Recent content in Julio Merino's corner on Julio Merino (jmmv.dev)
Extending getopts into a small framework for Unix-style Rust command-line tools. Over the years, I’ve written tens of command-line applications in many different languages—shell is probably the top contender, believe it or not—and for various ecosystems. Along the way, I’ve developed… let’s say… opinions on how they should behave . But behavior and…
How to leverage an old dirty trick in your Bazel wrapper for great effect As powerful as Bazel is, sometimes it’s not featureful enough. When using this build system, it’s common practice to wrap it in a launcher script—and in fact, this is natively supported by Bazelisk , Bazel’s native dispatcher that stands for the bazel binary in the user’s PATH . Bazelisk will…
In a recent discussion at the orange site sparked by the Emacs 31 Is Around the Corner: The Changes I’m Already Daily Driving article, people were asking themselves “Is anyone still using Emacs?” and then providing their own perspective. For me, the answer is a resounding yes… but the interesting part is that I’m not still using Emacs: I’m actually using Emacs…
This article is not about AI and it is not written with AI, but the work that I’m about to present was definitely motivated by AI. And because I generally like telling stories, I have to give you that background. Do with that whatever you want, but… it’d be a pity if you left just because the AI word showed up in the first paragraph! I think the technical explanation that…
Six years have passed since I started building EndBASIC : a retro-looking BASIC interpreter that works on the web, on the desktop, and on embedded hardware—and that allows writing cross-platform apps that leverage graphics, a cloud file sharing system, and even access to local hardware via GPIO. But as cool as this sounds, and as exciting as the journey has been, there is something that…
Why agentic coding changes everything for the open-source craft and maintainership. It has been two months since I’ve been using AI coding agents “for real”. In my previous article , I reflected on my experiment to vibe-code a full Emacs module from scratch. In there, I intentionally left one important question unanswered: what is the meaning and impact of agentic coding on the…
It has now been a month since I started playing with Claude Code “for real” and by now I’ve mostly switched to Codex CLI: it is much snappier—who would imagine that a “Rewrite in Rust” would make things tangibly faster—and the answers feel more to-the-point than Claude’s to me. As part of this experiment, I decided to go all-in with the crazy idea of…
Or the more tired “One week with Claude Code”-type article. It’s no secret that I’ve been grumpy about the new AI-based coding trend. I’ve been grumpy about the “push from above to use AI or else”. I’ve been grumpy about the eye-rolling hype I see on LinkedIn. I’ve been grumpy about being on the receiving end of vibe-coded PRs that…
A little over two years ago, I wrote an article titled SSH agent forwarding and tmux done right . In it, I described how SSH agent forwarding works—a feature that lets a remote machine use the credentials stored in your local ssh-agent instance—and how using a console multiplexer like tmux or screen often breaks it. In that article, I presented the ssh-agent-switcher : a program I put…
Putting FreeBSD’s “power to serve” motto to the test. On Thanksgiving morning, I woke up to one of my web services being unavailable. All HTTP requests failed with a “503 Service unavailable” error. I logged into the console, saw a simplistic “Runtime version: Error” message, and was not able to diagnose the problem. I did not spend a lot of time trying to…
It has been just over two years since I started Blog System/5, and that means it’s time for the now-usual(?) BazelCon 2025 trip report! The conference, arranged by the Linux Foundation, took place in Atlanta, GA, USA over three days: one for tutorials and two for the main talks. An extra hackathon day, organized by Aspect Build, followed. Unfortunately, a canceled flight meant I missed the…
I’ve heard it from people new to Bazel but also from people very familiar with the Bazel ecosystem: BUILD files must go away. And they must go away because they are redundant: they just repeat the dependency information that’s already encoded in the in-code import/use statements. Hearing this from newcomers to Bazel isn’t surprising: after all, most newcomers are used to build…
Imagine this scenario: your team uses Bazel for fast, distributed C++ builds. A developer builds a change on their workstation, all tests pass, and the change is merged. The CI system picks it up, gets a cache hit from the developer’s build, and produces a release artifact. Everything looks green. But when you deploy to production, the service crashes with a mysterious error: version…
The previous article on Bazel remote caching concluded that using just a remote cache for Bazel builds was suboptimal due to limitations in what can and cannot be cached for security reasons. The reason behind the restrictions was that it is impossible to safely reuse a cache across users. Or is it? In this article, we’ll see how leveraging remote execution in conjunction with a remote cache…
The previous article on Bazel action non-determinism provided an introduction to actions: what they are, how they are defined, and how they act as the fundamental unit of execution in Bazel. What the article did not mention is that actions are also the fundamental unit of caching during execution to avoid doing already-done work. In this second part of the series, I want to revisit the very basics…