EventKitUI/EKCalendarChooser needs access to contacts - why?

Question

I have an existing app since 2010, and with iOS 10 it is now required that the app is having strings in the Info.plist describing the usage, as explained here: http://useyourloaf.com/blog/privacy-settings-in-ios-10/

However, I already added the corresponding key in my Info.plist. Still, users report app crashes when the app tries to access calendars. One of the users now managed to send me a crash report, which looks like this:

Termination Reason: TCC, This app has crashed because it attempted to access 
privacy-sensitive data without a usage description.    
The app's Info.plist must contain an NSContactsUsageDescription key with a string value explaining to the user how the app uses this data.
Triggered by Thread:  2

Filtered syslog:
None found

Thread 0 name:  Dispatch queue: com.apple.main-thread
Thread 0:
0   libsystem_kernel.dylib          0x00000001812501a8 0x18124f000 + 4520
1   libdispatch.dylib               0x000000018113b7ec 0x181128000 + 79852
2   Contacts                        0x000000018aa2c63c 0x18a9c8000 + 411196
3   Contacts                        0x000000018a9f7c40 0x18a9c8000 + 195648
4   Contacts                        0x000000018aa08578 0x18a9c8000 + 263544
5   EventKitUI                      0x000000018f18b5a4 0x18f169000 + 140708
6   EventKitUI                      0x000000018f2a9628 0x18f169000 + 1312296
7   EventKitUI                      0x000000018f2aa3a8 0x18f169000 + 1315752
8   UIKit                           0x000000018843b1b4 0x1880e8000 + 3486132

Now the question is, why is my app needing access to contacts, but my app only wants to read/write calendars?

In the crashing code I am opening a EKCalendarChooser, and previously I asked the user for permission using eventStore requestAccessToEntityType:EKEntityTypeEvent completion:(...)

In my Info.plist I have:
<key>NSCalendarsUsageDescription</key>
<string>Storing of leave data</string>

So how do I fix this? Must I add NSContactsUsageDescription as indicated by the crash report? Why? And will it lead to a popup prompt for contacts access, which would most users probably consider as a bad thing?

Note: the weirdest thing is, that on none of my devices this crash can be reproduced, I only have a couple of users reporting this kind of crash.

Answer 1

I've just had the same problem and believe it is because the EKCalendarChooser can show which of your Contacts is sharing a calendar. I just turned off all sharing including removing family members from iCloud Family and it no longer requires access to Contacts. I then tried to share a calendar with a contact using the EKCalendarChooser and it prompted for permission after I had chosen the contact.

It is a bit of a pain, but the solution is to probably go ahead and add a usage description that tells the user permission is required to show / modify calendar sharing details. Another (and more painful) alternative would be to create your own view for choosing calendars.

I'm not sure if this is intentional by Apple or a bug as I don't know if there is any way for developers to gain access to the contact information from the EKCalendarChooser view anyway.