mirror of
https://github.com/hwchase17/langchain.git
synced 2026-05-17 13:00:49 +00:00
8b21400627
`langchain_core._api.deprecation` previously did `from
pydantic.v1.fields import FieldInfo as FieldInfoV1` at module scope,
which triggers Pydantic's `UserWarning("Core Pydantic V1 functionality
isn't compatible with Python 3.14 or greater.")` on every
`langchain_core` import under 3.14+. The v1 symbol is only needed inside
one runtime branch of `@deprecated`, so it's now resolved lazily.
## Changes
- Replace the top-level v1 `FieldInfo` import with
`_is_pydantic_v1_field_info`, which probes
`sys.modules.get("pydantic.v1.fields")` instead of forcing the import.
The reconstruction inside `deprecated`'s `finalize` closure imports
`FieldInfoV1` lazily, gated by the predicate — so the warning only fires
if a caller has already loaded `pydantic.v1` themselves.
- Add a subprocess-based regression test asserting that importing
`langchain_core._api.deprecation` does not pull any `pydantic.v1*`
module into `sys.modules`. Verified to fail when the eager import is
reintroduced.
- Add a v1 `FieldInfo` decoration test — the v1 branch of `@deprecated`
previously had zero direct coverage.
- Update the stale `# Last Any should be FieldInfoV1 but this leads to
circular imports` comment on `T`'s bound, which no longer reflects the
real reason (it's about the 3.14 warning, not circularity).