yarn global upgrade complains about outdated lockfile

[awwright]

I run into a problem when trying to upgrade my global packages. To upgrade them, I run yarn global upgrade --latest, but it just reports this error:

warning package.json: No license field
info No lockfile found.
error Outdated lockfile. Please run `yarn install` and try again.
info Visit https://yarnpkg.com/en/docs/cli/global for documentation about this command.

This is a very odd error, I'm not sure why global packages would ever need a lockfile. I just want the latest versions of packages, there is no reason a lockfile should play into this at all.

I can't find any documentation about this. A Web search for "yarn outdated lockfile" lists #6320 as the top result. The workaround there doesn't work, because yarn install won't install one of my packages due to a build error. This may be a bug in one of the packages... which I can't upgrade away from because I can't run yarn global upgrade.