Blocks Slider change() outputs incorrect value on drag

[mindwrapped]

Describe the bug

If you click and drag on the slider then it will pass an incorrect value to change().

If you only click on the slider then it will pass the correct value to change().

Is there an existing issue for this?

• I have searched the existing issues

Reproduction

https://huggingface.co/spaces/mindwrapped/blocks-slider-test

Click and drag -> incorrect value (old value, not the current one displayed on the slider)
Click -> correct value (same value as on the slider)

import gradio as gr

def update_value(val):
  return f'Value is set to {val}'

demo = gr.Blocks()

with demo:
  inp = gr.Slider(0, 100, label='Value')
  md = gr.Markdown('Select a value')

  inp.change(fn=update_value, inputs=inp, outputs=md)

demo.launch()

Screenshot

Logs

From HF Spaces:

Running on local URL:  http://localhost:7860/

To create a public link, set `share=True` in `launch()`.

System Info

Huggingface Spaces
Gradio: 3.0.10

Severity

blocking upgrade to latest gradio version

[cyyeh]

I found this issue happened when it is deployed using Spaces, there's no issue if I run this application locally.

[aliabid94]

Will fix, thanks for raising this issue!

[NimaBoscarino]

I'm running into this as well on Gradio 3.3. Here's a notebook to reproduce: https://colab.research.google.com/drive/1JoDcK5R8lcA7Ty4-zlXnQNBwKXdfgRpb?usp=sharing

Same as mentioned above, works fine locally but on Colab + Spaces it's broken.

[abidlabs]

This should be solved by #2436, so moving to the 4.0 milestone

[abidlabs]

Special case of #1954, so closing this issue

[axkoenig]

Hi there,
I think the issue still persists when there is some lag introduced inside the update_value function mentioned above.
Consider the below example:

import gradio as gr

def update_value(val):
  import time
  time.sleep(2) # simulate ML model inference
  return f'Value is set to {val}'

demo = gr.Blocks()

with demo:
  inp = gr.Slider(0, 100, label='Value')
  md = gr.Markdown('Select a value')

  inp.change(fn=update_value, inputs=inp, outputs=md)

demo.launch()

If you drag the slider quickly from left to right, you'll end up with the slider evaluating to 1, but its final value is 46.

I think this is because under the hood the .update() method is called when the slider is starting to be dragged, however not when it is released. Is there a way to call update again once the slider is released?

I'm on the latest gradio version

pip list | grep gradio
gradio                                3.32.0
gradio_client                         0.2.5