After installaing and removing lightdm-gtk-greeter lightdm is left in a not working state

[_dan_]

expected behaviour:
unity greeter is used again

actual behaviour
lightdm wont start, falling back to console

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: lightdm 1.2.0-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-22.35-generic 3.2.14
Uname: Linux 3.2.0-22-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.0-0ubuntu4
Architecture: amd64
Date: Mon Apr 9 10:56:19 2012
SourcePackage: lightdm
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Lionel Le Folgoc (mrpouit)]

lightdm-gtk-greeter and unity-greeter share similar postinst scripts, so that'd be great if Sebastien could elaborate...

[Lionel Le Folgoc (mrpouit)]

I meant postrm scripts, of course. ;-)

[Sebastien Bacher (seb128)]

Lionel, why do you consider it a lightdm bug if lightdm-gtk-greeter change the config and doesn't restore it when uninstalled to let it in a broken state? It seems it's the greeter package changing the config and breaking it..

Oh, and nobody said that unity-greeter doesn't have the same bug, still it doesn't make it a lightdm bug, could you give details on why you think it's ok for the greeter to change the config on install and let a buggy one when being uninstalled?

[Lionel Le Folgoc (mrpouit)]

The unity-greeter is affected as well, but you read "lightdm-gtk-greeter" is the description, so you reassign to lightdm-gtk-greeter and ignore the unity-greeter issue so that you've less bugs showing on your qa stats, I guess?

So we can argue all day about your incredible bad faith, or we can think about something to fix this bug, your call.

Anyway, this is an issue with all greeters currently.

[Sebastien Bacher (seb128)]

> The unity-greeter is affected as well, but you read "lightdm-gtk-greeter" is the description, so you reassign to lightdm-gtk-greeter and ignore the unity-greeter issue

? the bug didn't state that unity-greeter was affected, I quote the title "After installaing and removing lightdm-gtk-greeter lightdm is left in a not working state", so I assigned it to the package listed in the title because that's where it needs to be fixed..

> so that you've less bugs showing on your qa stats, I guess?

what sort of weird comment in that?
- I don't "own", "maintain", or "work on" lightdm, I just help triaging desktop bugs coming
- the bug didn't get closed, that would be no "stats" change
- where are those "qa stats" you talk about?
- why should I let a bug assigned to the wrong comment?

> So we can argue all day about your incredible bad faith, or we can think about something to fix this bug, your call.

oh, personal attacks now? you should calm down, I only reassigned the bug to the package listed in the title (like I reassign a dozen bugs from lightdm to unity-greeter every week), what's the issue to have bugs on the correct source? I didn't stop that unity-greeter had the same issue until you mentioned it and then I didn't reassign back but did "also affect" to show it affects 2 sources (though it seems I failed to do lightdm->unity-greeter for the second line at the same time)

[Sebastien Bacher (seb128)]

"I didn't stop that unity-greeter" -> "I didn't notice that unity-greeter"

[Lionel Le Folgoc (mrpouit)]

(In French, for Sébastien: Mais oui, bien sûr, dire que quelqu'un est de mauvaise foi c'est une attaque personnelle... On aura tout lu.)

Yes, I think you're often too prompt to reassign bug reports when they don't mention gnome/unity/something-managed-by-the-desktop-team, without thinking about the real issues or even reading the bug... And we usually end up doing some funny ping pong sessions because we're both stubborn and don't listen to each other?

Back on topic:
* lightdm-gtk-greeter and unity-greeter share similar maintainer scripts
* they both use --keep-old in postinst, so there's no way installing lightdm-gtk-greeter after unity-greeter (or the opposite) would set gtk-greeter by default
* in the postrm, --remove will only remove the greeter if it's the one currently set in the config file.

So the issue is that our current postrm scripts will set greeter to "" when we remove the greeter currently set in the config file, and so break lightdm... We can patch lightdm-set-defaults to select a random greeter instead of doing that, or switch to what Yves-Alexis did in Debian (manage greeters with update-alternatives). Voilà.

[_dan_ (dan-void)]

Dont know if that helps:

As far as i recall from when i experienced this bug, installing lightdm-gtk-greeter triggered an update-alternative when installing, not when removing tho.

when installing lightdm-gtk-greeter i had to manually edit lightdm.conf to greater-session=lightdm-gtk-greeter to usethe lightdm greeter, when removing the greeter and changing the key back to greeter-session=unity-greeter lightdm failed to start.
i have no clue about lightdm internals, nor how greeter actually work, thats purely from an users POV but having a key in the config file and partially ignoring it and having redundant update-alternatives which partly work seems very very confusing and irritating to me. there may be a technical reason behind it, or something i dont get/understand, but well, i am just a user

[Sebastien Bacher (seb128)]

> (In French, for Sébastien: Mais oui, bien sûr, dire que quelqu'un est de mauvaise foi c'est une attaque personnelle... On aura tout lu.)

c'est déplacé comme commentaire dans un bug tracker c'est tout (end of the discussion on that topic)

> Yes, I think you're often too prompt to reassign bug reports when they don't mention gnome/unity/something-managed-by-the-desktop-team, without thinking about the real issues or even reading the bug... And we usually end up doing some funny ping pong sessions because we're both stubborn and don't listen to each other?

Right, side effect of having to deal with tons of bugs, we can't spend hours on every ticket and errors happen, no need to come back with personal attacks and "bug stat" speculations when that happens. I'm happy to admit I do reassing bugs quickly and do errors sometimes (or often if you prefer), nobody is perfect

> Back on topic:
> * lightdm-gtk-greeter and unity-greeter share similar maintainer scripts
> * they both use --keep-old in postinst, so there's no way installing lightdm-gtk-greeter after unity-greeter (or the opposite) would > set gtk-greeter by default
> * in the postrm, --remove will only remove the greeter if it's the one currently set in the config file.

> So the issue is that our current postrm scripts will set greeter to "" when we remove the greeter currently set in the config file, and so break lightdm... We can patch lightdm-set-defaults to select a random greeter instead of doing that,

Selecting as a random greeter is a no from the discussion we had with Robert in the past, he thinks that could be a security issue and not something reliable, it's better to break the config and have xfailsafe kick in to let you fix,reset the configuration

Why is the greeter set to ""? That seems a bug in lightdm-set-defaults --remove, i.e it should remove the line (and let lightdm goes back to use its build time default)?

> or switch to what Yves-Alexis did in Debian (manage greeters with update-alternatives). Voilà.

I will let others to decide on that, I hate alternatives they are overcomplex and tend to create issues, but I will not stop the lightdm maintainer to use them if he wants.

One other questions on that issue would also to know why the xfailsafe mode doesn't kick in, that's what is supposed to happen when no greeter can be loaded

[Sebastien Bacher (seb128)]

@_dan_: your issue is a different one, could you open a new bug with your lightdm.log attached?

[Lionel Le Folgoc (mrpouit)]

> Why is the greeter set to ""?

From a quick look at the source, g_key_file_set_string (keyfile, key_group, key_name, ""); is used, but g_key_file_remove_key (keyfile, key_group, key_name, &err); should probably be used instead (I'll try to patch and see if lightdm behaves better).

> why the xfailsafe mode doesn't kick in

In the lightdm log (x-0.log), I can see "Server terminated successfully (0).". I guess that's why xfailsafe thinks everything went fine?

[_dan_ (dan-void)]

@Sebastien its not a different one, its the thing i reported in the first place just a bit more information.

[Sebastien Bacher (seb128)]

no, if you set "greeter-session=unity-greeter" and it's ignored you have another issue that the configuration is not working (though that's weird)

[_dan_ (dan-void)]

nvm

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Sean Davis (bluesabre)]

Is this still an issue with either greeter?

[_dan_ (dan-void)]

Idk, that was 9 years ago, you can close it.