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I have seen presentations mentioning google development done as a single monolothic repository

http://www.infoq.com/presentations/Development-at-Google

⬐ tonfa

This monolithic repo isn't a git repo.

⬐ spiffytech

Correct. See https://news.ycombinator.com/item?id=7020859

No, literally the entire codebase for all of their products is in one Perforce repo. Ashish Kumar, manager of the Engineering Tools team, mentions it in this presentation: http://www.infoq.com/presentations/Development-at-Google

⬐ sek

Very interesting, thank you.

⬐ rachelbythebay

The kernel? Android? Some other spooky stuff involving the pest control guy who's holding a big rubber mallet when you fail a unit test?

Are you sure about that?

⬐ nostrademons

Kernel/Android/Chrome/basically anything open-source is different. If the code is going to be open-sourced, it can't have dependencies on proprietary code anyway.

⬐ rachelbythebay

Right, so "literally the entire codebase for all their products" is incorrect. Thanks.

⬐ amalter

Ah,rachelbythebay, you caught him for being "technically incorrect". Which, depending on how you look at it, is either the best or worst kind of correctness.

⬐ jrockway

The open-source stuff is a rounding error. Think about all the Google products; Search, Google+, Gmail, Groups, Translate, Maps, Docs, Calendar, Checkout, Wallet, Voice, ... those are all in one repository. (Not to mention all the libraries and internal tools; those are all in there too.)

⬐ nostrademons

To be fair, Android and Chrome are pretty huge projects. I know the numbers (though I don't think I can share them outside of Google), and while they're nowhere close to being a big part of the total, they're also big enough to not be considered a rounding error.

⬐ lukeholder

would they merge in head to their build before committing for code review?

⬐ lukesandberg

Sorry misread the original post.

Before a code review you don't have to do a sync but its pretty common to sync frequently. I sync constantly as im developing because it's so easy. Occasionally i see reviews where i can tell that the person hasn't sync'd in a while and if i think it matters ill ask them to sync. This usually doesn't happen though

⬐ scorpion032

That is, half of the files in their perforce are "touched in the last 30 days".

I was there, live in this presentation, more than a year ago, at Hyderabad and got this clarification from the speaker.

⬐ nikcub

very big difference to what the headline says, which was never going to be correct.

⬐ markokocic

Much more informative that the title itself. Touching file and changing maybe one line is not a big deal, but rewriting half of the source code base every months is.

⬐ zaph0d

The title is a direct quote from the Google Engg. Tools blog post which was on HN recently - http://google-engtools.blogspot.com/2011/12/bug-prediction-a...

⬐ scorpion032

True. Half the code can be anything. Half the characters in source, half the lines (Which seem more plausible since version control systems deal with line as a unit) or half of the files or even half the binaries. I'm just clarifying based on my own clarification, which half it is.

I don't think, this is any surprising at all. I believe the statistics would remain the same, for many companies.

⬐ admp

Some things I did not expect:

- 50% of the codebase changes every month;

- Single code tree;

- All of the development happens in HEAD (ditto for dependencies);

- It seems to be (relatively) usual to touch multiple components in a single changeset.

And all of this in the first 10 minutes.

Edit: formatting.