[FirebaseDatabase] Databases are disconnected temporarily on app goes inactive state.

[Kurogoma4D]

Description

Since v10.27.0, FirebaseDatabase now temporarily goes offline when the app is in the inactive state (e.g., when control center is opened, when returning to the home screen, etc.) and comes back online after a while.

In v10.26.0, the behavior was below:

but is in v10.27.0 or later:

Reproducing the issue

1. Create iOS App project
2. Integrate Firebase project and add FirebaseDatabase package
3. Replace App code with like this:

import SwiftUI
import UIKit
import FirebaseCore
import FirebaseDatabase

@main
struct RtdbReproIOSApp: App {
    
    @UIApplicationDelegateAdaptor (AppDelegate.self) var appDelegate
    
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

class AppDelegate: NSObject, UIApplicationDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
        FirebaseApp.configure()
        
        let connectedRef = Database.database().reference(withPath: ".info/connected")
        connectedRef.observe(.value, with: { snapshot in
          if snapshot.value as? Bool ?? false {
            print("Connected")
          } else {
            print("Not connected")
          }
        })
        
        return true
    }
}

Firebase SDK Version

10.27.0

Xcode Version

15.3

Installation Method

Swift Package Manager

Firebase Product(s)

Database

Targeted Platforms

iOS

Relevant Log Output

No response

If using Swift Package Manager, the project's Package.resolved

Expand Package.resolved snippet

{
  "originHash" : "c63c63846d9c539229e96de38d6af51417e28c0ee9a0bc48bd0f0f19d923c329",
  "pins" : [
    {
      "identity" : "abseil-cpp-binary",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/abseil-cpp-binary.git",
      "state" : {
        "revision" : "194a6706acbd25e4ef639bcaddea16e8758a3e27",
        "version" : "1.2024011602.0"
      }
    },
    {
      "identity" : "app-check",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/app-check.git",
      "state" : {
        "revision" : "3b62f154d00019ae29a71e9738800bb6f18b236d",
        "version" : "10.19.2"
      }
    },
    {
      "identity" : "firebase-ios-sdk",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/firebase/firebase-ios-sdk",
      "state" : {
        "revision" : "8bcaf973b1d84e119b7c7c119abad72ed460979f",
        "version" : "10.27.0"
      }
    },
    {
      "identity" : "googleappmeasurement",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/GoogleAppMeasurement.git",
      "state" : {
        "revision" : "70df02431e216bed98dd461e0c4665889245ba70",
        "version" : "10.27.0"
      }
    },
    {
      "identity" : "googledatatransport",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/GoogleDataTransport.git",
      "state" : {
        "revision" : "a637d318ae7ae246b02d7305121275bc75ed5565",
        "version" : "9.4.0"
      }
    },
    {
      "identity" : "googleutilities",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/GoogleUtilities.git",
      "state" : {
        "revision" : "57a1d307f42df690fdef2637f3e5b776da02aad6",
        "version" : "7.13.3"
      }
    },
    {
      "identity" : "grpc-binary",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/grpc-binary.git",
      "state" : {
        "revision" : "e9fad491d0673bdda7063a0341fb6b47a30c5359",
        "version" : "1.62.2"
      }
    },
    {
      "identity" : "gtm-session-fetcher",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/gtm-session-fetcher.git",
      "state" : {
        "revision" : "a2ab612cb980066ee56d90d60d8462992c07f24b",
        "version" : "3.5.0"
      }
    },
    {
      "identity" : "interop-ios-for-google-sdks",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/interop-ios-for-google-sdks.git",
      "state" : {
        "revision" : "2d12673670417654f08f5f90fdd62926dc3a2648",
        "version" : "100.0.0"
      }
    },
    {
      "identity" : "leveldb",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/firebase/leveldb.git",
      "state" : {
        "revision" : "a0bc79961d7be727d258d33d5a6b2f1023270ba1",
        "version" : "1.22.5"
      }
    },
    {
      "identity" : "nanopb",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/firebase/nanopb.git",
      "state" : {
        "revision" : "b7e1104502eca3a213b46303391ca4d3bc8ddec1",
        "version" : "2.30910.0"
      }
    },
    {
      "identity" : "promises",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/google/promises.git",
      "state" : {
        "revision" : "540318ecedd63d883069ae7f1ed811a2df00b6ac",
        "version" : "2.4.0"
      }
    },
    {
      "identity" : "swift-protobuf",
      "kind" : "remoteSourceControl",
      "location" : "https://github.com/apple/swift-protobuf.git",
      "state" : {
        "revision" : "e17d61f26df0f0e06f58f6977ba05a097a720106",
        "version" : "1.27.1"
      }
    }
  ],
  "version" : 3
}

If using CocoaPods, the project's Podfile.lock

Expand Podfile.lock snippet

Replace this line with the contents of your Podfile.lock!

[rizafran]

Thanks for reporting this, @Kurogoma4D. I was able to reproduce the issue. I'll raise this to our engineers and see what we can do here.