App configuration as inline metadata (i.e., TOML comment block)?

[manzt]

First of all, I want to say that I really love the MEPs. These are excellent reads and really give me a sense of the foundations and considerations that have gone into marimo. Kudos!

I saw in MEP 4 that the idea for putting the app config as TOML was ultimately decided against because it:

"requires committing and shipping the TOML file for settings to be reproducible. This was a dealbreaker."

I'm guessing that this decision was before PEP 723, and now there is some precedent for putting tool-specific metadata in the comment block as well. For example, with uv you can add exclude-newer metadata.

# /// script
# requires-python = ">=3.13"
# dependencies = [
#     "numpy",
# ]
#
# [tool.uv]
# exclude-newer = "2024-12-05T22:06:45.27544-05:00"
# ///

def main() -> None:
    print("Hello from foo.py!")


if __name__ == "__main__":
    main()

I'm not saying this should be where marimo app configuration lives, but moreover just pointing out that the original con/dealbreaker wrt to more static app configuration may no longer hold. Thought I'd open an issue for discussion. A [tool.marimo] block could be interesting!

[mscolnick]

Yes, we definitely now ship toml with our notebooks (only optionally), for package requirements.

Good timing on this issue/topic though, since I am adding [tool.marimo] support to the local pyproject.toml: marimo-team/marimo#3071

I was planning in a followup to also read from the current file for additional user-config overrides as well, and they all merge back up. You can probably see where this would go (and how easy it is):

def get_default_config_manager(*, current_path: Optional[str]) -> MarimoConfigManager:
    # Current path should be the notebook file
    # If it's not known, use the current working directory
    if current_path is None:
        current_path = os.getcwd()
    return MarimoConfigManager(
        UserConfigManager(),
        ProjectConfigManager(current_path),
        # add more overrides here
    )

Note: this would be for user-configuration (theme, display options, runtime, etc). and not the existing app-configuration (title, layout).

I am not sure how these evolve overtime, but for now, i think it makes sense to allow user-configs (e.g. [tool.marimo]) to be set in marimo files in the same vain of "self-containment"