@dataloader decorator doesn't work when using full type annotations

[jlopezpena]

Current behavior

If I use full type annotations for return types, like dict[str, Any] instead of dict, the @dataloader decorator raises an error

Stack Traces

Traceback (most recent call last):
  File "/Users/jlopezpena/Code/RA/pipelines/main.py", line 3, in <module>
    import functions
  File "/Users/jlopezpena/Code/RA/pipelines/functions.py", line 6, in <module>
    @dataloader()
     ~~~~~~~~~~^^
  File "/Users/jlopezpena/Code/RA/pipelines/.venv/lib/python3.13/site-packages/hamilton/function_modifiers/base.py", line 60, in replace__call__
    return call_fn(self, fn)
  File "/Users/jlopezpena/Code/RA/pipelines/.venv/lib/python3.13/site-packages/hamilton/function_modifiers/base.py", line 102, in __call__
    self.validate(fn)
    ~~~~~~~~~~~~~^^^^
  File "/Users/jlopezpena/Code/RA/pipelines/.venv/lib/python3.13/site-packages/hamilton/function_modifiers/adapters.py", line 752, in validate
    raise InvalidDecoratorException(
        f"Function: {fn.__qualname__} must return a tuple of type (SOME_TYPE, dict)."
    )
hamilton.function_modifiers.base.InvalidDecoratorException: Function: sample_dataloader must return a tuple of type (SOME_TYPE, dict).

Screenshots

Steps to replicate behavior

Simple reproducing example:

# functions.py

from typing import Any

from hamilton.function_modifiers import dataloader


@dataloader()
def sample_dataloader() -> tuple[list[str], dict[str, Any]]:
    return ["a", "b", "c"], {}

# main.py

from hamilton import driver

import functions

if __name__ == "__main__":
    dr = driver.Builder().with_modules(functions)

Then running the main script with python main.py raises the error shown in stacktrace and screenshot.

Library & System Information

Python 3.12.7, Hamilton 1.85.0, error reproduced in Mac OS and Ubuntu Linux, running in a virtual environment that just contains hamilton and its dependencies

Expected behavior

The decorator accepts the stricter type as valid

Additional context

Not a big deal, but generally annoying in projects that use strict typing, as making hamilton happy forces to add a # type: ignore comment in every decorated function to prevent mypy from complaining.

[elijahbenizzy]

Hey! Fix is released in 1.85.1. Closing -- open up if you need anything else!