Add deque to serialization when Sequence is used as type hinting in V2 #7797
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Hi @XCanG, Thanks for filing this feature request. Could you attach the code that raised the above error? Thanks! |
sydney-runkle
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I thought it was self explanatory, but since it get down to this, there is minimal example with 2 cases: """
fastapi[all]==0.100.*
pydantic[email]==2.4.*
uvicorn[standard]==0.23.*
"""
from collections import deque
from collections.abc import Sequence
from fastapi import FastAPI
from fastapi.responses import HTMLResponse
from pydantic import BaseModel
class TestSubmodel(BaseModel):
id: int
name: str
class TestModel(BaseModel):
id: int
objects: Sequence[TestSubmodel]
app = FastAPI(debug=True)
model = TestModel(
id=1,
objects=deque([
TestSubmodel(id=1, name="test 1"),
TestSubmodel(id=2, name="test 2"),
]))
@app.get("/")
async def index() -> HTMLResponse:
"""Index page"""
return HTMLResponse("""
<a href="/docs">Swagger docs</a><br />
<a href="/test1">Test model with deque attribute (error)</a><br />
<a href="/test1_fixed">Test model with deque attribute (fixed)</a><br />
<a href="/test2">Test deque Sequence (error)</a><br />
<a href="/test2_fixed">Test deque Sequence (fixed)</a>
""")
@app.get("/test1")
async def get_model() -> TestModel:
"""Return TestModel with deque as Sequence (error)"""
print(model)
return model
@app.get("/test1_fixed")
async def get_model_fixed() -> TestModel:
"""Return TestModel with deque as Sequence (fixed)"""
model_copy = model.model_copy()
model_copy.objects = list(model_copy.objects)
print(model_copy)
return model_copy
@app.get("/test2")
async def get_model_sequence() -> Sequence[TestSubmodel]:
"""Return deque sequence of TestSubmodel (error)"""
print(model.objects)
return model.objects
@app.get("/test2_fixed")
async def get_model_sequence_fixed() -> Sequence[TestSubmodel]:
"""Return deque sequence of TestSubmodel (fixed)"""
submodel = list(model.objects)
print(submodel)
return submodel
if __name__ == "__main__":
import uvicorn
uvicorn.run(app, port=80) |
sydney-runkle
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awaiting author response
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Initial Checks
Description
It seems like Pydantic V1 had this support, but it was missed on Pydantic V2.
I using Pydantic with project on FastAPI.
In my case I'm working with fast stream of data, so I had to use
deque. As for the type hinting I usingSequence[MyModel]however Pydantic cannot recognize
dequeas validSequencetype, even if it is if you check withisinstance(my_deque, Sequence)->TrueWhen it trying to serialize, it throw error:
Project running in Docker with
requirements.txt:(not related requirements are omitted)
2.4.2 is current version
Affected Components
.model_dump()and.model_dump_json()model_construct(), pickling, private attributes, ORM modeThe text was updated successfully, but these errors were encountered: