state.change listener with deep hash check

[aliabid94]

state.change event listeners now do "deep checks", by deep hashing the old value. This makes @gr.render logic much cleaner. See demo/todo_list changes to see how much simpler the code is now because state values can be edited directly to induce a change.

Closes: https://github.com/gradio-app/gradio/issues/8436

[gradio-pr-bot]

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---

Install Gradio from this PR

pip install https://gradio-builds.s3.amazonaws.com/18ae92782cf6061a6ac1055698779537e9e17b34/gradio-4.32.2-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@18ae92782cf6061a6ac1055698779537e9e17b34#subdirectory=client/python"

Install Gradio JS Client from this PR

npm install https://gradio-builds.s3.amazonaws.com/18ae92782cf6061a6ac1055698779537e9e17b34/gradio-client-0.20.1.tgz

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
gradio	minor

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With the following changelog entry.

state.change listener with deep hash check

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[pngwn]

How expensive is this?

[aliabid94]

How expensive is this?

Pretty cheap I would think. It runs a hash function for every element in the nested object, and only gets run if there's a state change listener involved. In regular python the same hash function is called whenever you add any element to a dictionary or a set, so hashing is already quite optimized.

[abidlabs]

It might be worth adding a note on the State.change() event listener docstring that this could get expensive if the State object is a sequence with a large number of elements

[aliabid94]

It might be worth adding a note on the State.change() event listener docstring that this could get expensive if the State object is a sequence with a large number of elements

I don't think it's possible to directly add docs to the event of a single component. Regardless will update docs and guides on gr.State in a follow up PR.