Switching Branches Keeps Files

[mlucool]

Description

When switching branches - jupyterlab git should close all open files that are not present in the other branch.

Reproduce

1. Create branch A
2. Commit a notebook to it (N1) and leave that notebook open in lab
3. Create a new branch from A, called B (which now has N1) and switch to B
4. Create a second notebook (N2) commit that and leave it open in lab (here you are in B with N1/N2 committed and opened in Lab)
5. Switch to A (either via CLI or UI).
6. If autosave enabled, wait for it to be autosaved (you can also just save it)
7. Try to switch to branch B again

This creates an issue because:

1. Switching branches fails because my untracked file would be overwritten with itself
2. It makes it easier to get confused

Expected behavior

Any committed file should be closed when switching branches if it is not in the new branch (i. e. if git removes when switching). Ideally this is true both for the CLI and the UI, but I think it's ok to only fix the UI if the CLI variant is too hard/out of scope.

Maybe this is a jupyterlab request, as it could also be thought of as any file removed from disk should close in lab (possible with a warning).

Context

Lab 2.3.0a1
Jupyterlab-Git: 0.23.1

[telamonian]

If you delete a file outside of jlab, I'm going to say that it's a feature (and a common one for IDEs, at that) and not a bug that the in-memory copy in jlab stays open. There's lots of use cases for this, including the obvious one of recovering from accidental file deletion.

However, I just tested and confirmed that if you delete a file from within the jlab filebrowser, any open tabs in the jlab mainarea associated with said file will indeed close. So jlab-git will need some similar special handling for closing tabs when a file is "deleted" by a branch change (or other git HEAD switch action).

Overall, I think @mlucool suggestion is a good one. It should be implemented in the jlab-git extension (not as part of core), and only when the branch change is initiated using the jlab-git GUI. Changes made using the git CLI should be treated the same as any other external file operation (ie the in-memory copy of deleted files should remain open in jlab)

[fcollonval]

Providing pointer here:

The signal headChanged from the git model is emitted when switching branch. So looping through the opened files and closing those that are no more present should be done in reaction to that signal.

Note: this should be plugged in directly in the activate function of the extension where the model, the shell and the docmanager are available.

[sidiney-crescencio]

I think it might be related to the issue described here, what I also noticed is the following:

1. On branch A I add a new folder and some files
2. Checkout to branch B, the new folder from branch A will be visible until a browser refresh is done

Should I open a new issue for this scenario or is indeed covered on this one?

JupyterLab 3.0.15
JupyterLab-Git v0.30.1

[fcollonval]

Should I open a new issue for this scenario or is indeed covered on this one?

I opened a new issue.