Fix programmatic tab selection

[aliabid94]

selected was not being respected for tabitems, because the id property of a tabitem was being overwritten internally. Renamed internal use of id to _id.

Test with:

import gradio as gr

def select_c():
    return gr.Tabs(selected="c")

with gr.Blocks() as demo:
    with gr.Tabs(selected="b") as tabs:
        with gr.Tab("A", id="a"):
            gr.Markdown("## A")
        with gr.Tab("B", id="b"):
            gr.Markdown("## B")
        with gr.Tab("C", id="c"):
            gr.Markdown("## C")

    btn = gr.Button("Switch to tab C")
    btn.click(select_c, None, tabs)

demo.launch()

Fixes: #7726

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---

Install Gradio from this PR

pip install https://gradio-builds.s3.amazonaws.com/56c24885b35b84121678e006a5094952ca9d67d2/gradio-4.25.0-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@56c24885b35b84121678e006a5094952ca9d67d2#subdirectory=client/python"

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Package	Version
@gradio/app	patch
gradio	patch

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Fix programmatic tab selection

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[pngwn]

Ah nice catch. Thanks @aliabid94!

We should probably lint against 'shadowing' variables. I wonder if this fixes #7786 as well?

[freddyaboulton]

Nice @aliabid94 ! Can we add a test for this? It's regressed before

[aliabid94]

Added tests. While I was adding tests, I caught an error that wouldn't show up in dev mode for some reason: If a gr.Tabs() had selected= set to a value in its constructor, than any event listener trigger that would cause a redraw would reset the gr.Tabs to the selected tab. I made changes to Tab.svelte to fix this, @pngwn if you could just take a quick pass at it again.

[aliabid94]

actually my solution won't work in the case that an app programmatically tries to set the selected tab to the same tab a second time after a user moved away from that tab. Is there any way for gradio to know if the selected tab being passed is the result of an event listener output, or just a redraw resetting the prop?

[pngwn]

What is the actually problem, sorry. In principle we shouldn't need to know the difference.

[hannahblair]

Yep, when selecting away from Tab C, I'm unable to select it again:

Sounds like the same problem you're referring to @aliabid94. However, removing the new logic that was added in Tabs.svelte seem to fix it. Do we need the old_selected_prop and _selected vars?

Edit: I realise you added these changes due to

Added tests. While I was adding tests, I caught an error that wouldn't show up in dev mode for some reason ...

[pngwn]

This feels like the accordion thing tbh. Gonna take a closer look.

[aliabid94]

Sorry let me clarify. The issue I was trying to fix with selected, _selected, and old_selected_prop is that event listeners were causing the component to re-render, which was causing the props to be reset to their set values. So the selected tab would get reset to the constructor-set value. So if there was a gr.Tabs(selected="b") setting the default to "b", and a user clicked away to tab "a", when an event listener triggered a re-render, the tab would reset to "b".

[pngwn]

I see. That does sound very similar to the accordion issues where it resets to the default.

[pngwn]

@aliabid94 I have just opened #7963 to fix the accordion 'reset' issue, and this feels similar. When that is merged in i think if you merge main into this it may fix the remaining issue you are having.

[pngwn]

#7963 is merged now, I've updated this branch with main. Could you retest now @aliabid94?

[aliabid94]

Works great, thanks @pngwn!

[pngwn]

Looks great! Thanks for fixing this and adding those extra tests @aliabid94!

[arose26]

So, how do I change the active tab programmatically? (not from a button, just from code).
I've tried changing the tab instance's 'selected' property directly but that only works BEFORE calling launch. After launch, it doesn't do the job. gr.Tabs.update(selected=newid) doesn't work either.
I want to change selected tab in real time, from python code.