Orange spinner occasionally shows up when document loads

[jzhang20133]

[ellisonbg]

Thanks, here are a few references and hints that may help us track this down:

First, here is the logic in the mainareawidget that handles the spinner:

https://github.com/jupyterlab/jupyterlab/blob/9dbdb1d9c8134da36c08e1eae2211e5769f755c5/packages/apputils/src/mainareawidget.ts#L78

[ellisonbg]

Here is where MainAreaWidget is instantiated:

https://github.com/jupyterlab/jupyterlab/blob/9dbdb1d9c8134da36c08e1eae2211e5769f755c5/packages/docregistry/src/default.ts#L568

Notice how the options.reveal is extended with options.context.ready. I am guessing the the context is where things are going wrong (jupyter collaboration doesn't set reveal directly).

[dlqqq]

Took a look into this issue since I'm waiting to meet w/ Zach on the new Jupyter AI v3 strategy. Couple of observations:

1. I have noticed that this bug occurs when one tab has a document open, the server is restarted, and the new tab tries to load the same document as the previous tab. The bug goes away when you close all but one of the tabs trying to load a given document. I am still working on a way to reproduce this consistently.

2. The orange spinner delay is longer on *.chat files. The latency is likely proportional to file size.

3. Brian has correctly called out that the orange spinner only resolves when the document context sets the _ready promise. This occurs when the tab has completed the SS1 + SS2 handshake.