list[File] not handled correctly when one file is provided

[robocattyball]

Validation fails when one file is provided in file.

from pydantic import BaseModel
from quart import Quart
from quart_schema import QuartSchema
from quart_schema.pydantic import File

app = Quart(__name__)
app.config["MAX_CONTENT_LENGTH"] = 150 * 1024 * 1024  # 150MB limit for rag file upload
QuartSchema(app)

class SomeOtherArguments(BaseModel):
    name: str

class Upload(SomeOtherArguments):
    file: list[File]  # Work around: `list[File] | File`

@rag_blueprint.post("/upload")
@validate_request(Upload, source=DataSource.FORM_MULTIPART)
async def rag_create(data: Upload):
    return {}, 200

Error:

{
  "errors": "74956 validation errors for Upload\nfile.0\n  Value error, Expected FileStorage, received: <class 'bytes'> ...
}

When the work around list[File] | File is used, the docs no longer handled the filed as a file, but just as a string:

[robocattyball]

Version:

Quart = "0.19.8"
"quart-schema[pydantic]" = "==0.20.0"
pydantic = "2.5.3"

[sbp]

I've been doing something like this:

    files_obj = await request.files

    list_fields = set()
    for field_name, field_info in UploadForm.model_fields.items():
        annotation = field_info.annotation
        if (annotation is not None) and hasattr(annotation, "__origin__"):
            if annotation.__origin__ is list:
                list_fields.add(field_name)

    data_dict = {}
    for key in files_obj:
        if key in list_fields:
            data_dict[key] = files_obj.getlist(key)
        else:
            data_dict[key] = files_obj[key]

    data = UploadForm(**data_dict)

But this only works for Pydantic v2, and doesn't handle cases such as when list[File] | File is used, which is the very workaround mentioned by @robocattyball. I hope this is a useful contribution anyway.