fix for report of auto-save not working?

[kellyrowland]

hello - did the fix proposed in https://discourse.jupyter.org/t/auto-save-does-not-always-work/24756 ever get submitted (and merged into) JupyterLab?

I have gotten a similar report from a user on one of our Jupyter instances (JupyterLab 4.2.4, JupyterHub 5.1.0), though we have not been able to reproduce the issue.

[kellyrowland]

I have been able to reproduce this behavior by turning off my computer's wifi connection, leaving it off for more than 2 minutes, then reconnecting and restarting the server. Any changes to the notebook in the server aren't saved, and the access/modify/change times of the notebook file don't change either.

This doesn't appear to happen on our Jupyter instance running JupyterLab 3.6.x, so I'm wondering if this is caused by the changes introduced in #10156.

[JasonWeill]

@kellyrowland Thank you for opening this issue! It doesn't look like the patch mentioned in that Discourse thread ever made it into mainline code, but we would welcome a pull request to add it in. Please let us know if you need any help or find any other issues. Thanks again!

[kellyrowland]

@JasonWeill thanks for taking a look here - it's not at all clear to me what was actually suggested in the linked Discourse post, so I'm not sure about a PR just yet.

@vkaidalov-rft could you weigh in on this as the author of #10156? I'm wondering if this check could be removed or if it would be preferable to decrease the save interval multiplier from 10 to something like 1.1.

[kellyrowland]

Thinking about this a little more, I don't think that changing the save interval multiplier would have any impact, because it seems that the call to _isConnectedCallback() in _setTimer returns false when the connection is lost for longer than the save interval and then fails to return true again when a connection is established (even after the save interval and then 10x the save interval):

[I 2024-09-25 10:45:24.596 ServerApp] Connecting to kernel a009b65b-603e-4dbe-959a-5db85d3c18e6.
[I 2024-09-25 10:47:22.447 ServerApp] Saving file at /global/homes/r/rowlandk/Untitled47.ipynb
[I 2024-09-25 10:47:22.451 ServerApp] Saving Untitled47.ipynb
[W 2024-09-25 10:49:24.505 ServerApp] WebSocket ping timeout after 119936 ms.
[I 2024-09-25 10:49:29.509 ServerApp] Starting buffering for a009b65b-603e-4dbe-959a-5db85d3c18e6:7b22b705-163a-4286-b415-239d9d0b2a5d
[W 2024-09-25 10:49:29.777 TerminalsExtensionApp] WebSocket ping timeout after 119895 ms.
[I 2024-09-25 11:21:27.452 ServerApp] Connecting to kernel a009b65b-603e-4dbe-959a-5db85d3c18e6.
[I 2024-09-25 11:21:27.454 ServerApp] Restoring connection for a009b65b-603e-4dbe-959a-5db85d3c18e6:7b22b705-163a-4286-b415-239d9d0b2a5d
[I 2024-09-25 11:24:37.895 ServerApp] Creating new notebook in /global/homes/r/rowlandk
[I 2024-09-25 11:24:37.906 ServerApp] Saving Untitled48.ipynb
[I 2024-09-25 11:24:39.276 ServerApp] Kernel started: 581074eb-042b-40fe-baa4-74270a83baa1

You can see here that I created Untitled47.ipynb, had it auto-save successfully, then disconnected for a period of time and then I don't see an auto-save, even after connection to the kernel is restored.

I am not familiar with TypeScript, so I'm not sure why this callback is not getting set back to true once the kernel connection has been reestablished. It seems to me like that a proper bugfix would have this working as expected (as opposed to a PR which simply removes the check), but I could really use some help from a developer with more TypeScript experience who could follow the logic in the code.