Nested !#if/!#endif directives not evaluated properly

[krystian3w]

Prerequisites

• I verified that this is not a filter issue
  • Filter issues MUST be reported at filter issue tracker
• This is not a support issue or a question
  • Support issues and questions are handled at /r/uBlockOrigin
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue
  • Your issue may already be reported.
• I tried to reproduce the issue when...
  • uBlock Origin is the only extension
  • uBlock Origin with default lists/settings
  • using a new, unmodified browser profile
• I am running the latest version of uBlock Origin
• I checked the documentation to understand that the issue I report is not a normal behavior

Description

Two conditions for limiting the operation of filters do not work well, the second condition is may not interpreted.

uBlockOrigin/uAssets#3482 - where used two conditions.

A specific URL where the issue occurs

https://www.google.com/search?q=search

Steps to Reproduce

1. Open expample website

2. In my filters panel put expample conditions:

   !#if env_firefox
   !#if env_mobile
   google.*###main > div
   !#endif
   !#endif
   

   and save.

3. Refresh website - almost all div should be hidden.

4. The second condition is somewhat ignored and cuts out the content despite the incompatibility of the platfrom.

Expected behavior:

The second condition should be included.

Actual behavior:

The second condition is not included?

Your environment

• uBlock Origin version: 1.17.0
• Browser Name and version: Firefox 62.0.2
• Operating System and version: Windows 7 Professional x64 PL language edditon.

[uBlock-user]

Duplicate of #183

[gorhill]

Does not seem to be a duplicate, there is no syntax error in the directives -- which is what #183 was about.

[uBlock-user]

google.*###main > div filter doesn't get applied, is that expected response ? My Filters count remains 0 out of 0. Nvm, I was testing on Chromium.

[gorhill]

If I understand correctly he is saying all divs end up being hidden, while this should not be the case if not using Firefox for Android.

[uBlock-user]

search bar along with Google logo doesn't get hidden except that everything else is hidden.

[uBlock-user]

The second condition should be included.

The second condition won't get fulfilled if you're not on Firefox for Android, so I don't see the issue with that.

[krystian3w]

If I understand correctly he is saying all divs end up being hidden, while this should not be the case if not using Firefox for Android.

Yes.

search bar alongwith Google logo doesn't get hidden except that everything else is hidden.

I did not check this out, I noticed that it started hidding div[data-hveid] out in the simulator with mobile UA activated, so I preferred to report.

---

As for the problem, I even recreated it in Opera 56 - it also hides most of the elements and is the top browser bar.

!#if env_chrome
!#if env_mobile
google.*###main > div
!#endif
!#endif

/

!#if env_chromium
!#if env_mobile
google.*###main > div
!#endif
!#endif

but uBO do not support officially Mobile Yandex browser.

---

The second condition won't get fulfilled if you're not on Firefox for Android, so I don't see the issue with that.

Then rely on the perfection of the filter.

[uBlock-user]

@gorhill Do all preparsing directives have to be true for the filter to apply ?

[gorhill]

Yes.

However looking at the code, I see that directives which evaluate to false will be ignored if contained in a directive which evaluates to true -- this is a bug. I can't remember what was my thinking when I wrote that code, but my answer to @grenzor in #183 says that I was expecting the code to deal properly with !#if within !#if.

[krystian3w]

Possible add in the feature this syntax:

!#if (!adguard_ext_android_cb && !adguard_ext_safari && !adguard_app_ios)

similar proposed by @mapx-

---

!#if !adguard_ext_android_cb 
!#if !adguard_ext_safari 
!#if !adguard_app_ios

! filter for modern uBlock Origin and AdGuard Adblocker / AdGuard APP (macOS, Windows, Android).
! "modern" - support `:style()` filters.

!#endif
!#endif
!#endif