Two bugs for gr.HTML

[aliabid94]

Two annoying bugs fixed for gr.HTML:

1. Templating errors sometimes didn't show the error message, because both HTML and CSS were being templated, and if only one failed, eg.g HTML failed but CSS passed and CSS was templated after HTML, we would assume that there was no error. Now we check to make sure both CSS and HTML templating work
2. If a gr.HTML had an object-type property, the first update didn't work because the update check logic used to compare old_props with props had the issue that initially, old_props = props, so updating one updated the other. Now we make a deep copy of props and set that to old props so that they work.

You can see the last two items in the super_html demo to demonstrate these changes,

[gradio-pr-bot]

🪼 branch checks and previews

•	Name	Status	URL
	Spaces	ready!	Spaces preview
	Website	ready!	Website preview
🦄	Changes	detected!	Details

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Install Gradio from this PR

pip install https://gradio-pypi-previews.s3.amazonaws.com/41222f964b2ae87b120588a2548b2f3fa23b58f0/gradio-6.1.0-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@41222f964b2ae87b120588a2548b2f3fa23b58f0#subdirectory=client/python"

Install Gradio JS Client from this PR

npm install https://gradio-npm-previews.s3.amazonaws.com/41222f964b2ae87b120588a2548b2f3fa23b58f0/gradio-client-2.0.0.tgz

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
@gradio/html	patch
gradio	patch

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• Two bugs for gr.HTML

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✅ Changeset approved by @freddyaboulton

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[abidlabs]

imo better to show both errors if there are both html and css errors, otherwise a user might think that the fix for the html error caused the css error.

[freddyaboulton]

Yea I think displaying all the error info is useful to users/developers

[abidlabs]

Nice @aliabid94 changes look good but even after pulling the latest version of this PR and rebuilding the frontend, I see that the the first update doesn't work:

Screen.Recording.2025-12-18.at.12.46.58.PM.mov

[freddyaboulton]

I see the correct behavior in the dev server. This LGTM @aliabid94 but would be good to check with @abidlabs !

[freddyaboulton]

Merging for the release! Thanks @aliabid94