[iOS] FireStore keep on using CPU

[shohe]

Description

I'm using FireStore at my current iOS project and I realized that when generate CollectionReference or DocumentReference, FireStore starts keep on using CPU (around 10%) until app close.

I'm using

• Firebase 9.5.0
• install with SwiftPackageManager
• Xcode version 13.4.1 (13F100)

Here is sample code (same as document).

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
    FirebaseApp.configure()
    let db = Firestore.firestore()
    db.collection("Collection").document("test").setData(["lastLoginAt":Date()], merge: true)

    // Even this code happens issue ↓
    // let ref = db.collection("Collection")

    return true
}

Reproducing the issue

No response

Firebase SDK Version

9.5.0

Xcode Version

13.4.1

Installation Method

Swift Package Manager

Firebase Product(s)

Firestore

Targeted Platforms

iOS

[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.

[dconeybe]

This is actually an issue that we (the Firestore SDK developers) just discovered today. The bug was added in 9.5.0. There is no workaround, except downgrading. The fix will almost certainly be in the next release, which is scheduled for mid-September 2022. Here is the fix: #10170.

[dconeybe]

FYI Firebase 9.6.0 is now released with the fix.

https://firebase.google.com/support/release-notes/ios#version_960_-_september_13_2022