Bug 185257 – A WKWebView in a UIViewController that is presented modally and uses a file picker will be incorrectly dismissed by the system

• Component: New Bugs
• Status: RESOLVED FIXED

[Zach Waugh]

Created attachment 339421 [details]
Sample project that reproduces the bug

This is similar to https://bugs.webkit.org/show_bug.cgi?id=165225. When a WKWebView is presented in a modal UIViewControlller and a file picker is displayed (from <input type="file">), taking any actions from within the file browser will result in the file browser modal being dismissed as well as the application modal. The expected result is only the file browser modal is dismissed and the application modal remains.

To Reproduce:
1. Present a UIViewController containing a WKWebView modally
2. The WKWebView should have an <input type="file"> element.
3. Click the "Choose File" button
4. Choose "Browse" from the action sheet that is displayed
5. iOS will present the file browser modally
6. When the file browser modal is displayed, either choose "Cancel" in the top-right or select a file
7. Upon either of those actions, the file browser modal will be dismissed as well as this application modal that contains the web view
8. The expected behavior is only the file browser modal is dismissed and the application modal remains

I've attached a sample project that reproduces this in iOS 11.3, which is also available on GitHub here with an example GIF: https://github.com/zachwaugh/wkwebview-bugs/tree/master/ModalFileDismissal

[Radar WebKit Bug Importer]

<rdar://problem/40819252>

[Tim Horton]

*** This bug has been marked as a duplicate of bug 183549 ***

[Zach Waugh]

I can't see the full details of the linked bug, but I don't believe they are the same issue. This bug report is concerning when the UIDocumentBrowserViewController is presented and subsequently dismissed. If you click through to this link (https://github.com/zachwaugh/wkwebview-bugs/tree/master/ModalFileDismissal), there is gif showing the full bug and it's unrelated to the action sheet.

I've confirmed the bug is still present in iOS 12 beta 1 building against Xcode 10 beta 1.

[Tim Horton]

Interesting! I bet it has a similar fix, then.

[Tim Horton]

It does look like WKFileUploadPanel has the same bug.

[Olivia Barnett]

Created attachment 344211 [details]
Patch

[Olivia Barnett]

Created attachment 344212 [details]
Patch

[Tim Horton]

Comment on attachment 344212 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=344212&action=review

> Source/WebKit/UIProcess/ios/forms/WKFileUploadPanel.mm:288
> +            [currentPresentedViewController dismissViewControllerAnimated:YES completion:nil];

I think you probably still want to clear _presentationViewController in the completion handler.

[Tim Horton]

Comment on attachment 344212 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=344212&action=review

>> Source/WebKit/UIProcess/ios/forms/WKFileUploadPanel.mm:288
>> +            [currentPresentedViewController dismissViewControllerAnimated:YES completion:nil];
> 
> I think you probably still want to clear _presentationViewController in the completion handler.

(Otherwise I think this is a leak?)

[Olivia Barnett]

Created attachment 344222 [details]
Patch

[Tim Horton]

Comment on attachment 344222 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=344222&action=review

> Source/WebKit/UIProcess/ios/forms/WKFileUploadPanel.mm:288
> +            [currentPresentedViewController dismissViewControllerAnimated:YES completion:^{_presentationViewController = nil;

The first statement inside the block should be on the next line.

[Olivia Barnett]

Created attachment 344225 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 344225 [details]
Patch

Clearing flags on attachment: 344225

Committed r233502: <https://trac.webkit.org/changeset/233502>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.