#6669 [BUG] Deserializing Pydantic models with FlyteFile fields creates FlyteFile instances that can't be serialized again. Issue created by markus1978 ### Flyte & Flytekit version This can be reproduced with flytekit==1.16.5. ### Describe the bug FlyteFiles can be used in Pydantic models. When you serialize and deserialize a Pydantic model that uses FlyteFile on its fields, the resulting FlyteFile instances are "broken". Serializing them again (both via Pydantic or Flyte) causes an exception. This is a minimal example to reproduce the issue: from pydantic import BaseModel from flytekit import FlyteFile class MyModel(BaseModel): file: FlyteFile model = MyModel(file=FlyteFile.from_source("gs://does/not/matter.txt")) deserialized_model = MyModel.model_validate(model.model_dump()) deserialized_model.model_dump() # <- this always causes the exception This is the exception:

╭─────────────────────────────────────── Traceback (most recent call last) ───────────────────────────────────────╮
│ /home/coder/platform/.venv/lib/python3.12/site-packages/flytekit/types/file/file.py:196 in serialize_flyte_file │
│                                                                                                                 │
│ ❱ 196 │   │   lv = FlyteFilePathTransformer().to_literal(                                                       │
│                                                                                                                 │
│ /home/coder/platform/.venv/lib/python3.12/site-packages/flytekit/core/type_engine.py:318 in to_literal          │
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│ ❱  318 │   │   result = synced(ctx, python_val, python_type, expected)                                          │
│                                                                                                                 │
│ /home/coder/platform/.venv/lib/python3.12/site-packages/flytekit/utils/asyn.py:113 in wrapped                   │
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│ ❱ 113 │   │   │   return self.run_sync(coro_func, *args, **kwargs)                                              │
│                                                                                                                 │
│ /home/coder/platform/.venv/lib/python3.12/site-packages/flytekit/utils/asyn.py:106 in run_sync                  │
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│ ❱ 106 │   │   return self._runner_map[name].run(coro)                                                           │
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│ /home/coder/platform/.venv/lib/python3.12/site-packages/flytekit/utils/asyn.py:85 in run                        │
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│ ❱  85 │   │   res = fut.result(None)                                                                            │
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│ /usr/lib/python3.12/concurrent/futures/_base.py:456 in result                                                   │
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│ ❱ 456 │   │   │   │   │   return self.__get_result()                                                            │
│                                                                                                                 │
│ /usr/lib/python3.12/concurrent/futures/_base.py:401 in __get_result                                             │
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│ ❱ 401 │   │   │   │   raise self._exception                                                                     │
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│ /home/coder/platform/.venv/lib/python3.12/site-packages/flytekit/types/file/file.py:586 in async_to_literal     │
│                                                                                                                 │
│ ❱ 586 │   │   │   if python_val._remote_source is not None:                                                     │
╰─────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
AttributeError: 'FlyteFile' object has no attribute '_remote_source'

The above exception was the direct cause of the following exception:

╭─────────────────────────────────────── Traceback (most recent call last) ───────────────────────────────────────╮
│ in <module>:11                                                                                                  │
│                                                                                                                 │
│ ❱ 11 deserialized_model.model_dump()  # <- this always causes the exception                                     │
│                                                                                                                 │
│ /home/coder/platform/.venv/lib/python3.12/site-packages/pydantic/main.py:464 in model_dump                      │
│                                                                                                                 │
│ ❱  464 │   │   return self.__pydantic_serializer__.to_python(                                                   │
╰─────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
PydanticSerializationError: Error calling function `serialize_flyte_file`: AttributeError: 'FlyteFile' object has 
no attribute '_remote_source'

### Expected behavior The expected bahavior is that a serialized and then deserialized FlyteFile works for all practical purpose as the original. This means i can serialize, deserialize, and serialize it again. ### Additional context to reproduce No response ### Screenshots No response ### Are you sure this issue hasn't been raised already? • Yes ### Have you read the Code of Conduct? • Yes flyteorg/flyte