Crashing on injecting to device about hotreloading HOT 21 CLOSED

It was probably fair enough as a security measure to make a blanket ban on the possibility of code modification on a device after review. The change was made in iOS 10. Device injection works as some other protections are relaxed provided you are debugging an app, see: https://github.com/johnno1962/InjectionScratch/blob/main/Sources/InjectionScratch/InjectionLoader.mm.

from hotreloading.

Hi, I know this sounds odd but try removing the super.viewDidLoad(). As I say, your millage is going to vary a lot more with the device version though the specific bit of code where it is crashing changed recently. Please try rolling back to version 4.6.0 (any minor version) and let me know how you get on.

from hotreloading.

Rolled back to 4.6.0, and it doesn't crash anymore, but doesn't behave as expected.
For example setting the colors in the injected method, makes it clear, regardless of what color I set.
The text value in the label does not change from the initial value at all.

from hotreloading.

Thanks I'll check out what's happened with 4.7.0+ There are lots of non-apparent limitations to the device injection. Re the colours thing: you should be able to use something like (objc_getClass("UIColor") as? UIColor.Type)?.red instead. The clear color is coming from messaging a nil class reference. Referring to classes (which is also part of messaging super) relies on a reference to a non-function symbol which is not a part of the current implementation though the message 🔥 ⚠️ Number of class refs 2 does not equal [] could be trying to tell us something related. I'll look into it. Anything else you find, let me know please.

from hotreloading.

Sure, thanks for looking into it.

from hotreloading.

I've updated the message above with a little more detail. What version of Xcode is this?

from hotreloading.

Getting the class and setting the color seems to work. However, I am unable to do anything to the label with a similar approach.

Xcode version: 14.0.1
Device version: 16.1

from hotreloading.

OK, I've pushed a few minor changes required by the 14.0 toolchain. Can you give them a try? There were a few minor issues with class references. To make it easier for you to pick up I've created a branch xcode-14.

from hotreloading.

It seems to be working, even without the objc_getClass method. The view background changes successfully. But I am unable to change any of the properties of the label which is added as a subview.

from hotreloading.

Great! Thanks for taking the time to raise the issue - this needed to be fixed. Can you show me some of the code you're trying to get working?

from hotreloading.

Same as my initial comment

import UIKit

class ViewController: UIViewController {
    let label = UILabel(frame: CGRect(x: 30, y: 200, width: 200, height: 150))

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .red
        view.addSubview(label)
        label.text = "hello"
        // Do any additional setup after loading the view.
    }
    
    
    @objc func injected() {
        view.backgroundColor = UIColor.yellow
        label.text = "anyoooo"
        label.backgroundColor = .red
        view.layoutIfNeeded()
    }
}

from hotreloading.

It seems something is still wrong with class references
I added another UIView, and tried to change its color, and resulted in a unrecognized selector for the color.

import UIKit

class ViewController: UIViewController {
    var label = UILabel(frame: CGRect(x: 30, y: 100, width: 200, height: 100))
    var tempView = UIView(frame: CGRect(x: 30, y: 300, width: 200, height: 100))

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .red
        label.backgroundColor = .orange
        tempView.backgroundColor = .blue
        view.addSubview(label)
        view.addSubview(tempView)
        label.text = "hello"
    }
    
    
    @objc func injected() {
        view.backgroundColor = .green
        label.text = "anyo"
        label.backgroundColor = .cyan
        tempView.backgroundColor = .yellow
    }
}

🔥 HotReloading connected /Users/denilct/Documents/Sharechat/HotReload/HotReload.xcodeproj
🔥 Watching files under the directory /Users/denilct/Documents/Sharechat/HotReload
🔥 💉 ⚠️ Your project file seems to be in the Desktop or Documents folder and may prevent InjectionIII working as it has special permissions.
🔥 Compiling /Users/denilct/Documents/Sharechat/HotReload/HotReload/ViewController.swift
🔥 Loaded .dylib - Ignore any duplicate class warning ⬆️
🔥 Interposed 2 function references.
🔥 Injected type #1 'HotReload.ViewController'
🔥 As class ViewController has an @objc injected() method, HotReloading will perform a "sweep" of live instances to determine which objects to message. If this fails, subscribe to the notification "INJECTION_BUNDLE_NOTIFICATION" instead.
🔥 (note: notification may not arrive on the main thread)
🔥 Starting sweep [HotReload.ViewController], []...
2022-10-31 13:49:42.854940-0400 HotReload[522:20005] +[UIView greenColor]: unrecognized selector sent to class 0x2167a0428
2022-10-31 13:49:42.855121-0400 HotReload[522:20005] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[UIView greenColor]: unrecognized selector sent to class 0x2167a0428'
*** First throw call stack:
(0x1c00c5e88 0x1b93fb8d8 0x1c023a784 0x1c00dbfa0 0x1c0144350 0x10bb070c4 0x10bb07270 0x104def710 0x104deb340 0x104ded1dc 0x104dee8dc 0x104deec60 0x104dee70c 0x104deed04 0x104ded280 0x104ded1a0 0x104dec578 0x104dec288 0x104deaa84 0x104ddf2ac 0x104da5fd8 0x104da5230 0x1053d05a8 0x1053d205c 0x1053e2810 0x1053e2354 0x1c01566f8 0x1c0138058 0x1c013ced4 0x1f943e368 0x1c261b3d0 0x1c261b034 0x1c8c0b308 0x104d95608 0x104d95590 0x104d9568c 0x1de7a4960)
libc++abi: terminating with uncaught exception of type NSException
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[UIView greenColor]: unrecognized selector sent to class 0x2167a0428'
terminating with uncaught exception of type NSException

from hotreloading.

My bad there, the fix for the class references problem has to be compiled into the app so I've rolled a new release https://github.com/johnno1962/InjectionIII/releases/tag/4.5.0RC6 which you should use. The problem with the initialised properties is a strange one. If you add the type as follows it works with the new 4.7.3 HotReloading.

     var label: UILabel! = UILabel(frame: CGRect(x: 30, y: 100, width: 200, height: 100))
     var tempView: UIView! = UIView(frame: CGRect(x: 30, y: 300, width: 200, height: 100))

Why this is and why the type has to be a force unwrap and why the problem is specific to devices I can't say I understand at this stage. I'll sleep on it but you should be able to make some more progress for now.

from hotreloading.

Yes, seems to be working with the force unwrap. As you said these might be the quirks of running it on device. Anyways, thanks for the quick help in solving this issue.

from hotreloading.

Yes, sometimes it takes a bit of imagination when you encounter a problem. I'm at sea as to why this is happening if I'm honest, the getter functions are returning nil. I'll have to wait for some random inspiration on how to fix this.

from hotreloading.

It seems when a real device is involved, everything goes haywire. I would love to help on this project, but have to read up on the black magic powering this entire system.

Feel free to close the issue if you like.

from hotreloading.

I'll leave the issue open for now as it would be nice to fix this particular issue. Device injection used to work fine then Apple made it so you couldn't dynamically load from a writable area on devices then much later I worked out how to simulate dynamic loading but the implementation is not complete which is where the problems come from. It works well enough particularly for SwiftUI that it might be useful for some but there can be seemingly random issues which can be difficult to debug. Note the note on p HotReloading.stack in the README for more complete stack traces.

from hotreloading.

Do you know when apple made that change? Would iOS 12 devices work better for this?

from hotreloading.

I've pushed version HotReloading 4.7.4 which should resolve this last problem you were seeing. It seems you can't inject getters/setters on a device. No need to update the app this time.

from hotreloading.

Yes, it is working without the force unwrap workaround.
Thank you for the quick fix.

from hotreloading.

Excellent!

from hotreloading.