> They decided to go with mercurial because it was possible to monkey patch
The ability to extend, swap and replace deep into the stack was always a core component of Mercurial, hence having to enable extensions for things many users would consider core features e.g. terminal colors or graph log
Facebook didn't hack around like monkeys, they built extensions. And when they could not do it as extensions, they upstreamed improvements to the core.
The alternative would have been to fork the codebase entirely.
Monkey patching the internals would have been significantly less maintainable: having used it as a library, I can tell you that none of the internal stuff is considered stable and pretty major components will change between point releases (I was using the diff-parsing and patch-application routines for something else, the API changed basically every minor release, forking would at least give you a heads-up conflict when upstream changed, monkey-patching would either blow up at runtime or not go through the patch anymore)
> They're now talking about implementing parts in rust, which, ironically, would have prevented them from doing what they originally chose mercurial for.
The ability to extend, swap and replace deep into the stack was always a core component of Mercurial, hence having to enable extensions for things many users would consider core features e.g. terminal colors or graph log
Facebook didn't hack around like monkeys, they built extensions. And when they could not do it as extensions, they upstreamed improvements to the core.
The alternative would have been to fork the codebase entirely.
Monkey patching the internals would have been significantly less maintainable: having used it as a library, I can tell you that none of the internal stuff is considered stable and pretty major components will change between point releases (I was using the diff-parsing and patch-application routines for something else, the API changed basically every minor release, forking would at least give you a heads-up conflict when upstream changed, monkey-patching would either blow up at runtime or not go through the patch anymore)
> They're now talking about implementing parts in rust, which, ironically, would have prevented them from doing what they originally chose mercurial for.
No.