[webextension] Websites hidden in Firefox Developer Edition

[greiner]

Environment

Adblock Plus 1.13.3 (gecko-webext)
Firefox 55.0b8 (developer edition)
Ubuntu 16.04

How to reproduce

1. Go to www.example.com
2. Install Adblock Plus web extension build
3. Go to www.example.com

Observed behaviour

The website content is visible before installing Adblock Plus but it's hidden afterwards.

Expected behaviour

The website content is visible before and after installing Adblock Plus

Further information

This is not reproducible on Firefox 54.0 (stable).

[mjethani]

Unable to reproduce this on Firefox 55.0b14 (64-bit) on macOS with either Adblock Plus 1.13.3 or the current master. I've also tried Firefox 55.0b8 specifically but no luck.

Thomas, did you have any specific filters or just the default (EasyList+AA)?

[greiner]

It also occurs with Firefox 55.0b14 (64-bit) on Ubuntu 16.04 using ​the current master with default settings (i.e. only EasyList and Acceptable Ads enabled) and no custom filters.

Here's some more info:

• Page remains hidden when disabling all filter lists
• Page remains hidden when disabling the extension
• Page is no longer hidden when disabling the extension and reloading the page
• Page is hidden when enabling the extension even without reloading the page
• Page is not hidden if it's served via any of the following protocols so presumably only HTTP(S) pages are affected:
  • about
  • file
  • ftp or ftps
  • moz-extension

[mjethani]

I have been unable to reproduce this on 55.0b14 (64-bit) on Ubuntu 16.04 running inside VirtualBox and the current master with the default settings.

Does this happen only on example.com or on any page served via HTTP(S)? It's hard to say why this would happen, at least example.com is a plain page with nothing going on. My best guess is that this is a memory issue. When the extension is loaded, it takes up memory, which somehow affects the page renderer.

Can you try resizing the browser window so the page gets rendered again?

Also, how much memory does the system have?

You could try playing with the values of ​browser.cache.memory.capacity and ​browser.sessionhistory.max_total_viewers in about:config.

What is the value of dom.ipc.processCount in your installation of Firefox? Maybe try increasing or decreasing that value as well.

Lastly, could you share what you see in the debug console? You can go to Debug Add-ons, enable add-on debugging, and then click on the Debug button to open the debug console, then copy and paste the contents into a file and upload it here. I'll try to compare with my output here to see if there's anything unusual.

[greiner]

Replying to mjethani:

Does this happen only on example.com or on any page served via HTTP(S)?

Yep, it affects any HTTP(S) page as far as I'm aware of.

Can you try resizing the browser window so the page gets rendered again?

No changes in the behavior.

Also, how much memory does the system have?

7.7 GiB

You could try playing with the values of ​browser.cache.memory.capacity

No changes in the behavior when changing browser.sessionhistory.max_total_viewers from -1 to 0 or 8.

In case it might be relevant, browser.cache.memory.enabled is set to true and browser.cache.memory.max_entry_size is set to 5120. Changing those has no effect.

and ​browser.sessionhistory.max_total_viewers in about:config.

No changes in the behavior when changing browser.cache.memory.capacity from undefined to 2048 or 32768.

What is the value of dom.ipc.processCount in your installation of Firefox?

4

Maybe try increasing or decreasing that value as well.

No changes in behavior when decreasing it to 2 or increasing it to 10.

Lastly, could you share what you see in the debug console?

No console output whatsoever. I've also checked out the Developer Tools for example.com and noticed the following:

• Adblock Plus disabled:
  • Inspector tab shows CSS rules and full DOM tree
  • No Adblock Plus tab in Developer Tools
• Adblock Plus enabled after opening Developer Tools
  • Inspector tab shows CSS rules and this DOM tree:

    <!DOCTYPE html>
    <html>
    </html>
    

  • No Adblock Plus tab in Developer Tools
• Adblock Plus enabled before opening Developer Tools:
  • Inspector tab is empty​ (i.e. no DOM tree, no CSS rules, no computed styles shown)
  • Adblock Plus tab in Developer Tools

[greiner]

When swapping the .dev-edition-default profile with the .default profile the issue no longer occurs so it appears to be something related to the browser profile and not to the browser variant.

I quickly tried to narrow the issue down to individual files but without success so far so I ​uploaded the profile contents if you want to take a look at it yourself.

[sebastian]

Sorry, but we switched to GitLab. If this issue is still relevant, please file it again in the ​new issue tracker.