TerminalView does not respect frame height on macOS Sonoma

[nkleemann]

As you can see from the screen recording, the LocalProcessTerminalView exceeds the frame height when it's displayed text exceeds the vertical height of the frame.

I'm targeting macOS Sonoma, using SwiftUI. I can also confirm that the same code worked an hour ago on macOS Ventura.

Small GIF showing the bug: Screen Recording

How I'm creating the View:

struct SuperColliderProcessView: NSViewRepresentable {
    
    @EnvironmentObject var superColliderProcessManager: SuperColliderProcessManager

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    func makeNSView(context: Context) -> LocalProcessTerminalView {
        let terminalView = LocalProcessTerminalView(frame: CGRect(x: 0, y: 0, width: 300, height: 90))        
        return terminalView
    }

    func updateNSView(_ nsView: LocalProcessTerminalView, context: Context) {}

    class Coordinator: NSObject {
        var parent: SuperColliderProcessView
        init(_ parent: SuperColliderProcessView) {
            self.parent = parent
        }
    }
}

// From SwiftUI

SuperColliderProcessView()
    // even with these two, on or the other - the terminalview doesnt respect the set height
    .frame(width: 300, height: 90)
    .frame(maxHeight: 90)

Edit:
Another angle on this bug:

Screen Recording

Maybe it's linked to some Scroll Behaviour changes in Sonoma?

[nkleemann]

@migueldeicaza I found the commit that introduces this Bug in Sonoma, its the deadlock fix here: e2c3749

Maybe a problem related to SwiftUI's drawing system, in relation to background threads?

Here is the self-contained example to recreate this bug. On macOS Sonoma, run this on any SwiftTerm version 1.2.2 and up:

import SwiftUI
import SwiftTerm

struct ContentView: View {
    
    @EnvironmentObject var replViewManager: REPLViewManager
    @State var redraw: Bool = false
    
    var body: some View {
        
        VStack {
            
            Text("VStack Top Text")
            
            REPLView()
                   
            Button {
                self.redraw.toggle()
                replViewManager.sendTextToREPL()
            } label: {
                Text("feed text to terminal")
            }
        }
        .padding()
    }
}

class REPLViewManager: ObservableObject {
    
    private var replView: LocalProcessTerminalView?
    
    func setupREPLView(_ view: LocalProcessTerminalView) {
        view.font = .monospacedSystemFont(ofSize: 10, weight: .regular)
        replView = view
        replView?.startProcess(executable: Constants.python3Path)
    }
    
    
    func sendTextToREPL() {
        guard let repl = replView else {
            print("REPLView is not initialized")
            return
        }
        
        repl.send(txt: Constants.blockContent)
    }
}

struct REPLView: NSViewRepresentable {
    
    @EnvironmentObject var replViewManager: REPLViewManager
    
    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    func makeNSView(context: Context) -> LocalProcessTerminalView {
        
        let view = LocalProcessTerminalView(frame: .init(x: 0, y: 0, width: 200, height: 200))
        
        replViewManager.setupREPLView(view)
        return view
    }

    func updateNSView(_ nsView: LocalProcessTerminalView, context: Context) {}
    
    class Coordinator: NSObject {
        var parent: REPLView

        init(_ parent: REPLView) {
            self.parent = parent
        }
    }
}

struct Constants {
    static let python3Path = "/usr/bin/python3"
    // dummy python code to send into repl
    static let blockContent = """
    import time

    def is_prime(n):
        if n <= 1:
            return False
        elif n <= 3:
            return True
        elif n % 2 == 0 or n % 3 == 0:
            return False
        i = 5
        while i * i <= n:
            if n % i == 0 or n % (i + 2) == 0:
                return False
            i += 6
        return True

    def print_first_n_primes(n):
        count = 0
        num = 2
        while count < n:
            if is_prime(num):
                print(num)
                count += 1
            num += 1

    start = time.time()
    print_first_n_primes(10000)
    end = time.time()
    print(f'Time taken: {end - start} seconds')
    """
}

@main
struct FreezingREPLApp: App {
    
    @StateObject var replViewManager = REPLViewManager()
    
    var body: some Scene {
        WindowGroup {
            ContentView()
                .environmentObject(replViewManager)
        }
    }
}

After clicking the button, the LocalProcessTerminalView expands out of the Frame given by SwiftUI:

[migueldeicaza]

Thank you for putting together a test case, I will investigate this weekend

[lkamil]

Any updates on this? I'm having the same issue

[nkleemann]

I fixed it with this PR, it's just a simple flag that needs to be set.