- Facebook does not use Git due to scale issues with their large monorepo, instead opting for Mercurial.
- Mercurial may be a better option for large monorepos, but Git has made improvements to support them better.
- Despite some drawbacks, Git usage remains dominant with 93.87% share, due to familiarity, additional tools, and industry trends.
Facebook uses Mercurial, but when people praise their developer tooling it’s not just that. They’re using their CLI which is built on top of Mercurial but cleans up its errors and commands further, it’s all running on their own virtual filesystem (EdenFS), their dev testing in a customized version of chromium, and they sync code using their own in-house equivalent of GitHub, and all of it connects super nicely into their own customized version of VS Codium.
The source control was so smooth and pleasant that it convinced me that git isn’t the be all end all, and the general developer focus was super nice, but some of that tooling was pretty janky, poorly documented, and you had no stack overflow to fall back on. And some of it (like EdenFS), really felt like it was the duct tape holding that overloaded monorepo together (complete with all the jankiness of a duct tape solution).
And kinda horrifying. If something goes wrong, no Google, it’s straight to IT
There’s probably specific ticket queues and wiki/doc spaces for each support team.
Problem with an app? Send it to the internal dev/support team. Then if needed it gets routed.
And some good management. Probably not a common opinion around here, but my company is not a tenth of that size, with a hundredth the number of devs, yet different teams still end up copy pasting libraries. Because it’s faster than convincing management DevOps is important.
The inhouse tooling from the massive tech companies is very cool but I always wonder how that impacts transferrable skills. I work in a much smaller shop but intentionally make tech decisions that will give our engineers a highly transferrable skill set. If someone wants to leave it should be easy to bring their knowledge to bear elsewhere.
Speaking from my own experience and a few other seniors I work with, you try to recreate solutions you like at those smaller shops. It may not be identical, but you know what’s possible.
I came into a company that didn’t have a system to manage errors. At my old job, errors would get grouped automatically and work can be prioritized through the groupings. The new company only handled errors when they saw it, by word of mouth.
Immediately went to work setting up a similar system.
There’s also a whole industry of ex-Googlers reimplementing Google tooling as SaaS services to sell to other ex-Googlers at other companies.
There’s even a lookup table: https://github.com/jhuangtw/xg2xg
(some of those are open source projects, some are SaaS services)
The inhouse tooling from the massive tech companies is very cool
I agree. I personally know nothing about tooling like this but I went through the tooling used at rockstar for example GTA V and it was very cool to how much they have automated and made tools easier to use.
Made easier to use like in when their codebase was leaked and no one had successfully built a game from it?
in-house tools often encourage making a mess heavily reliant on those tools or working around their limitations, in my experience
I’m pleased to report that git has made significant strides, and git submodule can now be easily used to achieve a mono-repo-like level of painful jankiness.
Mercurial does have a few things going for it, though for most use-cases it’s behind Git in almost all metrics.
I really do like the fact that it keeps a commit number counter, it’s a lot easier to know if “commit 405572” is newer than “commit 405488” after all, instead of Git’s “commit ea43f56” vs “commit ab446f1”. (Though Git does have the describe format, which helps somewhat in this regard. E.g. “0.95b-4204-g1e97859fb” being the 4204th commit after tag 0.95b)
I suspect rebasing makes sequential commit IDs not really work in practice.
Rebasing updates the commit ids. It’s fine. Commit IDs are only local anyway.
One thing that makes mercurial better for rebase based flows is obsolescence markers. The old version of the commits still exist after a rebases and are marked as being made obsolete by the new commits. This means somebody you’ve shared those old commits with isn’t left in hyperspace when they fetch your new commits. There’s history about what happened being shared.
That’s exactly the same in git. The old commits are still there, they just don’t show up in git log because nothing points to them.
And google uses Piper to do the same thing
And they’re delivering a terrible product.
