Bug 173235 – WKNavigationAction.sourceFrame is not annotated as nullable, causing it to crash when accessed from Swift

• Component: WebKit API
• Status: NEW

[Matt Curtis]

Created attachment 312599 [details]
An Xcode Swift project demonstrating the issue.

Overview:

The WKNavigationAction.sourceFrame property is not annotated as nullable, causing it to crash when accessed from Swift. This bug shows up when making a navigation request that does not originate from the page itself using one of the WKWebView load methods. I've also filed this bug with Apple under rdar://32686815.

Steps to Reproduce:

This bug can be reproduced from both Objective-C and Swift but is more critical in Swift, as access of the property causes crashing:

1. Create a WKWebView and set its navigationDelegate to an object implementing the WKNavigationDelegate protocol method `webView(WKWebView, decidePolicyFor: WKNavigationAction, decisionHandler: (WKNavigationActionPolicy) -> Void)` insert `print(navigationAction.sourceFrame)` in its body.
2. Create a new navigation load request for the WKWebView using `webView.loadHTMLString(String)`
3. Run the project.

Actual Results:

The sourceFrame property is bridged as non-nullable, and upon access the application will crash.

Expected Results:

`nil` should be printed.

Build Date & Hardware: iOS 10, 9 & OSX 10.11 >.

[Radar WebKit Bug Importer]

<rdar://problem/32728039>