Allow scrapbook untitled working copies

[amunger]

required for #172974

We would like a IFileWorkingCopy implementation that is related to UntitledFileWorkingCopy as in, there is no file on disk backing the model so it wouldn't auto-save and would be recovered from a hot exit, but can more easily be discarded without prompting to save.

• If a user closes a window without onExitAndWindowClose hot exit enabled, the user would not be prompted to save
• The dirty indicator would not show for that file type

[bpasero]

@amunger I am trying to understand the requirements for such a change and maybe notebook team could help out. I see that backups are really tied to dirty state tracking, meaning that if a working copy does not report it is dirty, we do not create any backups. My hope would be to do a minimal change that does not disrupt how we manage backups...

So I am wondering if we can keep the dirty state of the working copy as it is today so that backups work, but see for certain UI locations where we show a dirty indicator today to hide it based on a new WorkingCopyCapability. We can expand on that strategy that to also hide any dialogs that would appear today when hot exit is off.

However, I miss a little bit the greater picture here for where else scrapbook working copies would have to alter its behaviour.

For my testing, I am running the command "New GitHub Issue Notebook" which normally opens an editor dirty, but with a few tweaks shows like a scrapbook. Contents restore after window reload too:

Dirty State in Editor
Changing this line to return false should remove the dirty indicator in the editor tab:

vscode/src/vs/workbench/contrib/notebook/common/notebookEditorInput.ts

Line 120 in 815295b

override isDirty() {

Dirty State for Working Copies
Changing this method to do an early return should remove the global dirty indicator:

vscode/src/vs/workbench/contrib/files/common/dirtyFilesIndicator.ts

Line 43 in 815295b

private onWorkingCopyDidChangeDirty(workingCopy: IWorkingCopy): void {

☝️ above are just hacks for now, but once we found all locations we can productise this further by checking for the working copy capability

[bpasero]

Ping

[amunger]

Sorry - I read through your comment too fast the first time and missed the ask.

Playing around with those two hacks seems to provide the behavior we're looking for except for the case of exiting with hotexit=off/onExit - Ideally we would not prompt to save the file in that case.