It seems rhpkg mockbuild --addrepo does not work for RHEL 8.10 repos, when running a command like:
rhpkg mockbuild --addrepo
$ rhpkg mockbuild -- --addrepo=<internal Red Hat URL goes here>
I get a spew of errors:
Running transaction check No available modular metadata for modular package 'ruby-2.5.9-113.module+el8.10.0+22581+23fc9c9e.x86_64', it cannot be installed on the system No available modular metadata for modular package 'ruby-libs-2.5.9-113.module+el8.10.0+22581+23fc9c9e.x86_64', it cannot be installed on the system No available modular metadata for modular package 'rubygem-json-2.1.0-113.module+el8.10.0+22581+23fc9c9e.x86_64', it cannot be installed on the system No available modular metadata for modular package 'rubygem-openssl-2.1.2-113.module+el8.10.0+22581+23fc9c9e.x86_64', it cannot be installed on the system No available modular metadata for modular package 'rubygem-psych-3.0.2-113.module+el8.10.0+22581+23fc9c9e.x86_64', it cannot be installed on the system No available modular metadata for modular package 'rubygems-2.7.6.3-113.module+el8.10.0+22581+23fc9c9e.noarch', it cannot be installed on the system Error: No available modular metadata for modular package
Red Hat employees can find the URL to pass to addrepo and other instructions for reproducing here. This link also contains suggested workarounds; notably, it seems we need to pass module_hotfixes=1, which might require changes in mock.
module_hotfixes=1
(Using rhpkg mockbuild without --addrepo is notably not possible until this unrelated issue report gets fixed.)
rhpkg mockbuild