Don't hold the delegate when UIKit refuses to show the Customer Center

Sources/SuperwallKit/CustomerCenter/CustomerCenterManager.swift

@@ -137,10 +137,20 @@ final class CustomerCenterManager {
       self?.retainedDelegate = nil
       onDismiss?()
     }
+    presenting.present(controller, animated: presentsAnimated)
+    // UIKit refuses some presentations (the presenter isn't in a window, or is mid-transition)
+    // and only logs it, so check that it took the controller before holding on to anything.
+    if controller.presentingViewController == nil {
+      Logger.debug(
+        logLevel: .error,
+        scope: .customerCenter,
+        message: "The Customer Center couldn't be presented from \(type(of: presenting))."
+      )
+      return
+    }
     retainedDelegate = delegate
     presentedController = controller
     presentCount += 1
-    presenting.present(controller, animated: presentsAnimated)
   }
 
   /// Dismisses the presented Customer Center, if any.

Sources/SuperwallKit/CustomerCenter/UIKit/CustomerCenterViewController.swift

@@ -47,8 +47,9 @@ public final class CustomerCenterViewController: UIHostingController<CustomerCen
   /// ``isLeavingHierarchy``.
   ///
   /// Internal rather than private only so tests can set it: a hostless test target never drives a
-  /// modal transition to completion, so UIKit never populates `presentingViewController` there and
-  /// this can't be reached through a real presentation.
+  /// modal transition to completion, so `viewDidAppear` never runs there and this can't be set
+  /// through a real presentation. UIKit does still set `presentingViewController` as soon as the
+  /// presentation starts.
   var wasPresentedModally = false
 
   /// Latches ``deliverDismissal()``; see its note on the overlapping call sites.

Tests/SuperwallKitTests/CustomerCenter/CustomerCenterManagerTests.swift

@@ -84,6 +84,48 @@ struct CustomerCenterManagerTests {
     window.isHidden = true
   }
 
+  @Test("a presentation UIKit refuses doesn't keep the delegate, and the next present works")
+  func refusedPresentationReleasesDelegate() {
+    final class ProbeDelegate: CustomerCenterDelegate {}
+
+    let container = DependencyContainer()
+    let manager = CustomerCenterManager(container: container)
+    manager.presentsAnimated = false
+    // Its view isn't in a window, so UIKit refuses to present from it.
+    let detachedPresenter = UIViewController()
+
+    var strongDelegate: ProbeDelegate? = ProbeDelegate()
+    weak var weakDelegate = strongDelegate
+    var dismissCount = 0
+
+    manager.present(
+      configuration: nil,
+      from: detachedPresenter,
+      delegate: strongDelegate,
+      onDismiss: { dismissCount += 1 }
+    )
+    strongDelegate = nil
+    spinRunLoop(timeout: 1) { weakDelegate == nil }
+
+    #expect(detachedPresenter.presentedViewController == nil)
+    #expect(!manager.isPresented)
+    #expect(manager.presentCount == 0)
+    #expect(weakDelegate == nil)
+    // Nothing was shown, so nothing was dismissed.
+    #expect(dismissCount == 0)
+
+    let presenter = UIViewController()
+    let window = makeTestWindow(rootViewController: presenter)
+    window.makeKeyAndVisible()
+    spinRunLoop(timeout: 1) { presenter.viewIfLoaded?.window != nil }
+
+    manager.present(configuration: nil, from: presenter, delegate: nil, onDismiss: nil)
+    #expect(manager.isPresented)
+    #expect(manager.presentCount == 1)
+
+    window.isHidden = true
+  }
+
   @Test("viewDidDisappear fires didDismiss while the delegate is still retained")
   func viewDidDisappearFiresDelegateBeforeRelease() {
     final class ProbeDelegate: CustomerCenterDelegate {