[umanwizard]

FWIW at least 95% (anecdotally) of Facebook’s main code is in two gigantic monorepos: fbsource and www. (The other major repos are for configuration-related stuff).

Last I heard there were plans to move www into fbsource.

There are certainly not random dependencies on public GitHub pages. Everything is versioned.

There is a mind boggling amount of custom tooling to make this work.

[humanrebar]

The versioned external dependencies work for systems that support semantic versioning. Some dynamic languages. Some C. Definitely nothing with a non-C ABI.

But "not working" looks like fixing an unknown number of bugs across the various subrepos. Because permanently forking upstream it never applying security patches isn't a good business model.