iOS app in a zombified state

Question

iOS app 1.4.3, iOS 9.2.1

While viewing a post, the app somehow ended up in a state where it refuses to do much of anything.

What does work:

• Swipe-scrolling vertically
• Jumping to the previous / next post using the up / down buttons

Everything else, though, has no effect:

• Swipe-scrolling horizontally will not return to the previous view
• Tapping on a code block will not zoom to code-block view
• Tapping Delete button to delete a post will show a confirmation dialog, but saying yes will not cause deletion
• The Add Comment button brings up the text field, but I cannot type anything in it; I can only dismiss it
• None of the other buttons (Share, More, etc.) do anything
• Cannot view user profiles or revision history
• Tapping on links in a post or comment will not show a web page
• Tapping on a tag shows some visual feedback with a temporary color change, but doesn't do anything else

I still receive push notifications, but tapping on them doesn't take me anywhere.

Answer 1

This will be fixed in 1.4.4.1, shipping early March.

It appears the SFSafariViewController swipe gesture in 9.2 breaks the view transitioning state. This should also be fixed in 9.3.

I'll also be applying this fix from the Apple forums for users still on 9.2:

SFSafariViewController *viewController = [[SFSafariViewController alloc] initWithURL:URL];
viewController.delegate = (id)delegate;

// There was a major bug in 9.2 where SFSafariViewController's swipe gesture broke the view controller hierarchy.
// This fix comes from https://forums.developer.apple.com/thread/29048#discussion-105377
if (SEIsAtLeastIOSVersion(9, 2) && !SEIsAtLeastIOSVersion(9, 3)) {
    viewController.modalPresentationStyle = UIModalPresentationOverFullScreen;
    UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:viewController];
    navigationController.navigationBarHidden = YES;
    return navigationController;
} else {
    return viewController;
}

Answer 2

Apologies for posting an answer but I don't have enough rep to post a comment.

The action that causes this behavior is a swipe in from the left to return to a question after following a link that opens the in-app browser.

Hope it helps!