httpx auth doesn't seem to be used in Client.stream (Fix)

The Fix

Upgrade to version 0.15.2 or later.

Based on closed encode/httpx issue #1256 · 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%.

Jump to Verify Open PR/Commit

@@ -234,7 +234,7 @@ def stream(
         headers: HeaderTypes = None,
         cookies: CookieTypes = None,
-        auth: AuthTypes = None,
+        auth: typing.Union[AuthTypes, UnsetType] = UNSET,
         allow_redirects: bool = True,

repro.py

Python 3.7.7 (default, May 16 2020, 11:38:23) 
[GCC 10.1.1 20200507 (Red Hat 10.1.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>> import httpx
>> httpx.__version__
'0.14.3'
>>

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

fix.md

Option A — Upgrade to fixed release\nUpgrade to version 0.15.2 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: auth doesn't seem to be used in Client.stream
Mechanism: Fixes the issue where the Client.stream method did not use the authentication provided in the Client initializer.
Why the fix works: Fixes the issue where the Client.stream method did not use the authentication provided in the Client initializer. (first fixed release: 0.15.2).

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

Shows up under Python 3.7.7 in real deployments (not just unit tests).
Production symptom (often without a traceback): auth doesn't seem to be used in Client.stream

Proof / Evidence

GitHub issue: #1256
Fix PR: https://github.com/encode/httpx/pull/1312
First fixed release: 0.15.2
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.67

Discussion

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

Jump to Sources Open on GitHub

“Hmm — not able to reproduce… Does the above^ reproduce the issue on your side? If not, what is the host you're requesting exactly? Could…”

@florimondmanca · 2020-09-04 · source

“Hello @florimondmanca / @tomchristie, With version 0.15.0, I can reproduce the issue”

@enguerranchevalier · 2020-09-23 · source

Failure Signature (Search String)

auth doesn't seem to be used in Client.stream
resp.raise_for_status() # no error is raised

Copy-friendly signature

signature.txt

Failure Signature
-----------------
auth doesn't seem to be used in Client.stream
resp.raise_for_status()  # no error is raised

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
auth doesn't seem to be used in Client.stream
resp.raise_for_status()  # no error is raised

Minimal Reproduction

repro.py

Python 3.7.7 (default, May 16 2020, 11:38:23) 
[GCC 10.1.1 20200507 (Red Hat 10.1.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>> import httpx
>> httpx.__version__
'0.14.3'
>>

Environment

Python: 3.7.7

Fix Options (Details)

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

Upgrade to version 0.15.2 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/httpx/pull/1312

First fixed release: 0.15.2

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.

Verify Fix

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

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.
Add a TLS smoke test that performs a real handshake in CI (include CA bundle validation and hostname checks).
Alert on handshake failures by error string and endpoint to catch cert/CA changes quickly.

Version Compatibility Table

Version	Status
0.15.2	Fixed

Related Issues

No related fixes found.

Cluster: httpx:configuration-error All hubs All clusters

Related clusters: Data consistency Other Timeout

Sources

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