DNS filterlists are updated on the disk without reloading DNS filtering which causes random filtering issues

[ameshkov]

Here's the problem:

1. DNSProxy indexes DNS filterlists files and loads full rule texts in a lazy manner
2. When you update the DNS filterlist file AND do not reload DNS filtering, it uses the old index to access the NEW file. This causes random issues - for instance, it will read just a part of the rule com^ instead of ||example.com^.

Probably, this is done during background fetch.

This is rather easy to reproduce:

1. Subscribe to a custom blocklist with the only rule:

   ! this is comment
   ||example.com^

2. Change that blocklist to:

   ! this
   ||example.com^

3. Wait for the background fetch to happen, the filterlist will be updated on the disk
4. It will start blocking all .com domains because the old index points to .com^

[sfionov]

From support chat:

[ghost]

I'm experiencing this issue!

Was noticing random things being blocked in local filtering and wasn't understanding why.

Anything I can do in the meantime?

@ameshkov @IvanIin

[ameshkov]

@planet0 next update should resolve it for good.

[ghost]

@ameshkov Would turning off background app refresh for AdGuard help with this issue in the meantime?

[ameshkov]

@planet0 yep, it will help