Merge pull request #1026 from lsst-sqre/tickets/DM-44269

DM-44269: Remove workaround for FastAPI bug

src/gafaelfawr/main.py

@@ -9,12 +9,8 @@
 from pathlib import Path
 
 import structlog
-from fastapi import FastAPI, Request, status
-from fastapi.encoders import jsonable_encoder
-from fastapi.exceptions import RequestValidationError
-from fastapi.responses import JSONResponse
+from fastapi import FastAPI
 from fastapi.staticfiles import StaticFiles
-from pydantic_core import PydanticUndefinedType
 from safir.dependencies.db_session import db_session_dependency
 from safir.dependencies.http_client import http_client_dependency
 from safir.fastapi import ClientRequestError, client_request_error_handler
@@ -185,26 +181,4 @@ async def lifespan(app: FastAPI) -> AsyncIterator[None]:
     # Handle exceptions descended from ClientRequestError.
     app.exception_handler(ClientRequestError)(client_request_error_handler)
 
-    # This is a temporary workaround for a bug in FastAPI handling Pydantic
-    # validation errors when a list query parameter is not specified. See
-    # https://github.com/tiangolo/fastapi/issues/9920
-    #
-    # This should be removed when that issue is fixed.
-    @app.exception_handler(RequestValidationError)
-    async def request_validation_exception_handler(
-        request: Request, exc: RequestValidationError
-    ) -> JSONResponse:
-        """Handle request validation errors."""
-        return JSONResponse(
-            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
-            content={
-                "detail": jsonable_encoder(
-                    exc.errors(),
-                    custom_encoder={
-                        PydanticUndefinedType: lambda _: None,
-                    },
-                )
-            },
-        )
-
     return app