Parse & Xcode 6.4 problems unwrapping optionals with Swift 1.2 - swift

Question

I'm having trouble unwrapping an optional after upgrading to xcode 6.4. Here's the error I'm getting when running this line of code:
query.whereKey("follower", equalTo: PFUser.currentUser()!.objectId!)
fatal error: unexpectedly found nil while unwrapping an Optional value
(lldb)
I know that with the new update for xcode you have to be more careful unwrapping optionals, but I'm not sure what changes I need to make to make swift cooperate. I've tried many different ways that were suggested on S/O but haven't gotten one to work yet. Here's my full code:
Thanks!!
import UIKit
import Parse
class TableViewController: UITableViewController {
var usernames = [""]
var userids = [""]
var isFollowing = ["":false]
override func viewDidLoad() {
super.viewDidLoad()
var query = PFUser.query()
query?.findObjectsInBackgroundWithBlock({ (objects, error) -> Void in
if let users = objects {
self.usernames.removeAll(keepCapacity: true)
self.userids.removeAll(keepCapacity: true)
self.isFollowing.removeAll(keepCapacity: true)
for object in users {
if let user = object as? PFUser {
if user.objectId! != PFUser.currentUser()?.objectId {
self.usernames.append(user.username!)
self.userids.append(user.objectId!)
var query = PFQuery(className: "followers")
***query.whereKey("follower", equalTo: PFUser.currentUser()!.objectId!)***
query.whereKey("following", equalTo: user.objectId!)
query.findObjectsInBackgroundWithBlock({ (objects, error) -> Void in
if let objects = objects {
if objects.count > 0 {
self.isFollowing[user.objectId!] = true
} else {
self.isFollowing[user.objectId!] = false
}
}
if self.isFollowing.count == self.usernames.count {
self.tableView.reloadData()
}
})
}
}
}
}
})
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Potentially incomplete method implementation.
// Return the number of sections.
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete method implementation.
// Return the number of rows in the section.
return usernames.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! UITableViewCell
cell.textLabel?.text = usernames[indexPath.row]
let followedObjectId = userids[indexPath.row]
if isFollowing[followedObjectId] == true {
cell.accessoryType = UITableViewCellAccessoryType.Checkmark
}
return cell
}
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
var cell:UITableViewCell = tableView.cellForRowAtIndexPath(indexPath)!
let followedObjectId = userids[indexPath.row]
if isFollowing[followedObjectId] == false {
isFollowing[followedObjectId] = true
cell.accessoryType = UITableViewCellAccessoryType.Checkmark
var following = PFObject(className: "followers")
following["following"] = userids[indexPath.row]
following["follower"] = PFUser.currentUser()?.objectId
following.saveInBackground()
} else {
isFollowing[followedObjectId] = false
cell.accessoryType = UITableViewCellAccessoryType.None
var query = PFQuery(className: "followers")
query.whereKey("follower", equalTo: PFUser.currentUser()!.objectId!)
query.whereKey("following", equalTo: userids[indexPath.row])
query.findObjectsInBackgroundWithBlock({ (objects, error) -> Void in
if let objects = objects {
for object in objects {
object.deleteInBackground()
}
}
})
}
}
}

Answer 1

You can make use of Optional Binding to access the logged in user to make sure that it is not nil before using it as a query parameter.
So you should change the line:
query.whereKey("follower", equalTo: PFUser.currentUser()!.objectId!)
With:
if let userObj = PFUser.currentUser()?.objectId {
query.whereKey("follower", equalTo: userObj)
}
Now this will solve your bug and prevent your app from crashing, but maybe you should restructure your app in a way to confirm that the user has logged in no matter what when reaching this UITableViewController.
In any case you should still use Optional Binding to prevent a potential crash.