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lancedb/python/python/tests/test_pydantic.py
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lancedb-gatefixer[bot] 85b0eba176 fix(python): support typed embedding vector fields (#3826)
## Summary

- infer fixed-size float32 Arrow vectors from `VectorField` metadata
when a model uses the standard `list[float]` annotation
- document the mypy-compatible embedding-field declaration while
preserving the existing `Vector(dim)` runtime API
- add regression coverage for schema conversion and model construction

## Root cause

`Vector(dim)` is a runtime constrained-type factory, but Python's static
typing rules do not permit call expressions in annotation positions.
Mypy's suggested `Vector[...]` spelling also cannot represent a
dimension computed at runtime and fails because `Vector` is a function.
`VectorField` already carries the embedding function and its dimension,
but schema conversion previously ignored that metadata for a statically
valid `list[float]` annotation.

The runtime factory remains available for dimension-constrained Pydantic
validation. Embedding-backed models that require mypy compatibility can
now use `list[float] = embedding.VectorField()`; LanceDB derives the
same nullable fixed-size float32 Arrow type from the field metadata.

## Validation

- `cd python && uv run --extra tests pytest
python/tests/test_pydantic.py -q` (23 passed)
- focused mypy check reproducing the original error and accepting the
new `LanceModel` declaration
- isolated schema checks with Pydantic 1.10.24 and 2.11.7
- `ruff format .`
- `ruff check .`

Fixes #1982

<!-- lance-gatekeeper-fix:v1 agent=877facbc659cdc9424bd367e12426366
generation=1 -->

Co-authored-by: Gatefixer <313497061+lancedb-gatefixer[bot]@users.noreply.github.com>
2026-09-29 12:00:52 -05:00

736 lines
20 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright The LanceDB Authors
import json
from datetime import date, datetime
from enum import Enum
from typing import List, Optional, Tuple
import pyarrow as pa
import pydantic
import pytest
from lancedb.conftest import MockTextEmbeddingFunction
from lancedb.pydantic import (
LanceModel,
MultiVector,
Vector,
pydantic_to_schema,
)
from pydantic import BaseModel
from pydantic import Field
def test_pydantic_to_arrow():
class StructModel(pydantic.BaseModel):
a: str
b: Optional[float]
class TestModel(pydantic.BaseModel):
id: int
s: str
vec: list[float]
li: list[int]
lili: list[list[float]]
litu: list[tuple[float, float]]
opt: Optional[str] = None
st: StructModel
dt: date
dtt: datetime
dt_with_tz: datetime = Field(json_schema_extra={"tz": "Asia/Shanghai"})
# d: dict
# TODO: test we can actually convert the model into data.
# m = TestModel(
# id=1,
# s="hello",
# vec=[1.0, 2.0, 3.0],
# li=[2, 3, 4],
# lili=[[2.5, 1.5], [3.5, 4.5], [5.5, 6.5]],
# litu=[(2.5, 1.5), (3.5, 4.5), (5.5, 6.5)],
# st=StructModel(a="a", b=1.0),
# dt=date.today(),
# dtt=datetime.now(),
# dt_with_tz=datetime.now(pytz.timezone("Asia/Shanghai")),
# )
schema = pydantic_to_schema(TestModel)
expect_schema = pa.schema(
[
pa.field("id", pa.int64(), False),
pa.field("s", pa.utf8(), False),
pa.field("vec", pa.list_(pa.float64()), False),
pa.field("li", pa.list_(pa.int64()), False),
pa.field("lili", pa.list_(pa.list_(pa.float64())), False),
pa.field("litu", pa.list_(pa.list_(pa.float64())), False),
pa.field("opt", pa.utf8(), True),
pa.field(
"st",
pa.struct(
[pa.field("a", pa.utf8(), False), pa.field("b", pa.float64(), True)]
),
False,
),
pa.field("dt", pa.date32(), False),
pa.field("dtt", pa.timestamp("us"), False),
pa.field("dt_with_tz", pa.timestamp("us", tz="Asia/Shanghai"), False),
]
)
assert schema == expect_schema
def test_optional_types_py310():
class TestModel(pydantic.BaseModel):
a: str | None
b: None | str
c: Optional[str]
schema = pydantic_to_schema(TestModel)
expect_schema = pa.schema(
[
pa.field("a", pa.utf8(), True),
pa.field("b", pa.utf8(), True),
pa.field("c", pa.utf8(), True),
]
)
assert schema == expect_schema
def test_optional_structs():
class SplitInfo(pydantic.BaseModel):
start_frame: int
end_frame: int
class TestModel(pydantic.BaseModel):
id: str
split: SplitInfo | None = None
schema = pydantic_to_schema(TestModel)
expect_schema = pa.schema(
[
pa.field("id", pa.utf8(), False),
pa.field(
"split",
pa.struct(
[
pa.field("start_frame", pa.int64(), False),
pa.field("end_frame", pa.int64(), False),
]
),
True,
),
]
)
assert schema == expect_schema
def test_optional_struct_list_py310():
class SplitInfo(pydantic.BaseModel):
start_frame: int
end_frame: int
class TestModel(pydantic.BaseModel):
id: str
splits: list[SplitInfo] | None = None
schema = pydantic_to_schema(TestModel)
expect_schema = pa.schema(
[
pa.field("id", pa.utf8(), False),
pa.field(
"splits",
pa.list_(
pa.struct(
[
pa.field("start_frame", pa.int64(), False),
pa.field("end_frame", pa.int64(), False),
]
)
),
True,
),
]
)
assert schema == expect_schema
def test_nested_struct_list():
class SplitInfo(pydantic.BaseModel):
start_frame: int
end_frame: int
class TestModel(pydantic.BaseModel):
id: str
splits: list[SplitInfo]
schema = pydantic_to_schema(TestModel)
expect_schema = pa.schema(
[
pa.field("id", pa.utf8(), False),
pa.field(
"splits",
pa.list_(
pa.struct(
[
pa.field("start_frame", pa.int64(), False),
pa.field("end_frame", pa.int64(), False),
]
)
),
False,
),
]
)
assert schema == expect_schema
def test_bare_generic_raises_type_error():
# A bare, unparameterised List/Tuple has no element type to map to Arrow.
# It should raise a clear TypeError, not crash with AttributeError: __args__.
for bare in (List, Tuple):
class TestModel(pydantic.BaseModel):
items: bare
with pytest.raises(TypeError, match="unsupported type"):
pydantic_to_schema(TestModel)
def test_nested_struct_list_optional():
class SplitInfo(pydantic.BaseModel):
start_frame: int
end_frame: int
class TestModel(pydantic.BaseModel):
id: str
splits: Optional[list[SplitInfo]] = None
schema = pydantic_to_schema(TestModel)
expect_schema = pa.schema(
[
pa.field("id", pa.utf8(), False),
pa.field(
"splits",
pa.list_(
pa.struct(
[
pa.field("start_frame", pa.int64(), False),
pa.field("end_frame", pa.int64(), False),
]
)
),
True,
),
]
)
assert schema == expect_schema
def test_nested_struct_list_optional_items():
class SplitInfo(pydantic.BaseModel):
start_frame: int
end_frame: int
class TestModel(pydantic.BaseModel):
id: str
splits: list[Optional[SplitInfo]]
schema = pydantic_to_schema(TestModel)
expect_schema = pa.schema(
[
pa.field("id", pa.utf8(), False),
pa.field(
"splits",
pa.list_(
pa.field(
"item",
pa.struct(
[
pa.field("start_frame", pa.int64(), False),
pa.field("end_frame", pa.int64(), False),
]
),
True,
)
),
False,
),
]
)
assert schema == expect_schema
def test_nested_struct_list_optional_container_and_items():
class SplitInfo(pydantic.BaseModel):
start_frame: int
end_frame: int
class TestModel(pydantic.BaseModel):
id: str
splits: Optional[list[Optional[SplitInfo]]] = None
schema = pydantic_to_schema(TestModel)
expect_schema = pa.schema(
[
pa.field("id", pa.utf8(), False),
pa.field(
"splits",
pa.list_(
pa.field(
"item",
pa.struct(
[
pa.field("start_frame", pa.int64(), False),
pa.field("end_frame", pa.int64(), False),
]
),
True,
)
),
True,
),
]
)
assert schema == expect_schema
def test_nested_struct_list_optional_items_pep604():
class SplitInfo(pydantic.BaseModel):
start_frame: int
end_frame: int
class TestModel(pydantic.BaseModel):
id: str
splits: list[SplitInfo | None]
schema = pydantic_to_schema(TestModel)
expect_schema = pa.schema(
[
pa.field("id", pa.utf8(), False),
pa.field(
"splits",
pa.list_(
pa.field(
"item",
pa.struct(
[
pa.field("start_frame", pa.int64(), False),
pa.field("end_frame", pa.int64(), False),
]
),
True,
)
),
False,
),
]
)
assert schema == expect_schema
def test_pydantic_to_arrow_py38():
class StructModel(pydantic.BaseModel):
a: str
b: Optional[float]
class TestModel(pydantic.BaseModel):
id: int
s: str
vec: List[float]
li: List[int]
lili: List[List[float]]
litu: List[Tuple[float, float]]
opt: Optional[str] = None
st: StructModel
dt: date
dtt: datetime
dt_with_tz: datetime = Field(json_schema_extra={"tz": "Asia/Shanghai"})
# d: dict
# TODO: test we can actually convert the model to Arrow data.
# m = TestModel(
# id=1,
# s="hello",
# vec=[1.0, 2.0, 3.0],
# li=[2, 3, 4],
# lili=[[2.5, 1.5], [3.5, 4.5], [5.5, 6.5]],
# litu=[(2.5, 1.5), (3.5, 4.5), (5.5, 6.5)],
# st=StructModel(a="a", b=1.0),
# dt=date.today(),
# dtt=datetime.now(),
# dt_with_tz=datetime.now(pytz.timezone("Asia/Shanghai")),
# )
schema = pydantic_to_schema(TestModel)
expect_schema = pa.schema(
[
pa.field("id", pa.int64(), False),
pa.field("s", pa.utf8(), False),
pa.field("vec", pa.list_(pa.float64()), False),
pa.field("li", pa.list_(pa.int64()), False),
pa.field("lili", pa.list_(pa.list_(pa.float64())), False),
pa.field("litu", pa.list_(pa.list_(pa.float64())), False),
pa.field("opt", pa.utf8(), True),
pa.field(
"st",
pa.struct(
[pa.field("a", pa.utf8(), False), pa.field("b", pa.float64(), True)]
),
False,
),
pa.field("dt", pa.date32(), False),
pa.field("dtt", pa.timestamp("us"), False),
pa.field("dt_with_tz", pa.timestamp("us", tz="Asia/Shanghai"), False),
]
)
assert schema == expect_schema
def test_nullable_vector():
class NullableModel(pydantic.BaseModel):
vec: Vector(16, nullable=False)
schema = pydantic_to_schema(NullableModel)
assert schema == pa.schema([pa.field("vec", pa.list_(pa.float32(), 16), False)])
class DefaultModel(pydantic.BaseModel):
vec: Vector(16)
schema = pydantic_to_schema(DefaultModel)
assert schema == pa.schema([pa.field("vec", pa.list_(pa.float32(), 16), True)])
class NotNullableModel(pydantic.BaseModel):
vec: Vector(16)
schema = pydantic_to_schema(NotNullableModel)
assert schema == pa.schema([pa.field("vec", pa.list_(pa.float32(), 16), True)])
def test_bare_vector_raises_clear_error():
namespace = {
"__name__": "test_model_without_pyarrow",
"LanceModel": LanceModel,
"Vector": Vector,
}
with pytest.raises(TypeError, match=r"Vector must be parameterized.*Vector\(128\)"):
exec("class TestModel(LanceModel):\n vector: Vector", namespace)
def test_embedding_vector_list_annotation():
embedding = MockTextEmbeddingFunction.create()
class StaticTypingModel(LanceModel):
text: str = embedding.SourceField()
vector: list[float] = embedding.VectorField()
schema = pydantic_to_schema(StaticTypingModel)
assert schema == pa.schema(
[
pa.field("text", pa.utf8(), False),
pa.field("vector", pa.list_(pa.float32(), embedding.ndims()), True),
]
)
model = StaticTypingModel(text="hello", vector=[0.0] * embedding.ndims())
assert model.vector == [0.0] * embedding.ndims()
def test_fixed_size_list_field():
class TestModel(pydantic.BaseModel):
vec: Vector(16)
li: List[int]
data = TestModel(vec=list(range(16)), li=[1, 2, 3])
assert json.loads(data.model_dump_json()) == {
"vec": list(range(16)),
"li": [1, 2, 3],
}
schema = pydantic_to_schema(TestModel)
assert schema == pa.schema(
[
pa.field("vec", pa.list_(pa.float32(), 16)),
pa.field("li", pa.list_(pa.int64()), False),
]
)
json_schema = TestModel.model_json_schema()
assert json_schema == {
"properties": {
"vec": {
"items": {"type": "number"},
"maxItems": 16,
"minItems": 16,
"title": "Vec",
"type": "array",
},
"li": {"items": {"type": "integer"}, "title": "Li", "type": "array"},
},
"required": ["vec", "li"],
"title": "TestModel",
"type": "object",
}
def test_fixed_size_list_validation():
class TestModel(pydantic.BaseModel):
vec: Vector(8)
with pytest.raises(pydantic.ValidationError):
TestModel(vec=range(9))
with pytest.raises(pydantic.ValidationError):
TestModel(vec=range(7))
TestModel(vec=range(8))
def test_lance_model():
class TestModel(LanceModel):
vector: Vector(16) = Field(default=[0.0] * 16)
li: List[int] = Field(default=[1, 2, 3])
schema = pydantic_to_schema(TestModel)
assert schema == TestModel.to_arrow_schema()
assert TestModel.field_names() == ["vector", "li"]
t = TestModel()
assert t == TestModel(vec=[0.0] * 16, li=[1, 2, 3])
def test_optional_nested_model():
class WAMedia(BaseModel):
url: str
mimetype: str
filename: Optional[str]
error: Optional[str]
data: bytes
class WALocation(BaseModel):
description: Optional[str]
latitude: str
longitude: str
class ReplyToMessage(BaseModel):
id: str
participant: str
body: str
class Message(BaseModel):
id: str
timestamp: int
from_: str
fromMe: bool
to: str
body: str
hasMedia: Optional[bool]
media: WAMedia
mediaUrl: Optional[str]
ack: Optional[int]
ackName: Optional[str]
author: Optional[str]
location: Optional[WALocation]
vCards: Optional[List[str]]
replyTo: Optional[ReplyToMessage]
class AnyEvent(LanceModel):
id: str
session: str
metadata: Optional[str] = None
engine: str
event: str
class MessageEvent(AnyEvent):
payload: Message
schema = pydantic_to_schema(MessageEvent)
payload = schema.field("payload")
assert payload.type == pa.struct(
[
pa.field("id", pa.utf8(), False),
pa.field("timestamp", pa.int64(), False),
pa.field("from_", pa.utf8(), False),
pa.field("fromMe", pa.bool_(), False),
pa.field("to", pa.utf8(), False),
pa.field("body", pa.utf8(), False),
pa.field("hasMedia", pa.bool_(), True),
pa.field(
"media",
pa.struct(
[
pa.field("url", pa.utf8(), False),
pa.field("mimetype", pa.utf8(), False),
pa.field("filename", pa.utf8(), True),
pa.field("error", pa.utf8(), True),
pa.field("data", pa.binary(), False),
]
),
False,
),
pa.field("mediaUrl", pa.utf8(), True),
pa.field("ack", pa.int64(), True),
pa.field("ackName", pa.utf8(), True),
pa.field("author", pa.utf8(), True),
pa.field(
"location",
pa.struct(
[
pa.field("description", pa.utf8(), True),
pa.field("latitude", pa.utf8(), False),
pa.field("longitude", pa.utf8(), False),
]
),
True, # Optional
),
pa.field("vCards", pa.list_(pa.utf8()), True),
pa.field(
"replyTo",
pa.struct(
[
pa.field("id", pa.utf8(), False),
pa.field("participant", pa.utf8(), False),
pa.field("body", pa.utf8(), False),
]
),
True,
),
]
)
def test_multi_vector():
class TestModel(pydantic.BaseModel):
vec: MultiVector(8)
schema = pydantic_to_schema(TestModel)
assert schema == pa.schema(
[pa.field("vec", pa.list_(pa.list_(pa.float32(), 8)), True)]
)
with pytest.raises(pydantic.ValidationError):
TestModel(vec=[[1.0] * 7])
with pytest.raises(pydantic.ValidationError):
TestModel(vec=[[1.0] * 9])
TestModel(vec=[[1.0] * 8])
TestModel(vec=[[1.0] * 8, [2.0] * 8])
TestModel(vec=[])
def test_multi_vector_nullable():
class NullableModel(pydantic.BaseModel):
vec: MultiVector(16, nullable=False)
schema = pydantic_to_schema(NullableModel)
assert schema == pa.schema(
[pa.field("vec", pa.list_(pa.list_(pa.float32(), 16)), False)]
)
class DefaultModel(pydantic.BaseModel):
vec: MultiVector(16)
schema = pydantic_to_schema(DefaultModel)
assert schema == pa.schema(
[pa.field("vec", pa.list_(pa.list_(pa.float32(), 16)), True)]
)
def test_multi_vector_in_lance_model():
class TestModel(LanceModel):
id: int
vectors: MultiVector(16) = Field(default=[[0.0] * 16])
schema = pydantic_to_schema(TestModel)
assert schema == TestModel.to_arrow_schema()
assert TestModel.field_names() == ["id", "vectors"]
t = TestModel(id=1)
assert t.vectors == [[0.0] * 16]
def test_aliases_in_lance_model(mem_db):
data = [
{"vector": [3.1, 4.1], "item": "foo", "price": 10.0},
{"vector": [5.9, 6.5], "item": "bar", "price": 20.0},
]
tbl = mem_db.create_table("items", data=data)
class TestModel(LanceModel):
name: str = Field(alias="item")
price: float
distance: float = Field(alias="_distance")
model = (
tbl.search([5.9, 6.5])
.distance_type("cosine")
.limit(1)
.to_pydantic(TestModel)[0]
)
assert hasattr(model, "name")
assert hasattr(model, "distance")
assert model.distance < 0.01
@pytest.mark.asyncio
async def test_aliases_in_lance_model_async(mem_db_async):
data = [
{"vector": [8.3, 2.5], "item": "foo", "price": 12.0},
{"vector": [7.7, 3.9], "item": "bar", "price": 11.2},
]
tbl = await mem_db_async.create_table("items", data=data)
class TestModel(LanceModel):
name: str = Field(alias="item")
price: float
distance: float = Field(alias="_distance")
model = (
await tbl.vector_search([7.7, 3.9])
.distance_type("cosine")
.limit(1)
.to_pydantic(TestModel)
)[0]
assert hasattr(model, "name")
assert hasattr(model, "distance")
assert model.distance < 0.01
def test_enum_types():
"""Enum fields should map to the Arrow type of their value (issue #1846)."""
class StrStatus(str, Enum):
PENDING = "pending"
RUNNING = "running"
DONE = "done"
class IntPriority(int, Enum):
LOW = 1
MEDIUM = 2
HIGH = 3
class TestModel(pydantic.BaseModel):
status: StrStatus
priority: IntPriority
opt_status: Optional[StrStatus] = None
schema = pydantic_to_schema(TestModel)
assert schema.field("status").type == pa.dictionary(pa.int32(), pa.utf8())
assert schema.field("priority").type == pa.int64()
assert schema.field("opt_status").type == pa.dictionary(pa.int32(), pa.utf8())
assert schema.field("opt_status").nullable