Ubuntu PPA gnuradio-releases doesn't actually install

[Paul Boven]

Hi everyone,

Ubuntu 20.04 (Focal) ships with GNU Radio 3.8.1.0~rc1-2build2. I have 
added the gnuradio-releases PPA on my machine, assuming that it would 
get me the slightly newer release version of 3.8.1.0. However, after 
adding the PPA, the Ubuntu provided release candidate version still gets 
installed, not the PPA version.

apt policy gnuradio:
  Installed: 3.8.1.0~rc1-2build2
  Candidate: 3.8.1.0~rc1-2build2
  Version table:
 *** 3.8.1.0~rc1-2build2 500
        500 http://nl.archive.ubuntu.com/ubuntu focal/universe amd64 
Packages
        100 /var/lib/dpkg/status
     3.8.1.0~gnuradio~focal-1 500
        500 http://ppa.launchpad.net/gnuradio/gnuradio-releases/ubuntu 
focal/main amd64 Packages

So the package is seen as available, but the OS prefers the rc1 version. 
Is this because the version number string is considered 'higher' 
alphabetically than the version string of the PPA version? 
(3.8.1.0~rc1-2build2 against 3.8.1.0~gnuradio~focal-1). Did we get the 
naming or version numbering convention wrong in the PPA?

After some research, I managed to install the PPA version:
sudo apt install gnuradio=3.8.1.0~gnuradio~focal-1

This fails at first, because all of the Ubuntu provided gnuradio library 
packages have 3.8.1.0 in their name, whereas the PPA packages don't - so 
they are not seen as up/downgrades, and instead, massive file conflicts 
ensue. These can be resolved by first removing the gnuradio package, and 
all its dependencies, and then installing the gnuradio from the PPA. 
This will then pull in all the dependencies from the PPA as well.

But on the next 'apt upgrade', the PPA version will be replaced again by 
the OS version (causing the same level of mayhem), unless I start 
pinning stuff.

(I don't particularly need anything that's in the release version, 
versus the release candidate version, as far as I know - I was just 
surprised that when switching to this PPA, I didn't actually get the 
release version and had to investigate).

Regards, Paul Boven.