autosavedContentsFileURL is nil after successful autosaveWithDelegate

Question

I am having a heck of a time getting NSDocument's autosave to work.

I have a NSDocument subclass that takes some user input and computes (generates) a coverTree for that data. Upon completion, I am attempting to autosave the document to capture both the user inputs and resulting tree. I am trying to use debugging to locate if/where an autosave occured.

The following code snippet is from my view controller

  @IBAction func handleGenerate(_ sender: NSButton)
  {
    ...

    // do the work

    document.coverTree.generate(dataSet:data, source:dataSourceFinal.stringValue)
    document.updateChangeCount(.changeDone)
    document.autosave(withDelegate: self, didAutosave: #selector(handleDidAutosave(document:didAutosaveSuccessfully:contextInfo:)), contextInfo: nil)
  }

  func handleDidAutosave(document:NSDocument, didAutosaveSuccessfully:Bool, contextInfo:UnsafeMutableRawPointer)
  {
    print("VC::Did Autosave(document:\(document), didAutosaveSuccessfully:\(didAutosaveSuccessfully))")
    print("VC::InPlace: \(Document.autosavesInPlace())")
    print("VC::Autosaved at: \(document.autosavedContentsFileURL)")
  }

As shown above, I provided a completion handler for the purpose of debugging. Here is what I am seeing in the console:

Document::updateChangeCount
VC::Did Autosave(document:<coverTreeDemo.Document: 0x6180000cd3c0>, didAutosaveSuccessfully:true) 
VC::InPlace: true 
VC::Autosaved at: nil

The completion handler was told autosave was successful (didAutosaveSucessfully was set to true), but the location of the autosave is nil. I looked in ~/Library/Autosave Information and there is nothing there that I can find for my application (or Xcode).

I also have each of the write... methods on my document class instrumented to print to the console when invoked. I am not seeing any output from these.

So why could it be that the autosave completion handler is told the save was successful when it appears nothing was written out?

Note that I can successfully save the document through the File>Save menu (and load it back up with File>Open). The windows/documents also restore correctly on start up IFF I saved them through the File>Save menu. It is only autosave that I'm having issues with.

Thanks much, mike

Answer 1

Simple solution is to stop making stupid mistakes...

In instrumenting my code for debugging purposes, I overrode updateChangeCount to print out a message (to show that it was, in fact being called).

I forgot to invoke super.updateChangeCount. The document was never marked as dirty and therefor never autosaved.

doh!