Your SwiftUI app crashes in *** Assertion failure in -[NSTouchBarLayout setLeadingWidgetWidth:], NSTouchBarLayout.m:78 ? Use this hack to work around the problem!

TouchBarSwiftUIHack.swift

import Foundation
import InterposeKit
import OSLog

/// Hack tow work around Assertion failure in -[NSTouchBarLayout setLeadingWidgetWidth:], NSTouchBarLayout.m:78
/// This sometimes happens when macOS restores a window.
/// This even runs if there is no OS-level touch bar.
class MacOSWorkarounds {
    static let logger = Logger(category: "MacOSWorkarounds")

    static let installMacTouchBarHack: Void = {
        do {
            guard let klass = NSClassFromString("NSTouchBarLayout") else { return }
            _ = try Interpose(klass) { builder in
                try builder.hook("setLeadingWidgetWidth:",
                                 methodSignature: (@convention(c) (AnyObject, Selector, CGFloat) -> Void).self,
                                 hookSignature: (@convention(block) (AnyObject, CGFloat) -> Void).self) { store in { innerSelf, width in
                    var newWidth = width
                    if width < 0 {
                        logger.warning("Applying workaround for NSTouchBarLayout crash.")
                        newWidth = 0
                    }
                    store.original(innerSelf, store.selector, newWidth)
                }}}
        } catch {
            logger.error("Failed to install workaround for touch bar crash: \(String(describing: error)).")
        }
    }()
}

Thanks for this, was going slightly bonkers over this crash.