Pydantic Make `ComputedFieldInfo` class non-public (Fix)

The Fix

pip install pydantic==2.6.4

Based on closed pydantic/pydantic issue #8902 · PR/commit linked

Open PR/Commit

@@ -30,6 +30,8 @@
     DeprecationWarning = PydanticDeprecatedSince20
 
+__all__ = 'Field', 'PrivateAttr', 'computed_field'
+

fix.md

Option A — Upgrade to fixed release\npip install pydantic==2.6.4\nWhen NOT to use: This fix is not applicable if the public API needs to remain unchanged.\n\n

Why This Fix Works in Production

Trigger: https://github.com/pydantic/pydantic/pull/8237#discussion_r1503542165
Mechanism: The `ComputedFieldInfo` class was made public, exposing internal utilities
Why the fix works: Adds `__all__` to `fields.py` and makes some utilities not explicitly public, addressing issue #8902. (first fixed release: 2.6.4).

Why This Breaks in Prod

The `ComputedFieldInfo` class was made public, exposing internal utilities
Production symptom (often without a traceback): https://github.com/pydantic/pydantic/pull/8237#discussion_r1503542165

Proof / Evidence

GitHub issue: #8902
Fix PR: https://github.com/pydantic/pydantic/pull/8925
First fixed release: 2.6.4
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.75
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.83

Discussion

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

Jump to Sources Open on GitHub

“https://github.com/pydantic/pydantic/pull/8237#discussion_r1503542165”

Issue thread · issue description · source

Failure Signature (Search String)

https://github.com/pydantic/pydantic/pull/8237#discussion_r1503542165

Copy-friendly signature

signature.txt

Failure Signature
-----------------
https://github.com/pydantic/pydantic/pull/8237#discussion_r1503542165

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
https://github.com/pydantic/pydantic/pull/8237#discussion_r1503542165

What Broke

Internal utilities were unintentionally exposed, leading to potential misuse.

Why It Broke

The `ComputedFieldInfo` class was made public, exposing internal utilities

Fix Options (Details)

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

pip install pydantic==2.6.4

When NOT to use: This fix is not applicable if the public API needs to remain unchanged.

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

Fix reference: https://github.com/pydantic/pydantic/pull/8925

First fixed release: 2.6.4

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

When NOT to Use This Fix

This fix is not applicable if the public API needs to remain unchanged.

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
2.6.4	Fixed

Related Issues

No related fixes found.

Cluster: pydantic:other Pydantic hub Pydantic best practices All hubs All clusters

Related clusters: Configuration error Data consistency OpenAPI schema

Sources

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