Software Engineering at Google
books.google.com
books.google.com
For example the book has a section called "How Code Review Works At Google." And it goes on to describe strictly the google3 process. But Chrome, ChromeOS, GoogleX, others have different processes. If Google has a proven model, why do so many of its projects deviate from it?
During my time there, the Android team was recruiting internally, advertising "come work on Android, we don't require Readability." It was seen as an internal competitive advantage to reject these processes! What does that say about how they are perceived internally?
I speculate that Android and Chrome and others have distinct processes for a good reason, and that the book is unknowingly slanted towards web-service style engineering.
It certainly says something about how the Android org was perceived internally during most of the time I was there (2011-2018).
I assume from capitalisation and context that Readability is some very specific and very strict set of rules? I’m curious what would be there that would be so offputting...
It used to be that you had to do a "readability review" which was a large change that you developed specifically to gain readability in some language. A style reviewer would approve it after (usually) many rounds of comments, and then thereafter you had C++ readability forever.
More recently some language teams have adopted incremental readability. In this process you add a language reviewer to all of your changes, and after you demonstrate that you know what you are doing, they will grant you readability. I think the Go team was the first group to adopt incremental readability, but it spread to other languages.
This process is off-putting to people who want to join Google but not be acculturated to their language style rules. There's a surprising number of these people. In mainline Google these people simply will not get bonuses, raises, and promotions. In defective organizations like Android they just discard Google code quality standards and it shows.
- is an Owner of the code
- has Readability in the language of the code
- is not you
If you are an owner and have readability, you just need someone who isn't you to sign off on it. If you don't have ownership or readability you need to get someone who has those things to sign off. If you can find someone who has both, great. Otherwise you'll need two people.
Having readability in a language can make you pretty desirable, particularly if it's in a language that your team doesn't often use. It's hard to get, and it takes time. My team is pure Java, but once in a long while we check in Python scripts. Most people have Java readability, but I'm one of two people on the team with Python, which makes me more valuable to the team.
It's really hard to get someone who isn't on your team to give you a readability review.
I'd like to acknowledge the brilliance of people who name their code files "foo.javascript" to avoid having to get JS readability.
Titus is both on the C++ standards committee and did a ton of work working on C++ style and core libraries when I was there.
Hyrum was the king of large-scale refactoring and had (IIRC) more than billion lines of code changed and millions of CLs submitted across all of google by the time I left.
If those quick talks were any indication, there will be a lot of value in this book for experienced developers.
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I feel like it's more geared for people that have worked in software for at least a decade and need to break bottlenecks in their org. Either as guidance, or as a sales pitch to show executive management "See Google does it."
Google has custom tooling, custom kernels, custom hardware, etc and legions of support at every layer of the stack. Complexity is not eschewed but it is rather embraced if it means some slight improvement in utilization or better looking latency distribution.
Those goals are not sustainable in normal businesses, even tech ones.
Google places very little emphasis on things like code readability and testability because it’s easy for them to do rewrites or just run tests on 1 million cores to shake out race conditions and locks.
Read this for entertainment but don’t try to blindly apply it to your work environment. Most of it will make you a bad engineer for non-FAANG envs.
Why do you say this? I've seen the opposite.
I can't submit untested code or code that doesn't have "readability" approval. It's certainly not perfect but testability is a huge part of any project I've worked on.
Also, tested code is not the same thing as “testable” code. Mock and monkey patching can very easily give you 100% coverage of untestable code with garbage tests.
This doesn't mean it leads to complex code.
The Google cpp style guide[0], for example, tries at length to keep code simple and stresses that even in C++, you should prefer simple things unless the performance benefits (of, say, nontrivial ownership) are provably necessary:
> The performance costs of value semantics are often overestimated, so the performance benefits of ownership transfer might not justify the readability and complexity costs.
> This doesn't mean it leads to complex code.
It does mean that it’s a completely subjective thing coming from other people in the very same culture of which I’m being critical. It’s like someone claiming the Chinese government isn’t authoritarian because Chinese citizens have slapped on the “non-authoritarian” label.
And the comment about readability and testability is so far different from my experience that I have to wonder where the poster is getting their information. Google code reviews have to be among the most nit-picky I've ever seen in a 30+ year career, with serious attention to detail all the way down to punctuation in comments.
Seriously, code review on punctuation in a comment is not good in any scenario and it speaks nothing to the legibility of the code itself. If anything, it might mean the code is unreadable and the reviewer is too embarrassed to point out that they can’t follow it.
While yes, nit-picky review could mean the reviewer doesn't understand the big picture, an LGTM with no comments at all is more likely to be indicative of missing something.
What you really mean is that nit-picky reviews that don't pick up on actual logic or functionality issues are a smell. Which is true, but isn't usually the case at Google[0]. The chapter on teamwork covers some relevant concepts (like psychological safety).
[0]: https://testing.googleblog.com/2018/05/code-health-understan...
You seem to be assuming, without prompt, that nit-picking punctuation comes at the expense of a thorough overall review.
Code review on punctuation is absolutely an important part of readability. Consistency makes understanding and scanning (for human readability) and potentially parsing and modifying (for machine readability) much easier.
As someone who both reviews a lot of code and reads a lot of code, consistent documentation with good grammar and punctuation is enormously helpful.
People who focus on punctuation do so at the expense of everything else, sure. But people who give thorough reviews give thorough reviews, including nitpicky comments.
I've given and received thousands of reviews at Google (in multiple languages, across multiple teams), and can say that my experience has been fairly consistent: code review is high quality and detail oriented, including, but not at all limited to, small things like grammar and comment formatting.
> But people who give thorough reviews give thorough reviews
Ok.
> including nitpicky comments.
Disagree. Pointing out that someone forgot to capitalize an initialism in a comment is not thorough, it’s a time suck. A thorough and competent reviewer will realize it doesn’t matter and will know not to distract the CL owner will such irrelevant trash.
Sure, there is an a small section of the Venn diagram that leaves good review comments and sprinkles in “nit:” turds, but that group is much smaller than both the fully incompetent nit-pick group and the competent reviewer group.
Seriously, unless a code comment is illegible or it’s being compiled into user-facing docs, it’s absolutely useless to leave something like “nit: it’s TCP, not tcp”.
I think you're describing style errors, not grammar errors. For example, the Google style guide says that (certain) comments should be complete sentences. Asking people to use good grammar (and capitalize/punctuate) those sentences as though they were documentation (because they are!) is valuable for reviewers.
I say this as someone who, when reading unfamiliar code, is able to understand it more readily if the inline documentation is easy to read. "tcp" vs "TCP" doesn't impact that, but other grammatical nits absolutely due.
The entire thread (not started by me) is about nit-picking punctuation and now you’re trying to explain to me that I’m describing style errors. So what? It’s useless feedback regardless of which chapter in the Holy Google Docs covers it.
> Asking people to use good grammar (and capitalize/punctuate) those sentences as though they were documentation (because they are!) is valuable for reviewers.
Right, it’s valuable for the reviewers because it makes it seem like they provided feedback when they have nothing of substance to add. It’s not valuable for the author though nor is it realistically valuable to future people reading the code in question.
>I say this as someone who, when reading unfamiliar code, is able to understand it more readily if the inline documentation is easy to read.
I think maybe you don’t know what “nitpick” means. https://www.dictionary.com/browse/nitpick
If it has a meaningful impact on the ability to read it, it’s not a nitpick.
If the comments aren't important enough to spend care and thought on, they should be deleted.
> If it has a meaningful impact on the ability to read it, it’s not a nitpick.
This is boring semantics. Given what you describe as nitpicks, we draw the line of meaningful impact on readability in different places. So I'm claiming that some of the things you describe as nitpicks in fact aren't.
The closest I've seen to this is comments of the form "can you reformat this" or "this doesn't match the rest of the file". Google's style guides have fairly strong guidance on formatting, so there's usually a "right" way (enforced by a linter), and if not, then usually you defer to the existing style in the module.
I would agree with linting or just deferring to existing style, but in truth I care little about this, it's just not significant to me (yet others seem to overvalue it, to the point of talking exclusively about this).
It's actually nice. I disagree with some of the rules and would like them to change. I think that if your if-block has a single statement and there's no else, and it all fits in a line then it's fine to inline it.
if (theAnswerIsKnown) return theAnswer;
Edit: To be clear, I might be right, and this might be better, but I'm "wrong" in the sense that it's not linter compliant.
Do you mean 'wrong' in the sense of 'wrong according to the rules enforced by the linter' or 'wrong philosophically' ? If it's the latter, how is that wrong and is not even a subject for debate?
This is an honest question, I guess I just don't see how something like this can "just" be wrong (to me it's irrelevant and not worth the ink used to write such statements in code reviews... though I'm playing devil's advocate here obviously :-) ).
PS: of course if pre-submit checks enforce the rules, then as you said it becomes a non-issue. I have been in environments where there are no such tool-enforced checks, yet people comment on it endlessly, routinely blocking code reviews for whitespace issues...
This is complete nonsense. Google's code review and testing and reliability practices are better and more sensible than most big and small companies I have worked for and heard about.
The biggest proprietary sink for most people is stuff like the build system/tooling/etc. Not many people have to be in a role where you're micro-optimizing something. They certainly exist, but not in the numbers some people on here seem to think.