[seabrookmx]

For all the "big" Google projects they use a proprietary system called piper.

I think all their open-source stuff (Angular, GoLang, Android) uses git (and sometimes Gerrit).

Although given Google's scale, I'm sure there's some teams/projects that use Mercurial.

[ngoldbaum]

In fact, developers are allowed to use whichever VCS tool they want on their local machine (or on the online coding in the cloud CitC environment). Some opt to use hg. The canonical repo is in piper though, so the hg commits or git commits get converted before they land.

[kardianos]

Gerrit is a review server that uses git. In fact, Gerrit now stores the majority of information in git itself for all the information it uses.

So for Google external projects, they use git.

> Although given Google's scale, I'm sure there's some teams/projects that use Mercurial.

I doubt it. Their tooling is probably pretty specific, and now that code.google.com has shut down, they probably don't have any review servers that support it.

[harveynick]

Yes and no. The answer is actually quite complicated... and I have no idea if I'm allowed to talk about it publically or not.

[harveynick]

The most recent reason public reference I can find to this is from 2016: https://cacm.acm.org/magazines/2016/7/204032-why-google-stor...

Here's the money quote:

"The team is also pursuing an experimental effort with Mercurial an open source DVCS similar to Git. The goal is to add scalability features to the Mercurial client so it can efficiently support a codebase the size of Google's. This would provide Google's developers with an alternative of using popular DVCS-style workflows in conjunction with the central repository. This effort is in collaboration with the open source Mercurial community, including contributors from other companies that value the monolithic source model."

Project that forward logically by two years.

[ksec]

Not sure why I got heavily downvotes. This above was the pieces of information that got me to think they were all on hg. So judging from the comment I stand corrected.

[harveynick]

Your assumption was pretty reasonable based on the public information. Honestly I’d love to talk about how Google does source control/ code review etc. because it’s actually pretty interesting at this point. You know... for some values of interesting.

[falsedan]

Then don't waste peoples time with vacuous comments.

[harveynick]

Ironic reply.

Sincere apologies if you can't derive any information from my comment, but that doesn't mean there isn't any there.

[falsedan]

The only information is “google employs me”.

[harveynick]

Does Google use hg? “Yes and no. It’s complicated.” You can’t read anything into that?

[joatmon-snoo]

Everything speaks Piper.

Devs can use the mercurial/git clients mentioned in the paper linked by harveynick.

[seabrookmx]

> Gerrit is a review server that uses git

Yup! I use Gerrit at my company and share Administration duties with our Devops team.

I know Android uses Gerrit I just wasn't sure if Angular and co. did which is why I worded it a bit more vaguely.

[pjmlp]

Go started on Mercurial and then eventually moved into Git.

[jordigh]

And they like neither. They really want a versioned filesystem.

[dilap]

That's interesting. Do you have more details / refs?

[jordigh]

I understand this was private communication from Rob and Russ.

[dilap]

well dang! :-)