Buster apt pinning - refined instructions

[smurphos]

Hi,

• Renames the debian-chromium.list to z-debian-chromium.list and debian-chromium.prefto z-debian-chromium.pref This avoids the issue where packages with the same name and version in both buster and focal are incorrectly flagged as being installed from buster and are reported as candidates for downgrade to the focal version - https://github.com/linuxmint/doc-user-guide/issues/1

• Changes the default pinning rule to -10. This avoids users being able to install other non chromium related packages that are only in the Buster repos and not in the Focal repos.

• Add some additional rules for chromium dependencies that are only available in Buster.

Supersedes https://github.com/linuxmint/doc-user-guide/pull/4

[smurphos]

steve@steve-VirtualBox:~$ apt policy
Package files:
 100 /var/lib/dpkg/status
     release a=now
 -10 http://security.debian.org buster/updates/main i386 Packages
     release v=10,o=Debian,a=stable,n=buster,l=Debian-Security,c=main,b=i386
     origin security.debian.org
 -10 http://security.debian.org buster/updates/main amd64 Packages
     release v=10,o=Debian,a=stable,n=buster,l=Debian-Security,c=main,b=amd64
     origin security.debian.org
 -10 https://deb.debian.org/debian buster-updates/main i386 Packages
     release o=Debian,a=stable-updates,n=buster-updates,l=Debian,c=main,b=i386
     origin deb.debian.org
 -10 https://deb.debian.org/debian buster-updates/main amd64 Packages
     release o=Debian,a=stable-updates,n=buster-updates,l=Debian,c=main,b=amd64
     origin deb.debian.org
 -10 https://deb.debian.org/debian buster/main i386 Packages
     release v=10.4,o=Debian,a=stable,n=buster,l=Debian,c=main,b=i386
     origin deb.debian.org
 -10 https://deb.debian.org/debian buster/main amd64 Packages
     release v=10.4,o=Debian,a=stable,n=buster,l=Debian,c=main,b=amd64
     origin deb.debian.org
 500 http://archive.canonical.com/ubuntu focal/partner i386 Packages
     release v=20.04,o=Canonical,a=focal,n=focal,l=Partner archive,c=partner,b=i386
     origin archive.canonical.com
 500 http://archive.canonical.com/ubuntu focal/partner amd64 Packages
     release v=20.04,o=Canonical,a=focal,n=focal,l=Partner archive,c=partner,b=amd64
     origin archive.canonical.com
 500 http://security.ubuntu.com/ubuntu focal-security/multiverse amd64 Packages
     release v=20.04,o=Ubuntu,a=focal-security,n=focal,l=Ubuntu,c=multiverse,b=amd64
     origin security.ubuntu.com
 500 http://security.ubuntu.com/ubuntu focal-security/universe i386 Packages
     release v=20.04,o=Ubuntu,a=focal-security,n=focal,l=Ubuntu,c=universe,b=i386
     origin security.ubuntu.com
 500 http://security.ubuntu.com/ubuntu focal-security/universe amd64 Packages
     release v=20.04,o=Ubuntu,a=focal-security,n=focal,l=Ubuntu,c=universe,b=amd64
     origin security.ubuntu.com
 500 http://security.ubuntu.com/ubuntu focal-security/restricted i386 Packages
     release v=20.04,o=Ubuntu,a=focal-security,n=focal,l=Ubuntu,c=restricted,b=i386
     origin security.ubuntu.com
 500 http://security.ubuntu.com/ubuntu focal-security/restricted amd64 Packages
     release v=20.04,o=Ubuntu,a=focal-security,n=focal,l=Ubuntu,c=restricted,b=amd64
     origin security.ubuntu.com
 500 http://security.ubuntu.com/ubuntu focal-security/main i386 Packages
     release v=20.04,o=Ubuntu,a=focal-security,n=focal,l=Ubuntu,c=main,b=i386
     origin security.ubuntu.com
 500 http://security.ubuntu.com/ubuntu focal-security/main amd64 Packages
     release v=20.04,o=Ubuntu,a=focal-security,n=focal,l=Ubuntu,c=main,b=amd64
     origin security.ubuntu.com
 100 http://archive.ubuntu.com/ubuntu focal-backports/universe i386 Packages
     release v=20.04,o=Ubuntu,a=focal-backports,n=focal,l=Ubuntu,c=universe,b=i386
     origin archive.ubuntu.com
 100 http://archive.ubuntu.com/ubuntu focal-backports/universe amd64 Packages
     release v=20.04,o=Ubuntu,a=focal-backports,n=focal,l=Ubuntu,c=universe,b=amd64
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal-updates/multiverse amd64 Packages
     release v=20.04,o=Ubuntu,a=focal-updates,n=focal,l=Ubuntu,c=multiverse,b=amd64
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal-updates/universe i386 Packages
     release v=20.04,o=Ubuntu,a=focal-updates,n=focal,l=Ubuntu,c=universe,b=i386
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal-updates/universe amd64 Packages
     release v=20.04,o=Ubuntu,a=focal-updates,n=focal,l=Ubuntu,c=universe,b=amd64
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal-updates/restricted i386 Packages
     release v=20.04,o=Ubuntu,a=focal-updates,n=focal,l=Ubuntu,c=restricted,b=i386
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal-updates/restricted amd64 Packages
     release v=20.04,o=Ubuntu,a=focal-updates,n=focal,l=Ubuntu,c=restricted,b=amd64
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal-updates/main i386 Packages
     release v=20.04,o=Ubuntu,a=focal-updates,n=focal,l=Ubuntu,c=main,b=i386
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages
     release v=20.04,o=Ubuntu,a=focal-updates,n=focal,l=Ubuntu,c=main,b=amd64
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal/multiverse i386 Packages
     release v=20.04,o=Ubuntu,a=focal,n=focal,l=Ubuntu,c=multiverse,b=i386
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal/multiverse amd64 Packages
     release v=20.04,o=Ubuntu,a=focal,n=focal,l=Ubuntu,c=multiverse,b=amd64
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal/universe i386 Packages
     release v=20.04,o=Ubuntu,a=focal,n=focal,l=Ubuntu,c=universe,b=i386
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal/universe amd64 Packages
     release v=20.04,o=Ubuntu,a=focal,n=focal,l=Ubuntu,c=universe,b=amd64
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal/restricted i386 Packages
     release v=20.04,o=Ubuntu,a=focal,n=focal,l=Ubuntu,c=restricted,b=i386
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal/restricted amd64 Packages
     release v=20.04,o=Ubuntu,a=focal,n=focal,l=Ubuntu,c=restricted,b=amd64
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal/main i386 Packages
     release v=20.04,o=Ubuntu,a=focal,n=focal,l=Ubuntu,c=main,b=i386
     origin archive.ubuntu.com
 500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages
     release v=20.04,o=Ubuntu,a=focal,n=focal,l=Ubuntu,c=main,b=amd64
     origin archive.ubuntu.com
 500 http://packages.linuxmint.com ulyana/backport i386 Packages
     release v=20,o=linuxmint,a=ulyana,n=ulyana,l=linuxmint,c=backport,b=i386
     origin packages.linuxmint.com
 500 http://packages.linuxmint.com ulyana/backport amd64 Packages
     release v=20,o=linuxmint,a=ulyana,n=ulyana,l=linuxmint,c=backport,b=amd64
     origin packages.linuxmint.com
 500 http://packages.linuxmint.com ulyana/import i386 Packages
     release v=20,o=linuxmint,a=ulyana,n=ulyana,l=linuxmint,c=import,b=i386
     origin packages.linuxmint.com
 500 http://packages.linuxmint.com ulyana/import amd64 Packages
     release v=20,o=linuxmint,a=ulyana,n=ulyana,l=linuxmint,c=import,b=amd64
     origin packages.linuxmint.com
 700 http://packages.linuxmint.com ulyana/upstream i386 Packages
     release v=20,o=linuxmint,a=ulyana,n=ulyana,l=linuxmint,c=upstream,b=i386
     origin packages.linuxmint.com
 700 http://packages.linuxmint.com ulyana/upstream amd64 Packages
     release v=20,o=linuxmint,a=ulyana,n=ulyana,l=linuxmint,c=upstream,b=amd64
     origin packages.linuxmint.com
 500 http://packages.linuxmint.com ulyana/main i386 Packages
     release v=20,o=linuxmint,a=ulyana,n=ulyana,l=linuxmint,c=main,b=i386
     origin packages.linuxmint.com
 500 http://packages.linuxmint.com ulyana/main amd64 Packages
     release v=20,o=linuxmint,a=ulyana,n=ulyana,l=linuxmint,c=main,b=amd64
     origin packages.linuxmint.com
 500 http://dl.google.com/linux/chrome/deb stable/main amd64 Packages
     release v=1.0,o=Google LLC,a=stable,n=stable,l=Google,c=main,b=amd64
     origin dl.google.com
Pinned packages:
     chromium-bsu -> 0.9.16.1-2 with priority -10
     chromium-driver -> 83.0.4103.116-1~deb10u2 with priority 700
     chromium-driver -> 80.0.3987.162-1~deb10u1 with priority 700
     chromium-l10n -> 83.0.4103.116-1~deb10u2 with priority 700
     chromium-l10n -> 80.0.3987.162-1~deb10u1 with priority 700
     snapd -> 2.45.1+20.04 with priority -10
     snapd -> 2.44.3+20.04 with priority -10
     snapd -> 2.37.4-1+b1 with priority -10
     libicu63 -> 63.1-6+deb10u1 with priority 1
     chromium-shell -> 83.0.4103.116-1~deb10u2 with priority 700
     chromium-shell -> 80.0.3987.162-1~deb10u1 with priority 700
     chromium -> 83.0.4103.116-1~deb10u2 with priority 700
     chromium -> 80.0.3987.162-1~deb10u1 with priority 700
     libjpeg62-turbo-dev -> 1:1.5.2-2+b1 with priority 1
     chromium-bsu-data -> 0.9.16.1-2 with priority -10
     libvpx5 -> 1.7.0-3+deb10u1 with priority 1
     chromium-sandbox -> 83.0.4103.116-1~deb10u2 with priority 700
     chromium-sandbox -> 80.0.3987.162-1~deb10u1 with priority 700
     chromium-common -> 83.0.4103.116-1~deb10u2 with priority 700
     chromium-common -> 80.0.3987.162-1~deb10u1 with priority 700
     chromium-tt-rss-notifier -> 0.5.2-2 with priority 700
     libevent-2.1-6 -> 2.1.8-stable-4 with priority 1
     chromium-lwn4chrome -> 1.0-3 with priority 700
     libjpeg62-turbo -> 1:1.5.2-2+b1 with priority 1
     chromium-ublock-origin -> 1.22.2+dfsg-1~deb10u1 with priority 700