From d3bc4d5b82879ccb83483f99585127d981b43b38 Mon Sep 17 00:00:00 2001
From: Nathan Walker <walkerrunpdx@gmail.com>
Date: Sun, 30 May 2021 12:02:38 -0700
Subject: [PATCH] fix(core): guard unstable page/frame init contexts under
 async conditions (#9428)

---
 packages/core/ui/action-bar/index.ios.ts | 10 ++++++----
 packages/core/ui/frame/index.ios.ts      |  6 ++++--
 packages/core/ui/page/index.ios.ts       |  4 +++-
 3 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/packages/core/ui/action-bar/index.ios.ts b/packages/core/ui/action-bar/index.ios.ts
index 1deafaffe..6dc494478 100644
--- a/packages/core/ui/action-bar/index.ios.ts
+++ b/packages/core/ui/action-bar/index.ios.ts
@@ -353,6 +353,9 @@ export class ActionBar extends ActionBarBase {
 	}
 
 	private setColor(navBar: UINavigationBar, color?: Color) {
+		if (!navBar) {
+			return;
+		}
 		if (color) {
 			navBar.titleTextAttributes = <any>{
 				[NSForegroundColorAttributeName]: color.ios,
@@ -443,13 +446,12 @@ export class ActionBar extends ActionBarBase {
 	}
 
 	private get navBar(): UINavigationBar {
-		const page = this.page;
 		// Page should be attached to frame to update the action bar.
-		if (!page || !page.frame) {
+		if (this.page?.frame?.ios?.controller) {
+			return (<UINavigationController>this.page.frame.ios.controller).navigationBar;
+		} else {
 			return undefined;
 		}
-
-		return (<UINavigationController>page.frame.ios.controller).navigationBar;
 	}
 
 	[colorProperty.getDefault](): UIColor {
diff --git a/packages/core/ui/frame/index.ios.ts b/packages/core/ui/frame/index.ios.ts
index 856753b7a..bc8e93171 100644
--- a/packages/core/ui/frame/index.ios.ts
+++ b/packages/core/ui/frame/index.ios.ts
@@ -224,7 +224,7 @@ export class Frame extends FrameBase {
 			this._ios._disableNavBarAnimation = disableNavBarAnimationCache;
 		}
 
-		if (this._ios.controller.navigationBar) {
+		if (this._ios.controller?.navigationBar) {
 			this._ios.controller.navigationBar.userInteractionEnabled = this.navigationQueueIsEmpty();
 		}
 
@@ -666,7 +666,9 @@ class iOSFrame implements iOSFrameDefinition {
 	}
 	public set showNavigationBar(value: boolean) {
 		this._showNavigationBar = value;
-		this._controller.setNavigationBarHiddenAnimated(!value, !this._disableNavBarAnimation);
+		if (this._controller) {
+			this._controller.setNavigationBarHiddenAnimated(!value, !this._disableNavBarAnimation);
+		}
 	}
 
 	public get navBarVisibility(): 'auto' | 'never' | 'always' {
diff --git a/packages/core/ui/page/index.ios.ts b/packages/core/ui/page/index.ios.ts
index 68f0f9bcc..42e54f8cf 100644
--- a/packages/core/ui/page/index.ios.ts
+++ b/packages/core/ui/page/index.ios.ts
@@ -177,7 +177,9 @@ class UIViewControllerImpl extends UIViewController {
 			}
 
 			// If page was shown with custom animation - we need to set the navigationController.delegate to the animatedDelegate.
-			frame.ios.controller.delegate = this[DELEGATE];
+			if (frame.ios?.controller) {
+				frame.ios.controller.delegate = this[DELEGATE];
+			}
 
 			frame._processNavigationQueue(owner);