[iOS26.1] Possible leak: Replacing tabs with identical identifier retains previous VC.

ViewController.swift

import UIKit
import SwiftUI

/// Minimal reproducible example for a potential memory leak when replacing `tabs` with
/// a new array that contains a tab with the same title/image/identifier.
///
/// Repro steps:
/// 1. Launch the app and open the Memory Graph (Product > Profile or Debug Memory Graph).
/// 2. This controller first sets `tabs` to contain ViewControllerA.
/// 3. It then immediately replaces `tabs` with a new array that contains ViewControllerB,
///    but with the SAME `title`, `image`, and `identifier` as the first tab.
/// 4. Observe in the memory graph: `TabItemViewControllerA` appears to be leaked (retained).
///
/// Expected:
/// - When replacing `tabs`, previously created view controllers should be released if they
///   are no longer referenced.
///
/// Actual:
/// - `TabItemViewControllerA` appears to remain in memory after `tabs` is replaced by a tab
///   with the same title/image/identifier.
final class ViewController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // MARK: 1) Set initial tab (A)
        // Intentionally using the same title and identifier for A and B to demonstrate the issue.
        let tabA = UITab(title: "TabA", image: nil, identifier: "a") { _ in
            let vc = TabItemViewControllerA()
            print("[Lifecycle] Creating TabItemViewControllerA: \(Unmanaged.passUnretained(vc).toOpaque())")
            return vc
        }
        tabs = [tabA]
        print("[Tabs] Set tabs = [A]")

        // MARK: 2) Replace with another tab (B) that has the SAME title/image/identifier
        // This mimics a real scenario where tabs might be rebuilt with identical identifiers.
        let tabB = UITab(title: "TabA", image: nil, identifier: "a") { _ in
            let vc = TabItemViewControllerB()
            print("[Lifecycle] Creating TabItemViewControllerB: \(Unmanaged.passUnretained(vc).toOpaque())")
            return vc
        }
        tabs = [tabB]
        print("[Tabs] Replaced tabs = [B] (same title/image/identifier as A)")

        // MARK: 3) Inspect memory graph
        // Open the Memory Graph now. `TabItemViewControllerA` may still be retained.
        print("[Repro] Now open Memory Graph to check if A is leaked/retained.")
    }
}

/// Simple VC types to distinguish instances in Memory Graph
final class TabItemViewControllerA: UIViewController {
    deinit {
        print("[Lifecycle] Deinit TabItemViewControllerA")
    }
}

final class TabItemViewControllerB: UIViewController {
    deinit {
        print("[Lifecycle] Deinit TabItemViewControllerB")
    }
}