Runtime warning CLSUserDefaults is implemented twice

Question

I have seen a similar warning to that below for a pod-defined class when using #import syntax in cocoapod sources, but this is an internal apple class definition (CLSUserDefaults) which I have no control over and am not subclassing.

I don't know if this is really causing a problem, but it shouldn't be happening.

objc[22040]: Class CLSUserDefaults is implemented in both 
/System/Library/PrivateFrameworks/ClassKit.framework/Versions/A/ClassKit (0x7fff9932d2c0) and 

/Users/devusrid1/Library/Developer/Xcode/DerivedData/MyApp-cdokjmhxdrnhuodmhtibejxyqmqt/Build/Products/Debug/USR ID MyApp.app/Contents/MacOS/My App (0x10057f340). 

One of the two will be used. Which one is undefined.

I'm using Xcode 11

I also get this in Xcode Beta 5. – livingtech Aug 06 '19 at 20:07 — livingtech, Aug 06 '19 at 20:07

score 19 · Answer 1 · answered Aug 26 '19 at 04:19

19

Fabirc (or Crashlytics, depending on which versions used) defines a class named CLSUserDefaults.

It seems that ClassKit in iOS 13 also defines a CLSUserDefaults class, which leads to a name collision.

It should be fine as long as your app's code not using class CLSUserDefaults directly.

answered Aug 26 '19 at 04:19

Hvordan har du det

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But will it be fine for Crashlytics, I suppose they need to update their code? – Gerald Eersteling Sep 26 '19 at 12:41
First time I see a real world class name collision... I have wondered if Apple would ever add a class whose name clashes with my class-prefixes – eharo2 Oct 14 '19 at 18:14
Crashlytics has multiple classes with the CLS prefix (CLSAttributes, CSLLogging, CSLReport, etc). This could come up again in the future if a new class in ClassKit is added with any of these names – eharo2 Oct 15 '19 at 17:07
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This is causing my app to crash when ran on iOS 13, any solutions? – silly_cone Oct 16 '19 at 08:54
2

I am also running into the same issue and XCode will not start my app. I am on React Native version 59.9. XCode version 11.3 and IOS version 13.3. When I try to run the app through xocde this error comes up in the XCode console – Lucas Santos Jan 15 '20 at 17:47
I am also getting same issue. anyone find the solution? – Jignesh Kanani Jan 22 '20 at 13:11

score 3 · Answer 2 · answered Dec 18 '19 at 07:17

3

If you are you using Crashlytics, update your Fabric and Crashlytics versions in your Podfile as:

pod 'Fabric’, '~> 1.10.2’
pod 'Crashlytics’, '~> 3.14’

And then

pod install

answered Dec 18 '19 at 07:17

Sudheer Kumar Palchuri

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What if you are on a React Native version below 6? I am on 59.9 and Cocoa Pods are not available – Lucas Santos Jan 15 '20 at 17:46

Mahdi Moqadasi · Answer 3 · 2020-09-13T05:25:54.113

In my case same error showed (Just in iOS 13), but used another way to solve this:

I removed Fabric and Crashlytics from project (with uses in app)
Then error message changed! (There was two errors: One for RemoteNotification and one for using statusBar in AppDelegate)
I solved first using this: https://stackoverflow.com/a/45440917/5853262
Then solved second with commenting this line in AppDelegate: UIApplication.statusBarBackgroundColor = navigationBarColor
Then I reverted code to before doing step 1 using git(Before Removing Fabric and Crashlytics)
Then I fixed errors that not shown (Doing step 3 and 4)
After Clean and Build, the app launched successfully.

Notice: In your case maybe another error causes this problem, but when Fabric and Crashlytics exist, Xcode doesn't shows them. as I did, remove them, fix errors, then rollback changes and just fix bugs that you know. This would be work.

Runtime warning CLSUserDefaults is implemented twice

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