Pasting fails on High Sierra

[p0deje]

When trying to paste on High Sierra - nothing happens. It might the issue of focusing the application back.

[p0deje]

I nailed the issue down to enabling the sandbox 😞

It seems like sending a "CMD+V" event silently fails on High Sierra while succeeding in Catalina. What a mess.
I've submitted a report to Apple Developer asking if it's possible to deal with this somehow.

[p0deje]

FTR Pasting works fine on Mojave so it's only High Sierra issue.

[p0deje]

@adrianbj Could you try running this version of Maccy and let me know if it fixes the problem?

[p0deje]

Anyone else who's still running High Sierra and has similar issue is welcome to try ☝️ too!

[adrianbj]

I'm on vacation this week but will test next week. Thanks.

[p0deje]

The current implementation of pasting is as simple as "simulate CMD+V keyboard press":

  // Based on https://github.com/Clipy/Clipy/blob/develop/Clipy/Sources/Services/PasteService.swift.
  func paste() {
    guard accessibilityAllowed else {
      Maccy.returnFocusToPreviousApp = false
      // Show accessibility window async to allow menu to close.
      DispatchQueue.main.async(execute: showAccessibilityWindow)
      return
    }

    DispatchQueue.main.async {
      let vCode = UInt16(kVK_ANSI_V)
      let source = CGEventSource(stateID: .combinedSessionState)
      // Disable local keyboard events while pasting
      source?.setLocalEventsFilterDuringSuppressionState([.permitLocalMouseEvents, .permitSystemDefinedEvents],
                                                         state: .eventSuppressionStateSuppressionInterval)

      let keyVDown = CGEvent(keyboardEventSource: source, virtualKey: vCode, keyDown: true)
      let keyVUp = CGEvent(keyboardEventSource: source, virtualKey: vCode, keyDown: false)
      keyVDown?.flags = .maskCommand
      keyVUp?.flags = .maskCommand
      keyVDown?.post(tap: .cgAnnotatedSessionEventTap)
      keyVUp?.post(tap: .cgAnnotatedSessionEventTap)
    }
  }

Apple Developer support believes it's a bug that it does nothing in the sandboxed version of Maccy in High Sierra. Given it is okay in the newer macOS version - it won't be fixed.

As an alternative, I found an AppleScript that can simulate pasting (https://stackoverflow.com/questions/25747253/applescript-to-paste-clipboard):

tell application "System Events" to keystroke "v" using command down

It works in all OSes but suffers from the flaw that it also takes into account other pressed key modifiers. So, if someone pastes by pressing OPTION+5, it might fail if OPTION is not released yet - the app would receive CMD+OPTION+V which is wrong. There are various hacks that might improve this, but I'm not sure I want to go that route.

Another possible solution would be of course to simply disable the sandbox, but that has 2 problems:

1. Everybody who upgraded to the sandboxed version will lose their data as soon as a new non-sandboxed version is installed. Probably can be worked around with some migration script.
2. It renders my idea of distributing in the App Store impossible.

I'm going to give a shot and submit the app as-is to the App Store. It might still be blocked due to CGEvent and accessibility usage. If it happens, I'll see if the AppleScript-based version can pass the review. If yes, I'll do my best to hack around the key modifiers issue in AppleScript.

I'll revert to disabling sandbox if in the very end there will be no way to pass the App Store review. Though there are various clipboard managers out there that somehow work and passed the review, so I haven't lost the hope yet.

[p0deje]

Ok, the application has passed the review in the App Store. With that said, I lean towards the easiest route which is to drop support for High Sierra at all. One can still keep using the old version that works without a sandbox (v0.14.1).

if anyone can come up with a different solution where I can work it around in High Sierra, I'll be happy to bring support back. I understand how disappointed High Sierra users might be and I'd love to make it work, but I just don't see a way.

[adrianbj]

@p0deje - I guess there really isn't much point me testing now. I would upgrade from High Sierra, but it's not important enough for me to bother with the possible issues on my 2011 MBP - happy to just keep it ticking along for a while longer 👍

Thanks for your efforts though. For now, I've gone back to Clipy.

[mul14]

@adrianbj Could you try running this version of Maccy and let me know if it fixes the problem?

I still use High Sierra. That version working properly for me.

[adrianbj]

@mul14 - that version does seem to work as expected - thanks! Is this a version you modified yourself?

[mul14]

@adrianbj I don't modify anything. Just download from here and use it.