Q:

UILongPressGestureRecognizer breaks tableView scrolling

I created a custom Label class that contains a UILongPressGestureRecognizer, and I am invoking it in tableview cells in a TableViewController. The long press gesture recognizer works (two clickable zones in an attributed sting), but the tableView containing the labels no longer scrolls (pans) if the scroll gesture begins in one of the UILongPressGestureRecognizer zones of my CustomLabel. I have tried cancelsTouchesInView = false as well as the various responses below, to no avail. Any suggestions would be greatly appreciated. I've spent a week on this problem. My code is below.
Here is the CustomLabel class:
class CustomLabel: UILabel {

    let layoutManager = NSLayoutManager()
    let textContainer = NSTextContainer(size: CGSize.zero)
    var textStorage = NSTextStorage() {
        didSet {
            textStorage.addLayoutManager(layoutManager)
        }
    }

    var onCharacterTapped: ((_ label: UILabel, _ characterIndex: Int, _ state: Bool) -> Void)?

    let tapGesture = UILongPressGestureRecognizer()

    override var attributedText: NSAttributedString? {
        didSet {
            if let attributedText = attributedText {

                if attributedText.string != textStorage.string {

                textStorage = NSTextStorage(attributedString: attributedText)

                DispatchQueue.main.async {

                    let characterDelay = TimeInterval(0.01 + Float(arc4random()) /  Float(UInt32.max)) / 100

                    for (index, char) in attributedText.string.characters.enumerated() {

                        DispatchQueue.main.asyncAfter(deadline: .now() + characterDelay * Double(index)) {
                            print("character ch is: \(char) at index: \(index)")
                            super.attributedText = attributedText.attributedSubstring(from: NSRange(location: 0, length: index+1))
                        }
                    }
                }
                }

            } else {
                textStorage = NSTextStorage()
            }
        }
    }

    override var lineBreakMode: NSLineBreakMode {
        didSet {
            textContainer.lineBreakMode = lineBreakMode
        }
    }

    override var numberOfLines: Int {
        didSet {
            textContainer.maximumNumberOfLines = numberOfLines
        }
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setUp()
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        setUp()
    }

    func setUp() {
        isUserInteractionEnabled = true
        layoutManager.addTextContainer(textContainer)
        textContainer.lineFragmentPadding = 0
        textContainer.lineBreakMode = lineBreakMode
        textContainer.maximumNumberOfLines = numberOfLines
        tapGesture.addTarget(self, action: #selector(CustomLabel.labelTapped(_:)))
        tapGesture.minimumPressDuration = 0
        tapGesture.cancelsTouchesInView = false
        //tapGesture.delegate = self.superview
        addGestureRecognizer(tapGesture)
    }

    override func layoutSubviews() {
        super.layoutSubviews()
        textContainer.size = bounds.size
    }

    func labelTapped(_ gesture: UILongPressGestureRecognizer) {

        let locationOfTouch = gesture.location(in: gesture.view)
        let textBoundingBox = layoutManager.usedRect(for: textContainer)
        let textContainerOffset = CGPoint(x: (bounds.width - textBoundingBox.width) / 2 - textBoundingBox.minX, y: (bounds.height - textBoundingBox.height) / 2 - textBoundingBox.minY)
        let locationOfTouchInTextContainer = CGPoint(x: locationOfTouch.x - textContainerOffset.x, y: locationOfTouch.y - textContainerOffset.y)
        let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)

        if gesture.state == .began {

            onCharacterTapped?(self, indexOfCharacter, true)

        } else if gesture.state == .ended {

            onCharacterTapped?(self, indexOfCharacter, false)

        }

    }

}

Here is the cellClass:
class friendTextCell: UITableViewCell {

    @IBOutlet weak var labelText: CustomLabel!

    override func awakeFromNib() {
        super.awakeFromNib()
        self.layoutIfNeeded()
    }

}

And here is selections from the TableViewControllerClass where CustomCells are created:
class UsersViewController: UITableViewController, UIGestureRecognizerDelegate {

private func gestureRecognizer(gestureRecognizer: UIPanGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UILongPressGestureRecognizer) -> Bool {return true}

    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer) -> Bool {
        return gestureRecognizer === longPressRecognizer &&
            (otherGestureRecognizer.view?.isDescendant(of:tableView) ?? false)
    }

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "friendText", for: indexPath) as! friendTextCell

        print("keyArrrrray is: \(keyArray)")

        if indexPath.section == 0 && indexPath.row < keyArray.count {
            self.removeInstructions()
            cell.labelText.font = cell.labelText.font.withSize(17)
            let text = "> "+namesArray[indexPath.row] + ": " + linkArray[indexPath.row]
            let name = namesArray[indexPath.row]
            let link = linkArray[indexPath.row]
            let imageLink = imageURLArray[indexPath.row]
            let nameChCount = name.characters.count
            let linkChCount = link.characters.count

            let attributedString = NSMutableAttributedString(string: name + ": " + link, attributes: nil)

            let totalChCount = attributedString.string.characters.count

            let linkRange = NSMakeRange(0, nameChCount) // for the word "link" in the string above

            let linkAttributes: [String : AnyObject] = [
                NSForegroundColorAttributeName : UIColor.white, NSUnderlineStyleAttributeName : NSUnderlineStyle.styleSingle.rawValue as AnyObject]
            attributedString.setAttributes(linkAttributes, range:linkRange)

            cell.labelText.attributedText = attributedString

            cell.labelText.onCharacterTapped = { label, characterIndex, state in

                let highlight: [String : AnyObject] = [NSForegroundColorAttributeName : UIColor.black, NSBackgroundColorAttributeName : UIColor.white]

                if state == true {
                    if characterIndex < nameChCount {
                        print("name press began at character \(characterIndex)")
                        attributedString.addAttributes(highlight, range:NSMakeRange(0, nameChCount))
                        cell.labelText.attributedText = attributedString
                    } else if characterIndex > nameChCount {
                        print("link press began at character \(characterIndex)")
                        let startPos = nameChCount + 2
                        let endPos = totalChCount-nameChCount-2
                        attributedString.addAttributes(highlight, range:NSMakeRange(startPos, endPos))
                        cell.labelText.attributedText = attributedString
                    }

                } else if state == false {

                    if characterIndex < name.characters.count {

                        if let userVC:UserViewTableViewController = self.storyboard?.instantiateViewController(withIdentifier: "UserVC") as? UserViewTableViewController {
                            userVC.userName = name
                            userVC.shareLink = link
                            userVC.imageLink = imageLink
                            self.navigationController?.pushViewController(userVC, animated: true)
                        }

                }

                if characterIndex > name.characters.count && characterIndex <= link.characters.count + name.characters.count {

                    //extract link from array
                    let link = self.linkArray[indexPath.row]
                    print("on click link is: \(link)")

                    //Present SafariViewController with link
                    let svc = SFSafariViewController(url: NSURL(string: link)! as URL)
                    self.present(svc, animated: true, completion: nil)

                }
                }

            }

        } else if keyArray.isEmpty && indexPath.section == 0 {

            cell.labelText.text = "..."

        }

        if indexPath.section == 1 && keyArray.count <= 1 {
            let message = "> Press the + button to add more friends."
            cell.labelText.animate(newText: message, characterDelay: TimeInterval(0.01 + Float(arc4random()) /  Float(UInt32.max)) / 200)
        } else if indexPath.section == 1 {
            cell.labelText.text = ""
        }

        return cell

    }

A:

tableView containing the labels no longer scrolls (pans) if the scroll gesture begins in one of the UILongPressGestureRecognizer 

This problem occurs when you set the UILongPressGestureRecognizer's minimum press duration to 0 and it starts to grab the scroll view's embedded gesture recognizer. You can resolve it by using bigger delay, if you need to use long press gesture recognizer with delay, how it's supposed to be.
First will respond your table view's didSelectRow at and after delay your selector.
It worked for me, although i removed tapGesture.cancelsTouchesInView = false and added attribute @objc before declaring your selector method for recognizer (requires if you write in swift 4).
If you want to use UILongPressGestureRecognizer with no delay, just use UITapGestureRecognizer. In this case table view will scroll, but you can't receive didSelectRow method if you tap on the label.
Table and Collection views gestures delegates are set to underlying scroll view so you cant use UIGestureRecognizerDelegate methods on your UIViewController for that purpose. 
If you want to receive some kind of callback in you View Controller when that recognizer fires, you can throw call back by implementing delegate methods. 
Create CustomLabel's delegate that implements labelTapped function for example. In your selector call that delegate function. Make your cell conform to that delegate and repeat that in your cell to throw function to your UIViewController. Also you can use closure delegate pattern.
Hope that helps.
Update
So the solution is to make UILongPressGestureRecognizer 's minimumPressDuration to 0 as you initially did and assign the delegate to it's cell (superview in my case). 
In cell you need to override this method:
gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
    return gestureRecognizer == yourGesture || otherGestureRecognizer == yourGesture
}

By the way you don't need to make your cell conform to UIGestureRecognizerDelegate as it already does

