Pydantic unhashable type: 'AliasPath' raised from

The Fix

pip install pydantic==2.7.1

Based on closed pydantic/pydantic issue #9239 · 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

@@ -2,7 +2,9 @@
 
 import dataclasses
-from typing import Callable, Literal
+from typing import Any, Callable, Literal
+

repro.py

#!/usr/bin/env python3
from pydantic import AliasPath, BaseModel, Field

class Example(BaseModel):
    value: str = Field(validation_alias=AliasPath("data", "value"))


if __name__ == "__main__":
    example = Example.model_construct(value="value")
    assert example.value == "value"

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==2.7.1\nWhen NOT to use: Do not use this fix if your code relies on the previous behavior of validation aliases.\n\n

Why This Fix Works in Production

Trigger: example = Example.model_construct(value="value")
Mechanism: The error occurs due to unhandled validation aliases for AliasPath in model_construct
Why the fix works: Fixes the unhashable type error raised from BaseModel.model_construct() by properly handling validation aliases for AliasPath and AliasChoices. (first fixed release: 2.7.1).

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 3.12 in real deployments (not just unit tests).
The error occurs due to unhandled validation aliases for AliasPath in model_construct
Surfaces as: Traceback (most recent call last):

Proof / Evidence

GitHub issue: #9239
Fix PR: https://github.com/pydantic/pydantic/pull/9223
First fixed release: 2.7.1
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.56

Verified Execution

We executed the runnable minimal repro in a temporary environment and captured exit codes + logs.

Status: PASS
Ran: 2026-02-11T16:52:29Z
Package: pydantic
Fixed: 2.7.1
Mode: fixed_only
Outcome: ok

Logs

affected (exit=None)

fixed (exit=0)

Discussion

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

Jump to Sources Open on GitHub

“Hi @jessemyers-lettuce, This is fixed on main by https://github.com/pydantic/pydantic/pull/9223. We'll do a patch release with this fix early next week!”

@sydney-runkle · 2024-04-13 · confirmation · source

Failure Signature (Search String)

example = Example.model_construct(value="value")

Error Message

Stack trace

error.txt

Error Message
-------------
Traceback (most recent call last):
  File "/path/to/main.py", line 9, in <module>
    example = Example.model_construct(value="value")
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/path/to/venv/lib/python3.12/site-packages/pydantic/main.py", line 228, in model_construct
    elif field.validation_alias is not None and field.validation_alias in values:
                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: unhashable type: 'AliasPath'

Minimal Reproduction

repro.py

#!/usr/bin/env python3
from pydantic import AliasPath, BaseModel, Field

class Example(BaseModel):
    value: str = Field(validation_alias=AliasPath("data", "value"))


if __name__ == "__main__":
    example = Example.model_construct(value="value")
    assert example.value == "value"

Environment

Python: 3.12
Pydantic: 2

What Broke

Users experience TypeError when constructing models with validation aliases.

Why It Broke

The error occurs due to unhandled validation aliases for AliasPath in model_construct

Fix Options (Details)

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

pip install pydantic==2.7.1

When NOT to use: Do not use this fix if your code relies on the previous behavior of validation aliases.

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/9223

First fixed release: 2.7.1

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

When NOT to Use This Fix

Do not use this fix if your code relies on the previous behavior of validation aliases.

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
2.7.1	Fixed

Related Issues

No related fixes found.

Cluster: pydantic:configuration-error Pydantic hub Pydantic best practices All hubs All clusters

Related clusters: Data consistency OpenAPI schema Serialization

Sources

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

Pydantic unhashable type: 'AliasPath' raised from BaseModel.model_construct() (Fix)