Pydantic Field deprecation with typing

The Fix

pip install pydantic==1.10.16

Based on closed pydantic/pydantic issue #9575 · 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

@@ -723,17 +723,27 @@ print(Model.model_json_schema()['properties']['deprecated_field'])
 ### `deprecated` via the `warnings.deprecated` decorator
 
+!!! note
+    You can only use the `deprecated` decorator in this way if you have
+    `typing_extensions` >= 4.9.0 installed.

repro.py

from typing_extensions import Annotated, deprecated

from pydantic import BaseModel, Field


class Model(BaseModel):
    deprecated_field: Annotated[int, deprecated('This is deprecated')]

    # Or explicitly using `Field`:
    alt_form: Annotated[int, Field(deprecated=deprecated('This is deprecated'))]

print(Model.model_json_schema()['properties']['deprecated_field'])

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\npip install pydantic==1.10.16\nWhen NOT to use: This fix is not applicable if using a version of typing_extensions lower than 4.9.\n\n

Why This Fix Works in Production

Trigger: pydantic version: v2.7.2, pydantic-core version: v2.18.3
Mechanism: The deprecation decorator was not functioning correctly due to a version mismatch with typing_extensions
Why the fix works: Updated the documentation to clarify the usage of the `deprecated` decorator with a version requirement for `typing_extensions`. (first fixed release: 1.10.16).

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 3.11 in real deployments (not just unit tests).
The deprecation decorator was not functioning correctly due to a version mismatch with typing_extensions
Surfaces as: pydantic version: v2.7.2, pydantic-core version: v2.18.3

Proof / Evidence

GitHub issue: #9575
Fix PR: https://github.com/pydantic/pydantic/pull/9578
First fixed release: 1.10.16
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.45

Discussion

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

Jump to Sources Open on GitHub

“> besides, no warnings are raised whatsoever when I created the model, when I instantiated it, when I access or modified to deprecated field”

@MarcBresson · 2024-06-05 · source

“@MarcBresson, I think you need typing_extensions >= 4.9 for this to work, I'll work on a fix for the docs.”

@sydney-runkle · 2024-06-05 · source

Failure Signature (Search String)

pydantic version: v2.7.2, pydantic-core version: v2.18.3

Error Message

Stack trace

error.txt

Error Message
-------------
pydantic version: v2.7.2, pydantic-core version: v2.18.3
Traceback (most recent call last):
  File "", line 6, in 
  File "/lib/python3.11/site-packages/pydantic/_internal/_model_construction.py", line 215, in __new__
    set_deprecated_descriptors(cls)
  File "/lib/python3.11/site-packages/pydantic/_internal/_model_construction.py", line 580, in set_deprecated_descriptors
    if (msg := field_info.deprecation_message) is not None:
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python3.11/site-packages/pydantic/fields.py", line 530, in deprecation_message
    return self.deprecated if isinstance(self.deprecated, str) else self.deprecated.message
                                                                    ^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'function' object has no attribute 'message'

Minimal Reproduction

repro.py

from typing_extensions import Annotated, deprecated

from pydantic import BaseModel, Field


class Model(BaseModel):
    deprecated_field: Annotated[int, deprecated('This is deprecated')]

    # Or explicitly using `Field`:
    alt_form: Annotated[int, Field(deprecated=deprecated('This is deprecated'))]

print(Model.model_json_schema()['properties']['deprecated_field'])

Environment

Python: 3.11
Pydantic: 2

What Broke

Users encountered AttributeError when using deprecated fields in Pydantic models.

Why It Broke

The deprecation decorator was not functioning correctly due to a version mismatch with typing_extensions

Fix Options (Details)

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

pip install pydantic==1.10.16

When NOT to use: This fix is not applicable if using a version of typing_extensions lower than 4.9.

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/9578

First fixed release: 1.10.16

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

When NOT to Use This Fix

This fix is not applicable if using a version of typing_extensions lower than 4.9.

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.

Version Compatibility Table

Version	Status
1.10.16	Fixed

Related Issues

No related fixes found.

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Related clusters: Data consistency OpenAPI schema Serialization

Sources

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

Pydantic Field deprecation with typing_extension.deprecated example in `doc>concepts/fields` does (Fix)