We've already explored some of the dark corners of Rust semantic versioning on this blog:

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This post describes work in progress: how cargo-semver-checks will benefit from the upcoming query optimization API in the Trustfall query engine. Read on to learn how a modern linter works under the hood, and how ideas from the world of databases can improve its performance.

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I recently embarked on a quest: revamp the cargo-semver-checks import-handling system so that moving and re-exporting an item stops being incorrectly flagged as a major breaking change. This is how crate authors can reorganize or rename items: just re-export the items in the original location under … read more

I've been saying for a while now that semantic versioning in Rust is tricky and full of unexpected edge cases. My last post mentioned that some Rust structs can be converted into enums without requiring a major version bump. It introduced a non-exhaustive struct called Chameleon that had no public f… read more

EDIT: The Rust API evolution RFC distinguishes between breaking changes and changes that require a new semver-major version (called major changes). All major changes are breaking, but not all breaking changes are major. Changing a struct to an enum is always breaking (as pointed out on r/rust) but i… read more

cargo-semver-checks ends 2022 with 40,000 downloads from crates.io, able to prevent 30 different kinds of semver issues, and having done so in real-world use cases. Inspired by Yoshua Wuyts' "Rust in 2023 (by Yosh)" post, here are my thoughts on cargo-semver-checks in 2022, and what I look… read more

Undefined behavior (UB) is a tricky concept in programming languages and compilers. Over the many years I've been an industry mentor for MIT's 6.172 Performance Engineering course, An excellent class that I highly recommend. It's very thorough and hands-on, at the expense of also requiring a lot of… read more

I had a lot of fun spending nights-and-weekends time participating in the HYTRADBOI Jam, a global hack week aimed at building "exciting and weird" data-centric solutions to familiar problems. The name HYTRADBOI might sound familiar: the jam is associated with the same conference where I gave my "How to Query (Almost) Everything" talk talk in April this year.

I jammed on two projects: one solo and one with a friend. The projects ultimately were very successful and mostly-successful, respectively. read more

The saying usually goes: "If at first you don't succeed, try, try again." But in the Safari web browser under the right conditions, trying again after succeeding once can get you in trouble. This is my recent debugging adventure. read more

I recently built cargo-semver-checks, a linter that ensures crates adhere to semantic versioning. This is why and how I built it.

Fearless development is a key theme throughout Rust. "If it compiles, it works", fearless concurrency, etc.

But there's one aspect of Rust (and nearly all other languages) that isn't entirely fearless yet: cargo update, upgrading the versions of the project's dependencies.

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A beginner-friendly introduction to compilers: follow along as we build a compiler from scratch, or fork the code on GitHub and add your own optimizations too! In this episode: value numbering helps track how values are used in the program. Last time on Compiler Adventures, we implemented constant p… read more

Happy April 1st! A group of folks and I decided to do something different this year: instead of publishing fake things, we’re publishing real posts on very different topics than our readers usually expect from our blogs. The tech content will be back soon! Check out the other April Cools posts here.… read more

A beginner-friendly introduction to compilers: follow along as we build a compiler from scratch, or fork the code on GitHub and add your own optimizations too! In this episode: propagating constant values to eliminate more instructions. Last time on Compiler Adventures, we wrote an optimization that… read more

A beginner-friendly introduction to compilers: follow along as we build a compiler from scratch, or fork the code on GitHub and add your own optimizations too! In this episode: eliminating no-op instructions. What part of computer science feels most like arcane magic? I'd say compilers. "The ma… read more

Distributed systems courses frequently introduce the Paxos and two-phase commit (2PC) protocols in quick succession. On one hand, this is a reasonable educational choice, as Paxos and 2PC are both examples of consensus algorithms used in the real world. On the other, it leads many students toward th… read more