# Google's Titus Winters on C++ refactoring, mandatory testing, and CS curriculum reform

> Original title: How did Google refactor 250M lines of C++ code, pre-AI, what happened when Search could no longer ship on the regular cadence due to regr...

- Source: Gergely Orosz
- Published: 2026-10-29T13:54:49.000Z
- Bad Influence: https://badinfluence.news/items/e5zosjqzbpokhyeijthykbu26
- Original: https://x.com/GergelyOrosz/status/2115804551672725928

## Summary

Titus Winters discusses how Google refactored about 250M lines of C++ code and what happened when Search could no longer ship on its regular cadence. He says the CS undergraduate curriculum, which he believes has changed little since around 2000, needs major revision to cover testing and verification.

## Post

How did Google refactor 250M lines of C++ code, pre-AI, what happened when Search could no longer ship on the regular cadence due to regressions, and why is it time to completely redo the CS curriculum? With @TitusWinters. Timestamps:

00:00 Intro
07:01 Getting hired by Google
09:48 Finding his niche at Google
14:32 Why Google made testing mandatory
17:45 Why new engineers fear making mistakes
20:40 Abseil: C++ foundations at Google
23:09 Google’s massive C++ refactoring
30:48 AI for rewrites
39:07 Software Engineering at Google: the book
43:10 Google’s readability reviews
47:18 Why teams still matter
52:41 Psychological safety
58:17 Layoffs and culture
1:02:11 Measuring developer productivity
1:11:17 Rethinking CS education
1:22:56 What new grads should learn
1:32:08 Titus’s ideal software engineering curriculum
1:36:27 Advice for breaking into tech
1:38:35 Book recommendation

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Three interesting details:

1. Google made automated tests mandatory after Search could no longer ship regularly.

Around 2007, Search, the flagship product, was unable to ship at a monthly cadence any more, and the best they could ship to production was quarterly.
Almost every change at Google touched Search’s code, even things like a change to Gmail. To clamp down, Google, as an org, mandated that every change was to be accompanied by a test. Over time, Search returned to its former higher cadence.

2. Google’s readability program might have been the largest educational program ever in tech.

To make a code change at Google, two people need to sign off that change through a code review:

a) An “owner” of the file/project: someone on the team with domain knowledge

b) A “readability” reviewer: an engineer certified to be a “readability” expert in the given language that the change was made in

Google’s first engineer, Craig Silverstein, walked each new dev hire through their first change. Java teams turned this approach into mentoring, where experienced reviewers were assigned to review all changes in a round-robin fashion. And soon enough, a formalized readability program was built for all languages. When Titus left Google three months ago, 10,000+ engineers were enrolled in readability at any given time. Has there ever been a bigger engineering “classroom” anywhere else?

3. Burn down the US undergrad CS curriculum (most of it)

Titus was the only working engineer on the steering committee for the ACM/IEEE/AAAI CS curriculum guidelines in 2023, and believes the curriculum is hopelessly out of date. He accuses it of not having altered substantially since around 2000, while the industry has. Testing and verification are cited as mattering a lot more for new joiners, but they are absent from the curriculum.
Unless major changes are made to make it relevant, computer science enrollment could fall and software engineering programs that focus on practical dev skills will be attractive to students – this is Titus’s forecast.

[Video](https://badinfluence.news/api/img-proxy?u=https%3A%2F%2Fpbs.twimg.com%2Famplify_video_thumb%2F2115799620605587456%2Fimg%2F8jzwGX94wVleGkU7.jpg&mode=thumb&exp=1793491200&sig=7d6d29772e57bf5e)