Reset components to original state by setting value to None

[freddyaboulton]

Description

Fixes #1672

Previously, it was unclear how to reset components to their original state. As stated in the original issue, the "reset" value depended on the component, e.g. "" for textbox and [] for HightlightedText, and None would confusingly not do anything.

This PR makes it so that None will always reset the component to its unset state. The reason None would originally work is that the delete_none util method would delete the value field from the update dict if it was None.

To test:

• python demo/kitchen_sink_random/reset_component_demo.py and hit the Reset button
• unit tests

Checklist:

• I have performed a self-review of my own code
• My code follows the style guidelines of this project
• I have commented my code in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[github-actions]

All the demos for this PR have been deployed at https://huggingface.co/spaces/gradio-pr-deploys/pr-2044-all-demos

[freddyaboulton]

All components can now postprocess None

[freddyaboulton]

To reset the chatbot

[freddyaboulton]

None is no longer filtered out from the config. I think this is fine because the value is always postprocessed if None is not a "valid" value for the component.

[freddyaboulton]

Not sure if it's appropriate to reset these components with None

[abidlabs]

Suggest adding something in the docstring to mention the fact that we exclude keys whose name is "value" and the rationale (in case someone is reading the code later wonders why)

[abidlabs]

Nice fix @freddyaboulton! And great tests and demo. You might consider putting the demo in its own separate folder and in a file named run.py. There are a few places in the codebase where we assume demos are all in files called run.py, for example if we try to reference their code in the website. (Nit.)

[freddyaboulton]

Thanks for the review @abidlabs !