Ubiquity window resizes in an odd way during Ubuntu installation when clicking "Install Now" after inputting disk encryption details

[Aaron Rainbolt]

This bug was discovered while doing an Ubuntu QA test, "Install (entire disk with lvm and encryption)" for Ubuntu Kinetic. I'm using the same host system specs as in this bug report: https://bugs.launchpad.net/ubuntu/+source/plymouth/+bug/1973150

While running the test, in step 14, immediately after clicking "Install Now", the VM appears to be processing the information its been given, when suddenly there's a sharp graphical glitch. It's hard to describe, it's sorta like the screen gets torn and stretched left and right for a second or something - you'll have to actually reproduce the bug to get a good idea of what it's doing.

(Edit: Upon further inspection, the Ubiquity window is resizing itself such that it fills the entire available horizontal area of the screen, at least on the screen size that virt-manager provides by default. It resizes like this, snaps back to normal position, resizes again, then snaps back again.)

Steps to reproduce the bug:

1: Download the Ubuntu Kinetic daily ISO from 2022-05-11. Here's the link: http://cdimage.ubuntu.com/daily-live/20220511.1/kinetic-desktop-amd64.iso
2: Open virt-manager, and ensure that you have a connection to "QEMU/KVM User session". (If you don't, you can create this connection in virt-manager by clicking "File", "Add Connection", selecting "QEMU/KVM user session" in the "Hypervisor" drop down, then clicking "Connect".
3: Create a new VM under QEMU/KVM user session. Select the Kinetic ISO downloaded above, set the OS to "Ubuntu 21.04" (that's the newest version my virt-manager recognizes), and give it 4 GB RAM, 2 CPU cores, and 20 GB of disk space.
4: Follow the steps in this test procedure: http://iso.qa.ubuntu.com/qatracker/milestones/433/builds/247872/testcases/1451/results

Expected results: In step 14, after clicking "Install Now", the VM should pause for a bit, processing the data you've given it, and then the screen should advance without any glitches.

Actual results: After clicking "Install Now", the screen throws a fit for a bit before going back to normal. Everything seems normal after the glitch.

ProblemType: Bug
DistroRelease: Ubuntu 22.10
Package: gdm3 42.0-1ubuntu7
ProcVersionSignature: Ubuntu 5.15.0-27.28-generic 5.15.30
Uname: Linux 5.15.0-27-generic x86_64
ApportVersion: 2.20.11-0ubuntu82
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Thu May 12 04:08:49 2022
InstallationDate: Installed on 2022-05-12 (0 days ago)
InstallationMedia: Ubuntu 22.10 "Kinetic Kudu" - Alpha amd64 (20220511.1)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no username)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gdm3
UpgradeStatus: No upgrade log present (probably fresh install)

[Aaron Rainbolt (arraybolt3)]

This bug also occurs in Ubuntu 22.04 (Jammy).

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/1973156

[Daniel van Vugt (vanvugt)]

Thanks for the bug report.

Screen tearing during mode changes is somewhat normal. Even more normal and even more visible in VMs. If that's the only problem then this may not really be a fixable bug. But I am only guessing. Please provide a video of the issue so we can confirm.

[Aaron Rainbolt (arraybolt3)]

I'm attaching two videos. One is the full installation procedure (including making the VM and logging into the new install), the other is a snippet out of the first video containing just the part of the installation that glitches out. I'm using the newest ISO from the QA tracker.

Launchpad doesn't seem to be accepting my full install video (it's 16.2 MB, maybe it's too big?), so I uploaded the videos to YouTube. Full install: https://youtu.be/X2OyHZXP51c Glitch: https://youtu.be/v9x7VgBSpHU

[Daniel van Vugt (vanvugt)]

Do you mean the window resizing glitch? That looks like a bug in the installer itself.

[Aaron Rainbolt (arraybolt3)]

You are correct. I didn't realize what I was looking at, but you're right, the window is resizing in a weird way.