Snippet filters don't work if ABP anti-circumvention filter list is removed and readded

[mjethani]

Environment

Adblock Plus 3.4 pre-release (​development build)

How to reproduce

1. Do a fresh install of Adblock Plus
2. Go to yandex.ru, search for "rent a car", and observe that there are no ads
3. Open the options page and uncheck "ABP Anti-Circumvention Filter List", then recheck "ABP Anti-Circumvention Filter List"
4. Repeat step 2

Observed behaviour

Ads are visible.

Expected behaviour

Ads should be hidden.

Additional notes

This happens because snippet filters will be used only if they come from the ABP anti-circumvention filter list, but this is determined at the time of installation from the subscriptions.xml file. When the UI readds the list, it doesn't set the type property of the Subscription object the way it is done during first run.

The proper fix would be for the UI to set the type property of the newly created Subscription object to "circumvention".

Note that before the change for #6855 you would not be able to reproduce this issue without restarting the extension before readding the anti-circumvention filter list; that change has only made the underlying issue more apparent, this is not a regression because of that change.

Resolution

This was fixed by #6975 in adblockpluscore by hardcoding the URL of the anti-subscription filter list.

See follow-up issue #6977 for a more ideal fix.

Hints for testers

See #6975.

[mjethani]

I would consider this is P1.

[mjethani]

Actually given that snippet filters may have been disabled for at least some users as a result of this behavior, perhaps it's better to do the fix in core instead.

[sebastian]

I agree this is P1, and therefore should be addressed before we release 3.4.

Handling this in core seems like a good idea, rather than having every code that adds subscriptions, look into subsciption.xml to figure out which attributes to set for the added subscription.

[mjethani]

The fix is now in adblockpluscore: changeset ​2d1ef04ca952 (git: ​fb82c4a).

[greiner]

Wouldn't it be better to look up its type from subscriptions.xml rather than hardcoding the URL for the Anti-CV list in the code?

In general, it'd be great if we could have a centralized data structure that's provided by Core from which we can extract this kind of information so that we don't fetch and parse subscriptions.xml in multiple places anymore.

[mjethani]

I agree, I have filed #6977 for the proper fix, this fix is only for 3.4.

[Ross]

This looks fixed (I think). Mainly tested by checking if the snippets appear in the devlog after removing/re-adding the subscription as some are being circumvented.

ABP 3.3.2.2172
Firefox 62 / 51 / Windows 10
Chrome 69 / 49 / Windows 10
Opera 56 / 36 / Windows 10