Works in Production
- Trigger: Saw this in a different PR with unrelated changes: https://travis-ci.org/urllib3/urllib3/jobs/393557123#L552
- Mechanism: The version of gcp-devrel-py-tools was outdated, causing CI failures in Google App Engine tests
- Why the fix works: Updated the version of gcp-devrel-py-tools to fix App Engine builds, addressing issue #1400. (first fixed release: 1.25).
- 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
- The version of gcp-devrel-py-tools was outdated, causing CI failures in Google App Engine tests
- Production symptom (often without a traceback): Saw this in a different PR with unrelated changes: https://travis-ci.org/urllib3/urllib3/jobs/393557123#L552
Proof / Evidence
- GitHub issue: #1400
- Fix PR: https://github.com/urllib3/urllib3/pull/1407
- First fixed release: 1.25
- Reproduced locally: No (not executed)
- Last verified: 2026-02-09
- Confidence: 0.95
- 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).
“Saw this in a different PR with unrelated changes: https://travis-ci.org/urllib3/urllib3/jobs/393557123#L552 Has GAE testbed changed, maybe we need to update our scripts. Assigning this to you Thea as our GAE champion.”
Failure Signature (Search String)
- Saw this in a different PR with unrelated changes: https://travis-ci.org/urllib3/urllib3/jobs/393557123#L552
- Has GAE testbed changed, maybe we need to update our scripts.
Copy-friendly signature
Failure Signature
-----------------
Saw this in a different PR with unrelated changes: https://travis-ci.org/urllib3/urllib3/jobs/393557123#L552
Has GAE testbed changed, maybe we need to update our scripts.
Error Message
Signature-only (no traceback captured)
Error Message
-------------
Saw this in a different PR with unrelated changes: https://travis-ci.org/urllib3/urllib3/jobs/393557123#L552
Has GAE testbed changed, maybe we need to update our scripts.
What Broke
CI builds for Google App Engine were failing, preventing successful integration.
Why It Broke
The version of gcp-devrel-py-tools was outdated, causing CI failures in Google App Engine tests
Fix Options (Details)
Option A — Upgrade to fixed release Safe default (recommended)
pip install urllib3==1.25
Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.
Fix reference: https://github.com/urllib3/urllib3/pull/1407
First fixed release: 1.25
Last verified: 2026-02-09. Validate in your environment.
When NOT to Use This Fix
- This fix should not be applied if using a Python version below 2.6.
Did This Fix Work in Your Case?
Quick signal helps us prioritize which fixes to verify and improve.
Prevention
- Add a CI check that diffs key outputs after upgrades (OpenAPI schema snapshots, JSON payload shapes, CLI output).
- Upgrade behind a canary and run integration tests against the canary before 100% rollout.
Version Compatibility Table
| Version | Status |
|---|---|
| 1.25 | Fixed |
Related Issues
No related fixes found.
Sources
We don’t republish the full GitHub discussion text. Use the links above for context.