[jonathanpoulter]

How does a mono-repo company manage open sourcing a single part of their infrastructure if things are in one large repo? For example, if everything lived in one repo, how does Facebook manage open sourcing React? Or if I personally wanted to switch to one private mono-repo, how would I share individual projects easily?

[euyyn]

So open sourcing can mean three different things:

The bad one is just dumping snapshots of the code into a public repo every so often. You need to make sure your dependencies are open source, have tools that rewrite your code and build files accordingly, and put them in a staging directory for publishing.

The good one is developing that part publicly, and importing it periodically into your internal monorepo with the same (or similar) process to the one you use for importing any other third-party library.

There's also a hybrid approach which is to try and let internal developers use the internal tooling against the internal version of the code, and also external developers, with external tooling, against the public version. That one's harder, and you need a tool that does bidirectional syncing of change requests, commits, and issues.

[asp2insp]

We have an internal tool that allows us to mirror subdirectories of our monorepo into individual github repositories, and another tool that helps us sync our internal source code review tool with PRs etc.

[jonathanpoulter]

An internal tool which manages commits, between individual repos etc. does it not seem that this is a logical extension to git itself? A little like submodules, but being able to publish only parts of the sourcetree. Maybe it would be impossible to keep any consistency and leaking information from the rest of the tree.

[Blackthorn]

With difficulty.

No, seriously, that's the answer.

[computerex]

They have an internal mono-repo and public repos on GitHub that are mirrors of their mono-repo.