dotnet 7.0 and dotnet 8.0 are incompatible (host part)

[bcornec]

Context: Ubuntu 22.04 LTS up to date

$ sudo /usr/bin/apt-get -y -o "Dpkg::Options::=--force-confdef" -o "Dpkg::Options::=--force-confold"
install aspnetcore-runtime-6.0 dotnet-runtime-6.0 dotnet-sdk-6.0 aspnetcore-runtime-7.0 dotnet-runtime-7.0 dotnet-sdk-7.0 aspnetcore-runtime-8.0 dotnet-runtime-8.0 dotnet-sdk-8.0 dotnet-host
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
dotnet-host-7.0 : Conflicts: dotnet-host
E: Unable to correct problems, you have held broken package

Whatever we try it seems it's impossible to have both dotnet-host for v7 and v8.
The other packages can be installed alongside the other version, but not the dotnet-host one.

A new compatible package should be provided for v7, which allows update or simultaneous install with dotnet-host-8.0

At least that should be correctly documented in the installation doc (which doesn't mention dotnet-host BTW).

Formerly opened as dotnet/aspnetcore#52352 but closed without good reason, so retrying here as it may be more relevant as a place.

[baronfel]

This really sounds like you have mixed packages - some coming from the distro and some coming from Microsoft. Can you take a look at the troubleshooting docs here and see if that's the case? https://learn.microsoft.com/en-us/dotnet/core/install/linux-ubuntu#troubleshooting