Certain users fail to download apple-app-site-association when downloading the app

Number:rdar://33893852 Date Originated:15/08/2017
Status:Open Resolved:
Product:Tail Product Version:All
Classification:Bug Reproducible:No
My app requires users to authenticate with another app before being redirected back to my app via  a Universal Link. However, for certain users the apple-app-site-association file is never downloaded.

It is my understanding the this file is supposed to be downloaded either when the app is first downloaded or when the app updates, however this functionality is clearly broken in some cases.

For the users for whom this occurs the file is never downloaded, no matter how many times they delete and reinstall the app, this makes me think that there is some kind of issue whereby the daemon which handles the downloading of the file can crash for some users, thus preventing them from benefiting from Universal links.

For at least one user we seemed to be able to resolve the issue by having them delete the app (for the 4th time!) restart their phone, then reinstall the app immediately afterwards. This seems to me that it would lend weight to the daemon crashing argument as the user was able to download the file immediately after restarting, before the daemon had a chance to crash again.

This issue is of the utmost importance given that the correct functioning of universal links is essential to the functionality of my app.

Steps to Reproduce:
We have never been able to reproduce this issue in-house, however it has affected around 1% of our users.

Expected Results:
GET request made for the apple-app-site-association file present on our server from the users iPhone.

Observed Results:
No GET request made for the apple-app-site-association file present on our server from the users iPhone.





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