Fenix: [Bug] Private custom tab opened when signing in to sync records history

[SL-Lee]

Steps to reproduce

1. Make sure sync is not turned on and you are in private browsing mode. Go to Main Menu > Settings > Turn on Sync.
2. Click on the Use email instead button. This will launch a private custom tab prompting the user to sign in.

Expected behavior

The private custom tab does not record any history, like normal private custom tabs opened from other applications.

Actual behavior

This private custom tab records the browsing history.

One behavior I noticed is that this is a "special" private tab - it does not follow the "Open links in private tab" option, rather, it follows the browsing mode settings was opened in. For example, even if "Open links in private tab" is enabled, opening settings when in normal browsing mode and then clicking on the Use email instead button will open a normal custom tab (not private).

Device information

• Android device: Oppo Reno 2, Android 9
• Fenix version: Nightly 200225 06:00 (Build #20560607)

[ekager]

I believe this should also be fixed by #8740

[AndiAJ]

Hi, still reproducible on the latest Nightly Build #20570604 from 02/26 using the following devices:
• Google Pixel 3a (Android 9)
• Huawei Mate 20 Lite (Android 8.1.0)
• Samsung Galaxy S7 (Android 7)
• OnePlus A3 (Android 6.0.1)
• LG Nexus 4 (Android 5.1.1)

► Video

[sv-ohorvath]

Note: History is recorded in any private custom tab, in Gmail for example.

[SL-Lee]

I don't think that's true. If a private custom tab records history, that is likely caused by #9037 (a stylistic issue), where the "Open links in a private tab" setting is off and Fenix was left in private browsing mode, leading users to believe that they are using a private custom tab when they are actually not.

Quote from #9037:

Custom tabs appear as private custom tabs, but pressing "Open in Firefox Nightly" opens it in a normal tab (which means it DOES record history -- hence may be related to #8716).

This issue focuses more on why clicking on why the "use email instead" button always opens a normal tab (and may appear as a private custom tab if you just so happen to be in private browsing mode when clicking the button [an effect of #9037]), and not respecting the "Open links in a private tab" setting.

In fact, if you click on the triple-dot menu and select "Open in Firefox Nightly" in the custom tab (after clicking on the "use email instead" button), you will see that it opens a normal tab, be it whether you are in a normal or private custom tab, or whether the "Open links in a private tab" setting is enabled or not.

[sv-ohorvath]

@SL-Lee thanks for the clarification.

[SL-Lee]

Note: Though #9037 does not reproduce anymore on Nightly 200929 17:11 (Build #2015766795), this issue is still reproducible on the same version. So this issue might not be caused by #9037 (as I had thought before).

[softvision-miralobontiu]

I was able to reproduce this issue on Beta 82.0.0-beta.4 with Samsung Galaxy Tab S6 (Android 10).

[softvision-miralobontiu]

The issue is reproducible on the latest RC 81.1.5 with Samsung Galaxy Tab S6 (Android 10).
I've signed in with a valid FxA account while accessing Settings - Turn on sync in private mode, and all the browsing was visible in History.