FirebaseApp.configure() triggers "Slow launches" warning on Xcode 16 / iOS 18

[alex-vasenin]

Description

I just switched to Xcode 16 and iOS 18 and running my app on the device started producing following runtime warnings on every app start:

/Pods/FirebaseCrashlytics/Crashlytics/Crashlytics/FIRCLSUserDefaults/FIRCLSUserDefaults.m:288 Performing I/O on the main thread can cause slow launches.
This is known to cause slow launches for your users.

/Users/alexvasenin/Documents/MeteorActive/Pods.nosync/FirebaseCore/FirebaseCore/Sources/FIRApp.m:348 Performing I/O on the main thread can cause slow launches.
This is known to cause slow launches for your users.

The first warning appears one time while the second one is repeated 6 times. All of the stack traces go through [FIRApp configure]. I did a quick test and indeed I found a call to FirebaseApp.configure() takes about 400-600ms on iPhone 15. However, I found if the debugger is NOT attached, the call takes only ~30ms, so it looks like the multiple stack unwinding takes the most time.

Having 7 runtime warnings without a good reason is bad. Please help to solve or silence this warnings.

Reproducing the issue

No response

Firebase SDK Version

10.2.0

Xcode Version

16.0

Installation Method

CocoaPods

Firebase Product(s)

Analytics, Crashlytics, Performance

Targeted Platforms

iOS

Relevant Log Output

No response

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[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[alex-vasenin]

[paulb777]

Do you see the same thing with more recent releases? 11.2.0 is the latest release.

[alex-vasenin]

My bad, I do actually use the latest release 11.2.0