Thoughts?

Idk - It's the first time I hear about UntitledEditorInputFactoryFunction. Is the contract that it must be created with the final untitled URI or can the URI change later? In a way, I am wishing for generating the untitled-uri right before creating the model, like here. And only have the logic once, e.g not in mainThreadNotebook and the factory function.

I think this needs further clarification. Let's reserve some 1-1 time tomorrow or next week

@jrieken the factory was added only recently (last week?) to distinguish normal editors from untitled editors (and diff editors have their own factory too), but it doesn't really matter and is just there for convenience.

The underlying contract is that you get a lightweight "untyped" JSON editor input and have to return a heavy "typed" editor input that is then opened in an editor. There are only a few untyped editors:

• the 99% case: just a resource ({ resource: ...})
• the untitled case: most often {}, in some cases a resource is provided (only when e.g. run from command line with a path)
• the diff editor case: looks mostly like this: { originalInput: URI, modifiedInput: URI }

The URI of the editor input does not have to be known up front, in fact it is even optional for editor inputs so notebooks are free to do whatever they want, even if that means to resolve the URI only in the resolve method of the input.

1on1 sounds good, we can do next week since this probably is not making it for June anyway.

Btw I like the idea of having this logic somewhere here:

It would however require that for the aquire here:

We can pass on additional context to pipe through the untitled with associated file path case. Could be just a boolean too.

Continues in #130236, I can walk you through when you are back.