在上一篇文章中提到过，我已经不在Google工作了。我还没有想清楚应该去哪里—有两三个非常好的工作机会摆在我面前。因为在这段做决定时间里，我不再受雇于任何人，我想可以写一些专业性的东西，一些很有趣，但也会在同事和管理工作中导致关系紧张的东西。
As I alluded to in my last post (which I will be correcting shortly), I no longer work for Google. I still haven't decided quite where I'm going to wind up - I've got a couple of excellent offers to choose between. But in the interim, since I'm not technically employed by anyone, I thought I'd do a bit of writing about some professional things that are interesting, but that might have caused tension with coworkers or management.
Google是一个非常优秀的公司。他们做出了很多令人称赞的东西—既是公司外部，人们可以看到的东西，也是公司内部。有一些在公司内部并不属于保密的事情，在外部并没有给予足够广泛的讨论。这就是我今天要说的。
Google is a really cool company. And they've done some really amazing things - both outside the company, where users can see it, and inside the company. There are a couple of things about the inside that aren't confidential, but which also haven't been discussed all that widely on the outside. That's what I want to talk about.
让Google的程序如此优秀的一个最重要的事情看起来是非常的简单：代码审查。并不是只有Google做这个事情—代码审查已经被广泛的认可为一种非常好的做法，很多人都在这样做。但我还没有看到第二家这样大的公司能把这种事情运用的如此普遍。在Google，没有程序，任何产品、任何项目的程序代码，可以在没有经过有效的代码审查前提交到代码库里的。
The biggest thing that makes Google's code so good is simple: code review. That's not specific to Google - it's widely recognized as a good idea, and a lot of people do it. But I've never seen another large company where it was such a universal. At Google, no code, for any product, for any project, gets checked in until it gets a positive review.
所有人都要经过代码审查。并且很正规的：这种事情应该成为任何重要的软件开发工作中一个基本制度。并不单指产品程序——所有东西。它不需要很多的工作，但它的效果是巨大的。
Everyone should do this. And I don't just mean informally: this should really be a universal rule of serious software development. Not just product code - everything. It's not that much work, and it makes a huge difference.
从代码审查里能得到什么？
What do you get out of code review?
很显然：在代码提交前，用第二群眼睛检查一遍，防止bug混入。这是对其最常见的理解，是对代码审查的好处的最广泛的认识。但是，依我的经验来看，这反倒是它最不重要的一点。人们确实在代码审查中找到了bug。可是，这些在代码审查中能发现的绝大部分bug，很显然，都是微不足道的bug，程序的作者花几分钟的时间就能发现它们。真正需要花时间去发现的bug不是在代码审查里能找到的。
There's the obvious: having a second set of eyes look over code before it gets checked in catches bugs. This is the most widely cited, widely recognized benefit of code review. But in my experience, it's the least valuable one. People do find bugs in code review. But the overwhelming majority of bugs that are caught in code review are, frankly, trivial bugs which would have taken the author a couple of minutes to find. The bugs that actually take time to find don't get caught in review.
代码审查的最大的功用是纯社会性的。如果你在编程，而且知道将会有同事检查你的代码，你编程态度就完全不一样了。你写出的代码将更加整洁，有更好的注释，更好的程序结构——因为你知道，那个你很在意的人将会查看你的程序。没有代码审查，你知道人们最终还是会看你的程序。但这种事情不是立即发生的事，它不会给你带来同等的紧迫感，它不会给你相同的个人评判的那种感受。
The biggest advantage of code review is purely social. If you're programming and you know that your coworkers are going to look at your code, you program differently. You'll write code that's neater, better documented, and better organized -- because you'll know that people who's opinions you care about will be looking at your code. Without review, you know that people will look at code eventually. But because it's not immediate, it doesn't have the same sense of urgency, and it doesn't have the same feeling of personal judgement.
还有一个非常重要的好处。代码审查能传播知识。在很多的开发团队里，经常每一个人负责一个核心模块，每个人都只关注他自己的那个模块。除非是同事的模块影响了自己的程序，他们从不相互交流。这种情况的后果是，每个模块只有一个人熟悉里面的代码。如果这个人休假或——但愿不是——辞职了，其他人则束手无策。通过代码审查，至少会有两个人熟悉这些程序——作者，以及审查者。审查者并不能像程序的作者一样对程序十分了解——但他会熟悉程序的设计和架构，这是极其重要的。
There's one more big benefit. Code reviews spread knowledge. In a lot of development groups, each person has a core component that they're responsible for, and each person is very focused on their own component. As long as their coworkers components don't break their code, they don't look at it. The effect of this is that for each component, only one person has any familiarity with the code. If that person takes time off or - god forbid - leaves the company, no one knows anything about it. With code review, you have at least two people who are familiar with code - the author, and the reviewer. The reviewer doesn't know as much about the code as the author - but they're familiar with the design and the structure of it, which is incredibly valuable.
