Unable to import files with custom UTI extension on IOS 13 - ios

Question

Since the update to IOS 13 importing custom UTI files is not working (works perfectly on devices with 12.4)
I've downloaded the simple working project form this page: https://www.raywenderlich.com/813044-uiactivityviewcontroller-tutorial-sharing-data , which i also used as a base for the sharing system of my app.
On IOS 13 (12.4 works), when get the sample file (from email o data folder) and click on Copy To App, IOS goes back to the main screen, and after a few seconds i get a Safari crash error.
This is the project info.plist section for exporting files:
<key>UTExportedTypeDeclarations</key>
<array>
<dict>
<key>UTTypeConformsTo</key>
<array>
<string>public.data</string>
</array>
<key>UTTypeDescription</key>
<string>Book Tracker Document</string>
<key>UTTypeIconFiles</key>
<array>
<string>book_320.png</string>
<string>book_64.png</string>
<string>book_44.png</string>
<string>book_22.png</string>
</array>
<key>UTTypeIdentifier</key>
<string>com.raywenderlich.BookTracker.btkr</string>
<key>UTTypeTagSpecification</key>
<dict>
<key>public.filename-extension</key>
<string>btkr</string>
<key>public.mime-type</key>
<string>application/booktracker</string>
</dict>
</dict>
</array>
</key>
Things i tried:
Add an UTImportedTypeDeclarations, with the same details as UTExportedTypeDeclarations ones as there is none in the project ---- STILL CRASH
In this post about at the end, was suggested to remove the section from the info.plist (Not modifying the Document Types section) and create it anew from the interface ---- STILL CRASH (it also causes an infinite loop in xcode when adding array items for public.filneame-extension or mime-type)
Various combinations of the solutions above
This is the main error i always get:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'
terminating with uncaught exception of type NSException
Full log is here: log
I'm kind of out out ideas! Please help!

Answer 1

I don't have the answer to your question but I have a similar problem with this same sample app from Ray Wenderlich. Unfortunately the comment section for this tutorial is closed.
I am using the "finished" version which has all the UTI information already set.
In my case I want to save the ".btkr" document to the Files application. That works OK but then if I tap on the .btkr document saved in Files, it opens the BookTracker application but quietly fails in the Book.swift importData(from url: URL) method.
I unraveled the guard statement into do/try/catch blocks and what I see is "The file “New Book.btkr” couldn’t be opened because you don’t have permission to view it." This is being thrown from the "let data = try Data(contentsOf: url)" statement.
The odd thing is if I share the same document via eMail, a tap on the .btkr attachment successfully opens the app and imports the .btkr just fine. Share via AirDrop works as well.
I do not know if this is only an iOS 13 bug because I no longer have any devices with older iOS's. Since the tutorials from Wenderlich are generally very good (this one is from February 2019, before iOS 13) I suspect your problem and my problem are iOS 13 bugs.

Answer 2

I'm seeing exactly the same thing here on my app. Wrapping readFromURL and writeToURL in between startAccessingSecurityScopedResource & stopAccessingSecurityScopedResource helped on my iPad running iOS 13.2.3, but I'm still seeing the Safari crash and unable to open the documents on the iPhone running 13.2.2.