Bug 290847 – File downloads and inline file display in iOS 18.4 Web App lead to navigation-less state

• Component: New Bugs
• Status: NEW

[Tobias Grasse]

Created attachment 474792 [details]
Screenshot of file download in iOS 18.4 PWA resulting in navigation-less state

When installed as a Web App on the user's home screen, any file download (i.e. `<a href="myfile.pdf" download>` together with a `Content-Disposition: attachment` header) will result in an “Open in …” splash screen that prohibits further navigation inside the Web App. The only resolution is to force-close and relaunch the web app.

If the file is accessed without a `Content-Disposition: attachment` header, both mobile Safari and web app instances display the PDF inline. This PDF preview also has no way for users to navigate back in the web app.

I published a minimal reproduction on GitHub: https://github.com/tobias-grasse/ios-pwa-download-reproduction 

This is in response to Jen Simmons' reply on Mastodon (https://front-end.social/@jensimmons/114257798737382494) who kindly asked me to file this here.

[Tobias Grasse]

FYI: macOS handles file downloads in web apps correctly. When I install the same web app using Safari's “Add to Dock” feature and then click a download link, it saves the file to my Downloads folder and does not change navigation state in the web app.

[Jen Simmons]

@Tobias, Did this work in the past, and then stop working? Or did it never work? (Or perhaps you don't know, which is ok, too. But helpful if you do know.)

[Tobias Grasse]

@Jen, I'm afraid I don't know if this ever worked. However, I can confirm that the described behaviour also occurs on an iPhone 8 running iOS 16.7.10. That's the oldest test device I currently have access to.

There's a Stackoverflow thread mentioning at least a “Done” button on iOS 12 and before:
https://stackoverflow.com/questions/58492495/how-to-download-image-from-pwa-in-safari-ios13#:~:text=On%20iOS%2012%20there%20was%20a%20button%20'Done'%20and%20preview%20of%20the%20image

This SO thread shows a screenshot with a “Done” button on iPad with 13.3, but I'm not sure if they are just conflating iOS PWA's cross-origin behaviour with same-origin: first opens an in-app Safari overlay with basic controls and a Done button, latter stays in the PWA frame.
https://stackoverflow.com/questions/59843280/ios-safari-back-button-on-filedownload-screen-sometimes-missing

[Radar WebKit Bug Importer]

<rdar://problem/148831174>