Description of problem:

Attempting to upgrade from F30 to F31 via dnf system-upgrade fails the transaction due to the presence of locally built, no-repo RPMs, in a non-obvious way:

2019-11-11T07:45:15Z INFO --- logging initialized ---
2019-11-11T07:45:15Z DDEBUG timer: config: 44 ms
2019-11-11T07:45:15Z DEBUG Loaded plugins: builddep, changelog, config-manager, copr, debug, debuginfo-install, download
, generate_completion_cache, needs-restarting, playground, repoclosure, repodiff, repograph, repomanage, reposync, syste
m-upgrade
2019-11-11T07:45:15Z DEBUG DNF version: 4.2.11
2019-11-11T07:45:15Z DDEBUG Command: dnf system-upgrade upgrade
2019-11-11T07:45:15Z DDEBUG Installroot: /
2019-11-11T07:45:15Z DDEBUG Releasever: 30
2019-11-11T07:45:15Z DEBUG cachedir: /var/cache/dnf
2019-11-11T07:45:15Z DDEBUG Base command: system-upgrade
2019-11-11T07:45:15Z DDEBUG Extra commands: ['system-upgrade', 'upgrade']
2019-11-11T07:45:15Z DEBUG Unknown configuration value: failovermethod=priority in /etc/yum.repos.d/fedora-updates-modul
ar.repo; Configuration: OptionBinding with id "failovermethod" does not exist
2019-11-11T07:45:15Z DEBUG Unknown configuration value: failovermethod=priority in /etc/yum.repos.d/fedora-updates-modul
ar.repo; Configuration: OptionBinding with id "failovermethod" does not exist
2019-11-11T07:45:15Z DEBUG Unknown configuration value: failovermethod=priority in /etc/yum.repos.d/fedora-updates-modular.repo; Configuration: OptionBinding with id "failovermethod" does not exist
2019-11-11T07:45:15Z DEBUG repo: using cache for: fedora-modular
2019-11-11T07:45:16Z DEBUG fedora-modular: using metadata from Thu 24 Oct 2019 09:48:21 PM EDT.
2019-11-11T07:45:16Z DEBUG repo: using cache for: updates-modular
2019-11-11T07:45:16Z DEBUG updates-modular: using metadata from Sat 09 Nov 2019 09:26:21 PM EST.
2019-11-11T07:45:16Z DEBUG repo: using cache for: updates
2019-11-11T07:45:16Z DEBUG updates: using metadata from Sat 09 Nov 2019 03:48:37 PM EST.
2019-11-11T07:45:16Z DEBUG repo: using cache for: fedora
2019-11-11T07:45:17Z DEBUG fedora: using metadata from Thu 24 Oct 2019 09:48:20 PM EDT.
2019-11-11T07:45:18Z DDEBUG timer: sack setup: 2541 ms
2019-11-11T07:45:18Z DEBUG Completion plugin: Generating completion cache...
2019-11-11T07:45:19Z DEBUG --> Starting dependency resolution
2019-11-11T07:45:19Z DEBUG --> Finding unneeded leftover dependencies
2019-11-11T07:45:20Z DEBUG --> Finished dependency resolution
2019-11-11T07:45:20Z DDEBUG timer: depsolve: 774 ms
2019-11-11T07:45:20Z SUBDEBUG
Traceback (most recent call last):
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 122, in cli_run
    ret = resolving(cli, base)
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 158, in resolving
    base.resolve(cli.demands.allow_erasing)
  File "/usr/lib/python3.7/site-packages/dnf/base.py", line 766, in resolve
    raise exc
dnf.exceptions.DepsolveError:
 Problem: The operation would result in removing the following protected packages: kernel-core
2019-11-11T07:45:20Z CRITICAL Error:
 Problem: The operation would result in removing the following protected packages: kernel-core
2019-11-11T07:45:20Z INFO (try to add '--skip-broken' to skip uninstallable packages)
2019-11-11T07:45:20Z DDEBUG Cleaning up.


Actual results:
dnf system-upgrade fails, boots back into F30


Expected results:
dnf system-upgrade succeeds, leaving local RPMs installed


Additional info:
This is possibly related to bug 1764169, but the exact circumstances and resulting error are different.  Manually removing the local F30 package, forcing system-ugprade to build a new transaction, rebooting into the upgrade, and then reinstalling the same F30 package is enough to work around the issue -- but also makes it clear that there is no actual dependency issue with the package in question on F31, thus no obvious reason why the transaction failed during system-upgrade.