This is timely, as I used submodules years ago and got very confused with them. But now I have an Ask HN: I'm building a ruby gem (package) that will be share

This is timely, as I used submodules years ago and got very confused with them. But now I have an Ask HN: I'm building a ruby gem (package) that will be shared across a few of my applications. The apps are separate and proprietary, but I want to open source the gem, so a monorepo doesn't fit. When the gem is stable, I can just publish it and then reference it in my Gemfile like any other gem - rebundling every time there's a new release. But at the moment, I'm actively developing the gem and making frequent changes to the API - so I want to reference it directly from the container app and edit both together as different edge cases arise. The standard Ruby on Rails way to do this is to stick it in /lib or /vendor - then work on it and once done, extract it and publish the gem. But I'm working on several apps that share this gem and will all influence how it works. So I don't want multiple vendored copies scattered across different source trees. And I don't want to be rebundling the app every time I make a minor change to the gem - so referencing the git repo is out. On paper a submodule sounds like the perfect solution - main app is a repo, with a submodule repo in vendor. I can make changes to both, then push them separately to their own repos. If I start working on app 2, I just fetch the submodule to get the latest version of the gem without having to rebundle everything. As it's just me working on this set of code at the moment, are submodules a good fit?