use notebook serializer for IW model

[amunger]

Use a file Provider for the interactive window so that the notebook serializer is used for the notebook model.
The IW file provider will drop any write operations and return an empty buffer for any read.
This way we will rely only on the backup provider to store the file data similar to an untitled file, but it won't request to save the file on close or appear dirty.

[mjbvz]

Overall the approach looks good to me but also run the FS changes by Ben to make sure this won't cause issues with editor state / backups

[rebornix]

The code looks good to me in overall. The only thing we want to double check how IW restore works with different settings (auto save on/off) as we are faking FS/dirty-state.

[bpasero]

I am not entirely sure why the no-op filesystem provider is needed to begin with, but instead of implementing this yourself, why not use the InMemoryFileSystemProvider we already have:

vscode/src/vs/platform/files/common/inMemoryFilesystemProvider.ts

Line 53 in d8568bb

export class InMemoryFileSystemProvider extends Disposable implements IFileSystemProviderWithFileReadWriteCapability {

[amunger]

I am not entirely sure why the no-op filesystem provider is needed to begin with, but instead of implementing this yourself, why not use the InMemoryFileSystemProvider we already have

There are write operations that occur for auto-save, so it just feels like we would be unnecessarily duplicating the memory usage since it's already stored in the back-up provider. On the other hand, that provider would likely be a better fit for the intended model, so I'm fine with using it if that extra memory usage isn't a concern.

[amunger]

After discussing with @bpasero, dropping all writes is preferrable to storing the data we don't actually need in an in-memory file provider

[bpasero]

That is a bit weird to have the ? even though you implement the method.

[bpasero]

Fyi you can remove the public keyword, this will make the method public by default.

[bpasero]

Maybe you can reduce the complexity of this class by extending the InMemoryFileSystemProvider and simply overriding the methods that write to the memory by skipping the write. This will make this a very slim class in the end.

[bpasero]

I left some comments how to further simplify this. I still do not understand why we need this, but I trust the judgment, since additional discussions seem to have happened.