Moved conversion logic to `_extract_form_body`, added test to cover case with dependency

fastapi/dependencies/utils.py

@@ -54,6 +54,7 @@ from fastapi.concurrency import (
     asynccontextmanager,
     contextmanager_in_threadpool,
 )
+from fastapi.datastructures import UploadFile as FastAPIUploadFile
 from fastapi.dependencies.models import Dependant, SecurityRequirement
 from fastapi.exceptions import DependencyScopeError
 from fastapi.logger import logger
@@ -875,17 +876,19 @@ async def _extract_form_body(
     for field in body_fields:
         value = _get_multidict_value(field, received_body)
         field_info = field.field_info
-        if (
+        if (  # fmt: skip
             isinstance(field_info, (params.File, temp_pydantic_v1_params.File))
-            and is_bytes_field(field)
             and isinstance(value, UploadFile)
         ):
+            if is_bytes_field(field):
                 value = await value.read()
-        elif (
-            is_bytes_sequence_field(field)
-            and isinstance(field_info, (params.File, temp_pydantic_v1_params.File))
+            else:
+                value = FastAPIUploadFile.from_starlette(value)
+        elif (  # fmt: skip
+            isinstance(field_info, (params.File, temp_pydantic_v1_params.File))
             and value_is_sequence(value)
         ):
+            if is_bytes_sequence_field(field):
                 # For types
                 assert isinstance(value, sequence_types)  # type: ignore[arg-type]
                 results: List[Union[bytes, str]] = []
@@ -900,6 +903,12 @@ async def _extract_form_body(
                     for sub_value in value:
                         tg.start_soon(process_fn, sub_value.read)
                 value = serialize_sequence_value(field=field, value=results)
+            else:
+                value = [
+                    FastAPIUploadFile.from_starlette(sub_value)
+                    for sub_value in value
+                    if isinstance(sub_value, UploadFile)
+                ]
         if value is not None:
             values[field.alias] = value
     for key, value in received_body.items():

fastapi/routing.py

@@ -34,7 +34,7 @@ from fastapi._compat import (
     _normalize_errors,
     lenient_issubclass,
 )
-from fastapi.datastructures import Default, DefaultPlaceholder, UploadFile
+from fastapi.datastructures import Default, DefaultPlaceholder
 from fastapi.dependencies.models import Dependant
 from fastapi.dependencies.utils import (
     _should_embed_body_fields,
@@ -65,7 +65,6 @@ from starlette import routing
 from starlette._exception_handler import wrap_app_handling_exceptions
 from starlette._utils import is_async_callable
 from starlette.concurrency import run_in_threadpool
-from starlette.datastructures import UploadFile as StarletteUploadFile
 from starlette.exceptions import HTTPException
 from starlette.requests import Request
 from starlette.responses import JSONResponse, Response
@@ -287,19 +286,6 @@ async def run_endpoint_function(
     # facilitate profiling endpoints, since inner functions are harder to profile.
     assert dependant.call is not None, "dependant.call must be a function"
 
-    # Convert all Starlette UploadFiles to FastAPI UploadFiles
-    for key, value in values.items():
-        if isinstance(value, StarletteUploadFile) and not isinstance(value, UploadFile):
-            values[key] = UploadFile.from_starlette(value)
-        elif isinstance(value, list):
-            values[key] = [
-                UploadFile.from_starlette(item)
-                if isinstance(item, StarletteUploadFile)
-                and not isinstance(item, UploadFile)
-                else item
-                for item in value
-            ]
-
     if is_coroutine:
         return await dependant.call(**values)
     else:

tests/test_request_uploadfile_type.py

@@ -1,7 +1,8 @@
 import io
 from typing import Any, Dict, List
 
-from fastapi import FastAPI, File, UploadFile
+import pytest
+from fastapi import Depends, FastAPI, File, UploadFile
 from fastapi.testclient import TestClient
 from starlette.datastructures import UploadFile as StarletteUploadFile
 
@@ -33,10 +34,48 @@ async def uploadfiles(
     ]
 
 
-def test_uploadfile_type() -> None:
+async def get_uploadfile_info(uploadfile: UploadFile = File(...)) -> Dict[str, Any]:
+    return {
+        "filename": uploadfile.filename,
+        "is_fastapi_uploadfile": isinstance(uploadfile, UploadFile),
+        "is_starlette_uploadfile": isinstance(uploadfile, StarletteUploadFile),
+        "class": f"{uploadfile.__class__.__module__}.{uploadfile.__class__.__name__}",
+    }
+
+
+@app.post("/uploadfile-dep")
+async def uploadfile_dep(
+    uploadfile_info: Dict[str, Any] = Depends(get_uploadfile_info),
+) -> Dict[str, Any]:
+    return uploadfile_info
+
+
+async def get_uploadfiles_info(
+    uploadfiles: List[UploadFile] = File(...),
+) -> List[Dict[str, Any]]:
+    return [
+        {
+            "filename": uploadfile.filename,
+            "is_fastapi_uploadfile": isinstance(uploadfile, UploadFile),
+            "is_starlette_uploadfile": isinstance(uploadfile, StarletteUploadFile),
+            "class": f"{uploadfile.__class__.__module__}.{uploadfile.__class__.__name__}",
+        }
+        for uploadfile in uploadfiles
+    ]
+
+
+@app.post("/uploadfiles-dep")
+async def uploadfiles_dep(
+    uploadfiles_info: List[Dict[str, Any]] = Depends(get_uploadfiles_info),
+) -> List[Dict[str, Any]]:
+    return uploadfiles_info
+
+
+@pytest.mark.parametrize("endpoint", ["/uploadfile", "/uploadfile-dep"])
+def test_uploadfile_type(endpoint: str) -> None:
     client = TestClient(app)
     files = {"uploadfile": ("example.txt", io.BytesIO(b"test content"), "text/plain")}
-    response = client.post("/uploadfile/", files=files)
+    response = client.post(f"{endpoint}", files=files)
     data = response.json()
 
     assert data["filename"] == "example.txt"
@@ -45,19 +84,26 @@ def test_uploadfile_type() -> None:
     assert data["class"].startswith("fastapi.")
 
 
-def test_uploadfiles_type() -> None:
+@pytest.mark.parametrize("endpoint", ["/uploadfiles", "/uploadfiles-dep"])
+def test_uploadfiles_type(endpoint: str) -> None:
     client = TestClient(app)
     files = [
-        ("uploadfiles", ("example.txt", io.BytesIO(b"test content"), "text/plain"))
+        ("uploadfiles", ("example.txt", io.BytesIO(b"test content"), "text/plain")),
+        ("uploadfiles", ("example2.txt", io.BytesIO(b"test content"), "text/plain")),
     ]
-    response = client.post("/uploadfiles/", files=files)
+    response = client.post(f"{endpoint}", files=files)
     files_data = response.json()
 
-    assert len(files_data) == 1
+    assert len(files_data) == 2
 
-    data = files_data[0]
+    file1 = files_data[0]
+    assert file1["filename"] == "example.txt"
+    assert file1["is_fastapi_uploadfile"] is True
+    assert file1["is_starlette_uploadfile"] is True
+    assert file1["class"].startswith("fastapi.")
 
-    assert data["filename"] == "example.txt"
-    assert data["is_fastapi_uploadfile"] is True
-    assert data["is_starlette_uploadfile"] is True
-    assert data["class"].startswith("fastapi.")
+    file2 = files_data[1]
+    assert file2["filename"] == "example2.txt"
+    assert file2["is_fastapi_uploadfile"] is True
+    assert file2["is_starlette_uploadfile"] is True
+    assert file2["class"].startswith("fastapi.")