Invalid / malformed filters shouldn't affect the processing of valid filters

[Gingerbread Man]

Environment

Me: Firefox 31.0a2 (2014-05-08) • Adblock Plus 2.6.0.3810
Reporter: Firefox 30.0b2 • Adblock Plus 2.6.0.3807
​https://adblockplus.org/forum/viewtopic.php?f=1&t=22999

How to reproduce

1. Starting with a fresh profile and a new installation of Adblock Plus, go to ​the all subscriptions page and add the ROList subscription.
2. In the Filter Preferences window - Filter Subscriptions tab, uncheck "Allow some non-intrusive advertising", then check "Adblock Warning Removal List".
3. On the Custom Filters tab, add the following filter (suggested by EHH when trying to hide the adblock warning): mangastream.com##.pull-right.message-ld
4. Open the Blockable Items Pane.
5. Go to ​http://mangastream.com
6. The adblock warning shows next to the logo in the top left. The blockable items pane doesn't show the custom filter being applied. The filter preferences window shows zero hits for the filter.
7. In the Filter Preferences window - Filter Subscriptions tab, uncheck "Adblock Warning Removal List", then uncheck "ROList". As soon as you do, the adblock warning message disappears.
8. Re-enable "Adblock Warning Removal List", then re-enable "ROList".
9. The adblock warning stays gone. On a page reload, the blockable items pane shows the filter being applied and the filter preferences window shows 2 hits on the filter. The issue doesn't show up again after that, even after clearing the cache, cookies and offline website data.

As noted at comment 4, this is due to the following malformed filters in ROList:

bancuri.ro##.art-blockcontent-body A > IMG and ||ne-jucam.net/maimutica.swf
distanta.ro##DIV[style$="width: 336px; height: 280px;�]
distanta.ro##DIV[style*="display: block; background-color: white; �]

Observed behavior

The adblock warning shows next to the logo in the top left. The blockable items pane doesn't show the custom filter being applied. The filter preferences window shows zero hits for the filter.

Expected behavior

The adblock warning next to the logo in the top left shouldn't be visible. The blockable items pane should show show the custom filter being applied. The filter preferences window should show 2 hits for the filter.

[Gingerbread Man]

Element hiding filter not applied

[barbaz]

Most likely not an Adblock Plus issue, but rather these three bad hiding filters in ROList

bancuri.ro##.art-blockcontent-body A > IMG and ||ne-jucam.net/maimutica.swf
distanta.ro##DIV[style$="width: 336px; height: 280px;�]
distanta.ro##DIV[style*="display: block; background-color: white; �]

[philll]

@arthur: please reevaluate due to https://issues.adblockplus.org/ticket/454#comment:4

[arthur]

The maintainer fixed the filters and it's no longer happening.

[Gingerbread Man]

Invalid reads like a bad joke. "There's a filter problem" wasn't the report.

This isn't the first time this has happened, and it won't be the last. If you considered it not worth the time and effort, it would've at least made some sense if this was marked wontfix.

[mapx]

It's strange indeed. It seems that one bad filter could affect all the other filters (or subscriptions !) or the process of blocking / hiding the ads. So, a bad filter should be only ignored.

[trev]

Replying to Gingerbread Man:

Invalid reads like a bad joke. "There's a filter problem" wasn't the report.

The way element hiding is implemented in Firefox, preventing side-effects of bad filters isn't really possible. Also, we cannot validate each rule - there are simply too many of them, that would waste too much time even if validating on download (which wouldn't really be sufficient, whether a particular rule is valid or not depends on the Firefox version among other things). The current approach is making sure that an appropriate message shows up in the Browser Console. Also, #493 and #494 should make is far less likely that invalid filters even make it into the lists.

So it's either rejected or duplicate - pick whichever resolution you prefer.