1678841 - "Run in Private Window" cannot be changed when `extensions.allowPrivateBrowsingByDefault: true`

Status: RESOLVED WONTFIX

(WebExtensions :: Untriaged, defect)

Description

[dkousvgi]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0

Steps to reproduce:

1. Set xpinstall.signatures.required to false in about:config

2. Install https://github.com/rufketo/isAllowedIncognitoAccess_demo/releases/tag/v1.0-incognito_allowed

3. Set extensions.allowPrivateBrowsingByDefault to false in about:config
   4.1. Open and reload the add-on's settings in about:addons
   4.2. Change the "Run in Private Windows" to "Allow".
   4.3. Click on the extension's icon.

4. Set extensions.allowPrivateBrowsingByDefault to true in about:config.
   6.1. Open and reload the add-on's settings in about:addons
   6.2. Click on the extension's icon.

5. Set extensions.allowPrivateBrowsingByDefault to false in about:config
   8.1. Open and reload the add-on's settings in about:addons
   8.2. Change the "Run in Private Windows" to "Don't Allow".
   8.3. Click on the extension's icon.

6. Set extensions.allowPrivateBrowsingByDefault to true in about:config.
   10.1. Open and reload the add-on's settings in about:addons
   10.2. Click on the extension's icon.

Actual results:

Step 4.1 and 8.1: Option "Run in Private Window" is displayed.
Step 6.1 and 10.1: No option "Run in Private Window" is displayed.

Step 4.3 and 6.2: extension.isAllowedIncognitoAccess(): true is shown.
Step 8.3 and 10.2: extension.isAllowedIncognitoAccess(): false is shown.

I.e. when extensions.allowPrivateBrowsingByDefault is true then the option "Run in Private Windows" is not visible, while extension.isAllowedIncognitoAccess() can still be either true or false.

See also https://github.com/rufketo/isAllowedIncognitoAccess_demo/blob/main/findings.md (top-level else branch).

extensions.allowPrivateBrowsingByDefault is true is the default in Tor Browser.

Expected results:

Step 6.1 and 10.1: Option "Run in Private Window" is displayed and affects the result of extension.isAllowedIncognitoAccess().

I.e. extensions.allowPrivateBrowsingByDefault should not affect if the option is displayed.

Comment 1

[dkousvgi]

Related:

• https://bugzilla.mozilla.org/show_bug.cgi?id=1678847
• https://bugzilla.mozilla.org/show_bug.cgi?id=1538546
• https://bugzilla.mozilla.org/show_bug.cgi?id=1557792
• https://bugzilla.mozilla.org/show_bug.cgi?id=1558075
• https://bugzilla.mozilla.org/show_bug.cgi?id=1536459

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Comment 3

[Alex Cornestean]

Hello,

I’ve managed to reproduce the issue on the latest Nightly (85.0a1/20201122213806), Beta (84.0b4/20201122152513) and Release (83.0/20201112153044) under Windows 10 Pro and Ubuntu 16.04 LTS.

Using the provided extensions, the results I’ve observed match the ones originally reported.

Comment 4

[Rob Wu [:robwu]]

This pref is going to be removed in bug 1661517.

Comment 5

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:mixedpuppy, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 6

[Shane Caraveo (:mixedpuppy)]

Use of allowPrivateBrowsingByDefault is not supported, it was used at the time as a feature fallback. Edge cases and issues have probably developed since as we don't work on supporting it being set to true. 1661517 will remove the setting.