See https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/MCH2VQHJQCSSTV7OIQ67JPIS6JMU2DNS/


When I try to init a rawhide mock, I get:

$ mock -r fedora-rawhide-x86_64 init
...
ERROR: Command failed: 
 # /usr/bin/dnf --installroot /var/lib/mock/fedora-rawhide-x86_64/root/ --releasever 31 --disableplugin=local --setopt=deltarpm=False install @buildsys-build
Modular dependency problems:

 Problem 1: conflicting requests
  - nothing provides module(platform:f30) needed by module stratis:1:20181215204600:a5b0195c-0.x86_64
 Problem 2: conflicting requests
  - nothing provides module(platform:f30) needed by module standard-test-roles:3.0:3020190214144451:a5b0195c-0.x86_64
 Problem 3: conflicting requests
  - nothing provides module(platform:f30) needed by module ripgrep:latest:3020190214090003:a5b0195c-0.x86_64
 Problem 4: conflicting requests
  - nothing provides module(platform:f30) needed by module ninja:latest:3020190131012415:a5b0195c-0.x86_64
 Problem 5: conflicting requests
  - nothing provides module(platform:f30) needed by module meson:latest:3020190123223713:36245242-0.x86_64
 Problem 6: conflicting requests
  - nothing provides module(platform:f30) needed by module libgit2:0.27:3020190128145600:a5b0195c-0.x86_64
 Problem 7: conflicting requests
  - nothing provides module(platform:f30) needed by module gimp:2.10:20181223154246:a5b0195c-0.x86_64
 Problem 8: conflicting requests
  - nothing provides module(platform:f30) needed by module fish:3:3020190216163513:602da195-0.x86_64
 Problem 9: conflicting requests
  - nothing provides module(platform:f30) needed by module exa:latest:3020190214120734:e50d0d19-0.x86_64
 Problem 10: conflicting requests
  - nothing provides module(platform:f30) needed by module dwm:6.1:3020190213215420:a5b0195c-0.x86_64
 Problem 11: conflicting requests
  - nothing provides module(platform:f30) needed by module bat:latest:3020190214090936:e50d0d19-0.x86_64
 Problem 12: conflicting requests
  - nothing provides module(platform:f30) needed by module avocado:stable:3020190213205848:a5b0195c-0.x86_64
Detection of Platform Module failed: Cannot open file: /var/lib/mock/fedora-rawhide-x86_64/root/etc/os-release
Traceback (most recent call last):
  File "/usr/lib/python3.7/site-packages/dnf/cli/commands/install.py", line 86, in run
    module_base.install(self.opts.grp_specs, strict=self.base.conf.strict)
  File "/usr/lib/python3.7/site-packages/dnf/module/module_base.py", line 129, in install
    module_debsolv_errors=solver_errors)
dnf.exceptions.MarkingErrors: Problems in request:
missing groups or modules: buildsys-build
Modular dependency problems with Defaults:

 Problem 1: conflicting requests
  - nothing provides module(platform:f30) needed by module avocado:stable:3020190213205848:a5b0195c-0.x86_64
 Problem 2: conflicting requests
  - nothing provides module(platform:f30) needed by module bat:latest:3020190214090936:e50d0d19-0.x86_64
 Problem 3: conflicting requests
  - nothing provides module(platform:f30) needed by module dwm:6.1:3020190213215420:a5b0195c-0.x86_64
 Problem 4: conflicting requests
  - nothing provides module(platform:f30) needed by module exa:latest:3020190214120734:e50d0d19-0.x86_64
 Problem 5: conflicting requests
  - nothing provides module(platform:f30) needed by module fish:3:3020190216163513:602da195-0.x86_64
 Problem 6: conflicting requests
  - nothing provides module(platform:f30) needed by module gimp:2.10:20181223154246:a5b0195c-0.x86_64
 Problem 7: conflicting requests
  - nothing provides module(platform:f30) needed by module libgit2:0.27:3020190128145600:a5b0195c-0.x86_64
 Problem 8: conflicting requests
  - nothing provides module(platform:f30) needed by module meson:latest:3020190123223713:36245242-0.x86_64
 Problem 9: conflicting requests
  - nothing provides module(platform:f30) needed by module ninja:latest:3020190131012415:a5b0195c-0.x86_64
 Problem 10: conflicting requests
  - nothing provides module(platform:f30) needed by module ripgrep:latest:3020190214090003:a5b0195c-0.x86_64
 Problem 11: conflicting requests
  - nothing provides module(platform:f30) needed by module standard-test-roles:3.0:3020190214144451:a5b0195c-0.x86_64
 Problem 12: conflicting requests
  - nothing provides module(platform:f30) needed by module stratis:1:20181215204600:a5b0195c-0.x86_64

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/dnf", line 58, in <module>
    main.user_main(sys.argv[1:], exit_code=True)
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 193, in user_main
    errcode = main(args)
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 64, in main
    return _main(base, args, cli_class, option_parser_class)
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 99, in _main
    return cli_run(cli, base)
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 115, in cli_run
    cli.run()
  File "/usr/lib/python3.7/site-packages/dnf/cli/cli.py", line 1108, in run
    return self.command.run()
  File "/usr/lib/python3.7/site-packages/dnf/cli/commands/install.py", line 97, in run
    module_debsolv_errors))
  File "/usr/lib/python3.7/site-packages/dnf/module/module_base.py", line 604, in format_modular_solver_errors
    msg = dnf.util._format_resolve_problems(errors)
  File "/usr/lib/python3.7/site-packages/dnf/util.py", line 384, in _format_resolve_problems
    msg += "\n  - ".join(rs)
TypeError: sequence item 0: expected str instance, list found


mock-1.4.14-1.fc29.noarch
mock-core-configs-30.1-1.fc29.noarch
dnf-4.1.0-1.fc29.noarch