Analysis:

Old code: ( 6.12 and before )

      def host_latest_applicable_rpm_version(host, package)
        host.applicable_rpms.where(name: package).order(:version_sortable).limit(1).pluck(:nvra).first
      end


New Code: ( > = 6.13 )

      def host_latest_applicable_rpm_version(host, package)
        ::Katello::Rpm.latest(host.applicable_rpms.where(name: package)).first.nvra
      end

Test of new code:

irb(main):004:0> host = Host.second
=> #<Host::Managed id: 2, name: "dhcp130-139.example.com", last_compile: "2023-05-09 09:35:24.000000000 +0000", last_rep...

irb(main):007:0> package = 'kernel'
=> "kernel"


irb(main):008:0> ::Katello::Rpm.latest(host.applicable_rpms.where(name: package)).first.nvra
Traceback (most recent call last):
        2: from lib/tasks/console.rake:5:in `block in <top (required)>'
        1: from (irb):8
NoMethodError (undefined method `nvra' for nil:NilClass)

irb(main):009:0> ::Katello::Rpm.latest(host.applicable_rpms.where(name: package)).first
=> nil

irb(main):011:0> ::Katello::Rpm.latest(host.applicable_rpms.where(name: package)).first.try(:nvra)
=> nil

Basically, If the host.applicable_rpms have no results or host.applicable_rpms.where(name: package)).first have no results, we run into this and if we use the try method , that helps to get past the issue


So following, fixes the issue:

diff --git a/app/lib/katello/concerns/base_template_scope_extensions.rb b/app/lib/katello/concerns/base_template_scope_extensions.rb
index 873c7bf..6cfe8f8 100644
--- a/app/lib/katello/concerns/base_template_scope_extensions.rb
@@ -161,7 +161,7 @@ module Katello
         returns String, desc: 'Package version'
       end
       def host_latest_applicable_rpm_version(host, package)
-        ::Katello::Rpm.latest(host.applicable_rpms.where(name: package)).first.nvra
+        ::Katello::Rpm.latest(host.applicable_rpms.where(name: package)).first.try(:nvra)
       end
 
       apipie :method, 'Loads Pool objects' do

I am guessing this also fixes the issue instead of what I tried in Coment 1 

https://github.com/Katello/katello/pull/10497/files#diff-97789298ab25018d9ce64de6b68fa6cfcc0b066e351c4156ebd5d70176022281R182-R186

      def host_latest_applicable_rpm_version(host, package)
        return [] if host.content_facet.nil?
        applicable = ::Katello::Rpm.latest(host.applicable_rpms.where(name: package))
        applicable.present? ? applicable.first.nvra : []
      end


This change is scheduled to be part of Satellite 6.14 along with the inclusion Installable ERRATA template 

But perhaps we should consider this or part of the fix for 6.13.z or else many customers could end up hitting this issue when a host would not have any applicable rpms 


CC'ing Ian from the Katello team

We can use the same code from the "Installable ERRATA template" RFE but we'll need something that only applies to the 6.13 / Katello 4.7 branches.

To complete this issue I'd recommend making a Katello 4.7 issue upstream and then create the PR against the Katello 4.7 branch only. That should ensure that, next time there's a Katello 4.8 release, it'll be marked as a cherry-pick.

Created redmine issue https://projects.theforeman.org/issues/36486 from this bug

Moving this bug to POST for triage into Satellite since the upstream issue https://projects.theforeman.org/issues/36486 has been resolved.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Important: Satellite 6.14 security and bug fix update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2023:6818