Mostly I don't understand this discussion and probably I should not take
part in it. There has been no progress visible to me. The bug I reported
was assigned as duplicate to this, so if this is now fixed, should I report
the bug again?

Anyhow it appears to me, that to ordinary users sharing the PC, 18.04 is
useless without changing back to lightdm (I hope that still works after
latest development.) In practice that is not an option to most basic users,
so going back to 16.04 or another distro is likely the choice. I am
confused after reading all this development discussion. I would assume this
is being fixed, but getting worried.

ti 29. toukok. 2018 klo 5.05 Daniel van Vugt (<email address hidden>)
kirjoitti:

> Marco,
>
> It sounds like you're talking about the secondary bug. So let's reopen
> the cosmic task, awaiting that second fix. Cosmic presently has gdm3
> 3.28.0-0ubuntu2.
>
> ** Changed in: gdm3 (Ubuntu)
>        Status: Fix Released => In Progress
>
> --
> You received this bug notification because you are subscribed to a
> duplicate bug report (1768619).
> https://bugs.launchpad.net/bugs/1766137
>
> Title:
>   [regression] Password accepted but login fails (blank purple screen
>   and mouse pointer only)
>
> Status in gdm:
>   Fix Released
> Status in Release Notes for Ubuntu:
>   Fix Released
> Status in gdm3 package in Ubuntu:
>   In Progress
> Status in gnome-shell package in Ubuntu:
>   Invalid
> Status in gdm3 source package in Bionic:
>   In Progress
> Status in gnome-shell source package in Bionic:
>   Invalid
>
> Bug description:
>   [ Description ]
>
>   Due to a refcounting bug, a GDBusConnection was getting disposed when
>   it was still required. The symptom of this was that you couldn't log
>   in on the second attempt if you'd got your password wrong on the first
>   attempt. All you'd see is a blank purple screen and mouse pointer
>   only.
>
>   [ Test case ]
>
>   1. Boot to GDM
>   2. Click your username
>   3. Type the wrong password a couple of times, pressing enter after each
> time
>   4. Type the right password
>
>   If the bug is happening, after 4. the system hangs at a blank screen
>   with the mouse cursor. If you then switch to a VT or otherwise connect
>   to the machine, you can examine the journal and you'll see a
>   G_IS_DBUS_CONNECTION failure.
>
>   [ Fix ]
>
>   Marco and I worked upstream on this fix. We found out that there was a
>   problem like this-
>
>   The GdmClient has a shared GDBusConnection for its operations. The
>   first time  someone calls for it, it is created and stored in the
>   object's private structure. Subsequent calls return *a new reference*
>   to this same object. It turned out that the asynchronous method to get
>   the connection was accidentally unreferencing its object before giving
>   it to the caller if it was returning an already-existing connection.
>
>   For this to work properly, we need to nullify the pointer we stored
>   when the connection goes away, so we know when to make a new one.
>   There were some cases where we didn't add the weak references required
>   to do that. Those are also fixed.
>
>   [ Regression potential ]
>
>   Now we share connections more than we did before. We also more
>   carefully track when to clear our object. If we got this wrong, we
>   might end up leaking the connection or dropping it in even more cases.
>
>   [ Original report ]
>
>   WORKAROUND: After typing an incorrect password, click Cancel, then
>   click your name, then enter your password again.
>
>   ---
>
>   Trying to log into my session (Gnome, Xorg), if I enter the wrong
>   password before entering it correctly, the session doesn't load and I
>   get a purple screen, a mouse cursor, and an invisible but clickable
>   menu in the top right. If I enter it correctly the first time, there
>   is no problem.
>
>   I've replicated this from a fresh boot, after logging out and after
>   'sudo service gdm restart' from the Ctrl-Alt-F4 console.
>
>   This is a fresh install, and didn't occur when I was using a previous
>   install of 18.04 (until Friday).
>
>   ProblemType: Bug
>   DistroRelease: Ubuntu 18.04
>   Package: gdm3 3.28.0-0ubuntu1
>   ProcVersionSignature: Ubuntu 4.15.0-15.16-generic 4.15.15
>   Uname: Linux 4.15.0-15-generic x86_64
>   ApportVersion: 2.20.9-0ubuntu6
>   Architecture: amd64
>   CurrentDesktop: ubuntu:GNOME
>   Date: Sun Apr 22 20:31:13 2018
>   InstallationDate: Installed on 2018-04-22 (0 days ago)
>   InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64
> (20180421.1)
>   SourcePackage: gdm3
>   UpgradeStatus: No upgrade log present (probably fresh install)
>
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> https://bugs.launchpad.net/gdm/+bug/1766137/+subscriptions
>