Impossible to update an open diff

Description

If you have a tab with the diff of a file and then make further changes to the file you will be unable to see these changes reflected in the diff until you close the diff tab and create a new one.

Clicking the diff action button again does not update the diff on account of the checking done here: https://github.com/jupyterlab/jupyterlab-git/blob/8d56986409461cd9968d7208da4946fca8c70392/src/components/diff/DiffWidget.tsx#L31-L35

Reproduce

1. Make changes to a file
2. Open a diff of that file
3. make more changes
4. try to update the diff without closing the diff tab.

Expected behavior

When clicking the Diff button the diff will be recomputed.

Two nice to have features would be:

1. Option to refresh the diff from a context menu when right clicking the diff widget
2. diffs that are visible are recomputed every so often, or whenever the diff is focused.

Context

• Python package version: 0.20.0rc0

• Extension version: 0.20.0-rc.0

Command Line Output

Paste the output from your command line running `jupyter lab` here, use `--debug` if possible.

Browser Output

Paste the output from your browser Javascript console here.

[jaipreet-s]

Agreed with @kgryte that this shouldn’t be configurable.

https://github.com/jupyterlab/jupyterlab-git/blob/8d56986409461cd9968d7208da4946fca8c70392/src/components/diff/DiffWidget.tsx#L31-L35

The intent of this line was to not open a new tab every-time the diff button is clicked. I do think we should retain that UX while addressing this to avoid an explosion of diff tabs.

Now, if a mainAreaItem with an id is found, We could address this in two ways to ensure the content gets updated with the latest diff.

1. Close that one and create a new one its place, rather than activating it, or
2. Just update the content of the mainAreaItem and then activate it.

P.S. Thanks for all the recent reports and PRs @ianhi !

[ianhi]

Don’t autoclose the diff, that’s too confusing. Just show some notification that the contents are the same (or whatever nbdime normally does on an empty diff)

👍

Another weird issue with the diff tabs is that if you have both an editor of the file and the diff open, then right click to close the diff tab the editor:

Turns out this is indeed a jupyterlab issue: https://github.com/jupyterlab/jupyterlab/issues/8509