Bug#614972: gdm3: can't login ("can't open display :0" in .xsession-errors)

[Vincent Lefevre]

On 2011-02-24 22:45:58 +0100, Josselin Mouette wrote:
> Le jeudi 24 février 2011 à 22:32 +0100, Vincent Lefevre a écrit :
> > I also think that
> >   * there should be some file mentioning the main differences (in
> >     particular, those not very visible) between gdm and gdm3;
> 
> This is not the same software. It is not compatible. Should we also
> document the differences with xdm, slim and kdm?

You miss the point that gdm3 is described as the successor of gdm:

  http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=613491

("please remove gdm from the unstable suite. It has been replaced
by gdm3.") and shares the same name (GNOME Display Manager)[*];
gdm3 even conflicts with gdm (but not with xdm, slim and kdm).
So, most admins will upgrade from gdm to gdm3 some day, thus users
will be interested in such a file.

[*] and the same product name in the upstream bug tracker? The README
file says: http://bugzilla.gnome.org/simple-bug-guide.cgi?product=gdm
(even though this URL is not valid).

> >   * there should be a dialog box at first install time mentioning
> >     these differences.
> 
> WTF?

Packages often do this when an upgrade yields incompatible changes
that require attention. For the reasons why I consider this as an
upgrade, see above. But if the end user is not the admin of the
machine, such a dialog box would be useless, so perhaps not a good
idea, finally.

> > > It’s already documented, in the user manual.
> > 
> > Which user manual?
> 
> yelp ghelp:gdm

That's not a standard way to read a manual file... perhaps under
GNOME, but gdm is just a display manager shared by several users,
and not all users use GNOME (FYI, I don't).

Moreover this manual doesn't seem to mention the XAUTHORITY
environment variable (that's the most important point, since
this is what the user really sees about the location of the
X authority file, and this is where something is likely to
break, everything else being mostly internals).

Also the manual should use the standard terminology, that is
at least one of:
  .Xauthority file
  authorization file
  X authority file
like in the main man pages about the subject (xauth(1), Xsecurity(7),
X(7), Xserver(1)).

-- 
Vincent Lefèvre <vincent at vinc17.net> - Web: <http://www.vinc17.net/>
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