vncserver doesn't start on Ubuntu if TigerVNC isn't active alternative

[CendioOssman]

Describe the bug
Debian/Ubuntu packages put TigerVNC under the "alternatives" system, as there are multiple projects that want to lay claim to names such as vncviewer or Xvnc.

If the currently active "alternative" isn't TigerVNC, then starting the vncserver service will fail. The reason is that it uses the normal names, which will at that point be some other implementation. E.g. RealVNC.

To Reproduce
Steps to reproduce the behavior:

1. Install RealVNC (TightVNC probably also works)
2. Install TigerVNC
3. sudo systemctl start vncserver@:#.service
4. Service fails to stay alive

Expected behavior
Service works even if TigerVNC doesn't own the generic names.

Client (please complete the following information):
N/A

Server (please complete the following information):

• OS: Raspberry Pi OS
• VNC server: TigerVNC
• VNC server version: 1.14.0
• Server downloaded from: github, built using contrib packages (modified for Debian)
• Server was started using: sudo systemctl start vncserver@:2.service

Additional context
Normally, this would be a Debian/Ubuntu issue. But since we also ship Ubuntu packages, we should at least fix those.

[CendioOssman]

Similar issue with the viewer. The desktop menu entry will start the currently active alternative, which might not be TigerVNC.

[CendioOssman]

The alternative system seems to have a bunch of bugs. Installing the server gives me these errors:

update-alternatives: warning: skip creation of /usr/share/man/man8/vncsession.8.gz because associated file
 /usr/share/man/man8/tigervncsession.8.gz (of link group vncsession) doesn't exist
update-alternatives: warning: skip creation of /usr/share/man/man8/vncserver.8.gz because associated file 
/usr/share/man/man8/tigervncserver.8.gz (of link group vncsession) doesn't exist
update-alternatives: warning: skip creation of /usr/share/man/man1/Xvnc.1.gz because associated file /usr/
share/man/man1/Xtigervnc.1.gz (of link group Xvnc) doesn't exist
update-alternatives: warning: skip creation of /usr/share/man/man1/x0vncserver.1.gz because associated fil
e /usr/share/man/man1/x0tigervncserver.1.gz (of link group x0vncserver) doesn't exist
update-alternatives: warning: skip creation of /usr/share/man/man1/vncpasswd.1.gz because associated file 
/usr/share/man/man1/tigervncpasswd.1.gz (of link group vncpasswd) doesn't exist
update-alternatives: warning: skip creation of /usr/share/man/man1/vncconfig.1.gz because associated file 
/usr/share/man/man1/tigervncconfig.1.gz (of link group vncconfig) doesn't exist

[CendioOssman]

Probably worth looking at how Debian packages TigerVNC:

https://salsa.debian.org/debian-remote-team/tigervnc/-/tree/master/debian?ref_type=heads

Not sure what the origin is for our packages, and why they differ from Debian and Ubuntu.

[james7x1]

I agree, I had this issue, so I use turboVNC for my server, but I don't have admin priv. on my client, so I use tigerVNC for client.