Deprecate & remove DocumentManager "pathDeleted" event

[peterflynn]

• This has no usages in Brackets core code
• The preferred way to track deleted files is via FileSystem change events
• Because it's closely tied to the ProjectManager tree-updating code it will actually not fire in some cases where a file was deleted
• It's called twice whenever a file is deleted via the project tree UI (once when the UI updates itself synchronously, and again when ProjectManager's FS change listener sees the actual change on disk)

[dangoor]

reviewed medium priority to clean up for brackets 1.0 (we should deprecate sooner than that though)

[peterflynn]

Closing since #8751 is a superset of this

[le717]

Is this still a valid removal? From what I can tell, "pathDeleted" never even received a clear deprecation warning.

[dangoor]

You're right, the first step is deprecation and not removal. I think we should reopen this to do the deprecation and then remove it later. There are extensions listening for this message.

cc @JeffryBooher @peterflynn

[JeffryBooher]

We can't remove the event entirely but we can rename the event to make it private and deprecate the old event name.

The problem is that Pane objects can't just listen for FileSystem.change events and cleanup deleted files because there's no guaranteed order in which the handlers are called. Pane objects need to handle the FS event before DocumentManager does so it can clean and close up any editor view references. Otherwise, if DocumentManger handles the FS event before Pane objects do then it will complain about dangling references. That's why Pane objects listen to DocumentManger.pathDeleted events.