2019462 - Stretched Kit wallpaper when homepage doesn't show any content and composable toolbar at the bottom is used

Status: VERIFIED FIXED

(Firefox for Android :: Homepage, defect)

Description

[[e-mail]]

Steps to reproduce

• Disable all items in your HNT
• Have toolbar on the bttm
• Configure the Kit wallpaper.
• Navigation to a site,
• Opening a new tab
• Check Kit wallpaper

Expected behavior

Kit should be displayed correctly.

Actual behavior

Kit here should be pegged to the bottom right corner of the visible screen, but it looks like the wallpaper is being stretched beyond the edge of the screen. It flashes correctly for a split second when opening a new tab, but it reverts to the stretched position(?) when the keyboard disappears.

Device information

• Firefox version: Firefox 148.0
• Android device model: Pixel 9 Pro XL.
• Android OS version:

Any additional information?

• Compose toolbar needs to be enabled

Comment 1

[[e-mail]]

Attachment: screen-20260224-162509-1771979095616.mp4

Comment 2

[Petru-Mugurel Lingurar [:petru]]

This was hard to investigate since for me it reproduces only when the build is non-debuggable.
I can see the issue in a non-debuggable dev build and I can't see it in a debuggable Nightly build.

Think I though found the extra conditions for it:

• a non-debuggable build - since it's faster than a debuggable one
• have less/no home screen widgets shown - less functionalities means faster execution of the code
• the composable toolbar at the bottom - searching through the composable toolbar has the entire home screen content accounting for the keyboard - to ensure the bottom toolbar is shown above the keyboard. The View based toolbar had search happen in a separate screen so the home content would not be touched in any way.

What happens (sometimes) is that:

• the wallpaper is set to be applied when the home screen opens .
  This starts a coroutine for applying it "in background" and when done save the name of this wallpaper in memory.
• since the user tapped the "+" button to start a new search we open the keyboard
• very soon after the initial request to apply the wallpaper (but before this finishes) a new request to apply the wallpaper comes from here.
  This request also gets to apply the wallpaper again and for this it scales the wallpaper to best fit the current screen dimensions. This scaling process also considers the keyboard height to avoid the issue from bug 1827107, keyboard which might be shown because the user already entered in search mode.
  So the screen will appear to be a lot longer leading to the wallpaper being scaled to match.
  Less/no other widgets on the home screen is a precondition also which leads to less code to execute and higher chances of the two wallpaper set calls to overlap.

Comment 3

[Petru-Mugurel Lingurar [:petru]]

Being a race condition with this many variables (that somehow get to align just right) means we have multiple possible approaches to avoid the issue.
I think the easiest and most natural is to observe wallpaper updates to refresh them only after the initial wallpaper set operation finished.
This would avoid the extra work to set again the same wallpaper and avoid also the issue reported here.

Comment 4

[Petru-Mugurel Lingurar [:petru]]

The flicker issue seems to be a separate bug, opened bug 2019584 for it.

Comment 5

[Petru-Mugurel Lingurar [:petru]]

Attachment: Bug 2019462 - part 1 - Have Fragment.consumeFrom return a Job r=#android-reviewers

This will allow checking if an operation is active and allow allow stopping it.

Comment 6

[Petru-Mugurel Lingurar [:petru]]

Attachment: Bug 2019462 - Start observing wallpapers updates only after one is first set r=#android-reviewers

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/62c571bdaa56
https://hg.mozilla.org/integration/autoland/rev/6634949b28a8
Start observing wallpapers updates only after one is first set r=android-reviewers,pollymce

Comment 8

[Silaghi Andreea]

https://hg.mozilla.org/mozilla-central/rev/6634949b28a8

Comment 9

[Adina Petridean QA [:apetridean]]

Attachment: screen-20260319-174742-1773935247148.mp4

Verified as fixed on the latest Nightly 150.0a1 with Google Pixel 10 (Android 16).

Comment 10

[Petru-Mugurel Lingurar [:petru]]

Attachment: Bug 2019462 - Start observing wallpapers updates only after one is first set

Original Revision: https://phabricator.services.mozilla.com/D285042

Comment 11

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/42f2ff8ba21b
https://hg.mozilla.org/releases/mozilla-release/rev/16e9fa8b6914

Comment 12

[Vasilica Tamas (Android QA) [:vtamas]]

Attachment: Recording_20260331_130458.mp4

This issue is verified as fixed on Firefox 149.0.1 using Samsung Galaxy s24 Ultra (Android 16). Confirming that the kit wallpaper is correctly displayed.