James Munns
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James Munns
@jamesmunns.com
6.7K followers 840 following 8.1K posts
Notable Protocol Enjoyer.

Doing stuff, mostly in Rust and on Embedded systems.
Co-host @sdr-podcast.com

DMs (matrix): @jamesmunns:beeper.com
DMs (signal): jamesmunns.255

he/him
Kein Ort für Nazis
Posts Replies Media Videos
Reposted by James Munns
ferroussystems.bsky.social
Universal Signalling and the Ferrocene team are developing the first railway certification package for Rust under EN 50716, establishing a pathway for Rust in safety-critical railway applications.

Read more: bit.ly/4z193o6

#UniversalSignalling #Ferrocene #RustLang #RailTech
Social media graphic on a light gray grid background with scattered pastel-colored squares. The blue Ferrous Systems logo appears in the upper left. A large rounded light-blue panel features a green “FERROCENE NEWS” banner and the headline “All aboard the Rust train!” with a train emoji. Below, text announces that Universal Signalling selects Ferrocene to develop the first Rust-based railway certification package in compliance with EN 50716.
September 29, 2026 at 12:07 PM
Reposted by James Munns
mattkeeter.com
hi friends

I'm very excited to announce Halfspace, my experimental cross-platform IDE for solid modeling with distance fields!

This has been in progress since midway through last year, and it's finally "done enough" to make it more public.
Halfspace
An IDE for solid modelling with distance fields
www.mattkeeter.com
September 28, 2026 at 5:56 PM
Reposted by James Munns
petelevasseur.com
proud to share that I was selected to serve on the Rust Project Leadership Council!

my role's to represent the interests of the top-level Language team, and all sub-teams =)
Screenshot showing Pete LeVasseur as the Language team representative to the Rust Project Leadership Council.
September 28, 2026 at 2:59 PM
Reposted by James Munns
nia.is.fckn.gay
I'm officially lead of the rust library team! i don't have anything corny to say about it I'm just viciously proud of myself
rust-lang.org/governance/t...
Library team
A language empowering everyone to build reliable and efficient software.
rust-lang.org
September 28, 2026 at 12:59 AM
Reposted by James Munns
sunshowers.io
Friends don't let friends use serde_json::Value as a stepping stone
Appendix: why not serde_json::Value? For reading versioned data, a naive implementation might do something like: struct ReadEnvelope { version: u32, data: serde_json::Value, } impl ReadEnvelope { fn deserialize_data<T: serde::de::DeserializeOwned>( &self, ) -> Result<T, serde_json::Error> { serde_json::from_value(self.data.clone()) } } But this has a few pitfalls: serde_json::Value has funky behavior around objects in a few different ways. For a payload like {"a":1,"a":2}, serde_json::Value drops the first a and only keeps the last one. This crate lets the deserialized type decide what to do with duplicate keys (a derived Deserialize would typically reject duplicate keys). There is no workaround for this with serde_json::Value. Object key order is only preserved if the preserve_order feature is enabled. This can lead to surprising roundtrip behavior. There are a couple different workarounds, neither of which is satisfying: Enable the preserve_order feature, which affects all other crates in the Cargo dependency graph. Accept that key order might not roundtrip. This feature-flag coupling is hard to explain to users; we can do much better than this. With default features, serde_json::Value cannot represent certain types that serde itself supports deserialization for, such as u128s. Like 1.2 above, turning on arbitrary_precision would fix this, but that is undesirable for the same reasons. If deserialization fails, the error message doesn’t carry a line/column offset. An in-between option is serde_json::value::RawValue, which allows part of a JSON payload to be stored as a string, and addresses points 1 and 2. But for point 3, RawValue produces incorrect line and column offsets on error (the offsets produced are relative to the captured part of the payload, not relative to the full payload). Incorrect values are worse than not having the line and column offsets at all. Instead of either option, we perform passes over the underlying JSON directly: The first pass validates that the JSON is well-formed, and for envelope reads, records which top-level fields are present. For envelope reads, the second pass reads the version, ignoring the data. Then, depending on the read method called, we perform one or more deserialization passes through the VersionSet::parse callback. Why not one streaming pass? Because data could come before version, for example if serde_json::Value is used without preserve_order, or with jq -S.
September 27, 2026 at 8:58 PM
jamesmunns.com
I've always assumed that the build tool "buck" was named after the parts used to shape a form in vacuum forming or leather working (literally, a tool for building something), but I actually can't find any mention of that, and I'm slightly amazed they backed into a good play on words by accident.
September 25, 2026 at 5:38 AM
Reposted by James Munns
indirect.io
OH Functional programming is when Rust people read your code and go "what the fuck (laudatory)". Imperative programming is when Rust people read your code and go "what the fuck (derogatory)"
September 24, 2026 at 5:34 PM
Reposted by James Munns
predr.ag
GitHub Actions + Rust's Miri can leak your secrets in CI 🧵

If you run Miri in CI:
- upgrade to the 2026-09-22 nightly
- clear caches
- rotate any secrets that the `cargo miri` CI job had access to

GPT-6 Astra helped find this 🦀
GitHub Actions makes it possible to cache directories between runs. Typical setups allow CI runs on main (and other branches) to write to cache, and PRs can only read from cache (preventing cache poisoning). Rust projects tend to speed up CI by caching binaries built by cargo install and sometimes the contents of target/. PR CI can be triggered by anyone who can open PRs on your repository. GitHub requires maintainer approval for the first PR, but future PRs will rerun CI on every push. Anyone who has previously landed a change can trigger a CI run extracting information from cached target/ and then cover their tracks by pushing a second commit to the PR. GitHub sometimes hides overwritten commits in its UI, making this kind of attack harder to detect. CI run logs and overwritten commits are also deleted after a few months. When cargo miri is invoked, Miri needs to retain build-relevant environment variables between runs. The current code to do so achieves this by storing all environment variables to target/. This, of course, persists when target/ is cached. If your environment contained secrets, these can now be accessed by PRs via the cache.
September 21, 2026 at 8:03 PM
jamesmunns.com
Flight currently delayed 2.5 hours, I'm not sure if I'd rather it leave asap, or delay another 1.5h for that sweet sweet 600 EUR payout.

So far they've gifted me a 7EUR voucher, which I might be able to get a beer with! We will see!
September 19, 2026 at 9:35 AM
jamesmunns.com
Come to Flughafen Frankfurt Terminal Z in the next 20 minutes if you need an ass-kicking
steveklabnik.com Steve Klabnik @steveklabnik.com · 10d
Come to Aéroport de Paris-Charles de Gaulle in the next 91 minutes if you need an ass-kicking
September 19, 2026 at 7:46 AM
Reposted by James Munns
rust-lang.org
⚠️ We believe that there is an ongoing campaign targeting owners of popular crates and rust-lang team members that is attempting to compromise devices and accounts in order to use them to publish malware.

See our blog post for details: blog.rust-lang.org/2026/09/17/t...
Be alert: targeted attacks on prominent Rustaceans | Rust Blog
Empowering everyone to build reliable and efficient software.
blog.rust-lang.org
September 17, 2026 at 7:45 PM
Reposted by James Munns
mara.bsky.social
You can now sponsor RustNL's Rust Maintainer Team through GitHub Sponsors: github.com/sponsors/rus...

The page also lists other options to send us money.

With your support, we can make sure the Rust project stays well maintained and grow our team with new talent. 💛
September 17, 2026 at 2:28 PM
jamesmunns.com
Even if you filtered notifs just to people who liked + reposted it (and maybe kept the original post but visually marked it in appviews + embeds?), that actually would be a *really* cool feature.
fasterthanli.me amos @fasterthanli.me · 12d
A retraction would be nice but the lie has been spreading for days. Plus until the day social media platforms get a "Retract" button that blasts everyone who's seen the original post... it won't work.
September 17, 2026 at 12:44 PM
Reposted by James Munns
myrrlyn.net
dang i heard drew got woke i didn’t realize he got WOKE
September 16, 2026 at 9:44 PM
Reposted by James Munns
myrrlyn.net
i lost a big swath of my #rustlang muties during The Great Sundering but if any of you people are interested i have a job description for ya in the bae area

looks interesting but i am committed to being Never Californian so

job-boards.greenhouse.io/intrinsicrob...
Full Stack Software Engineer - Factory Orchestration
Mountain View, California
job-boards.greenhouse.io
September 15, 2026 at 5:52 PM
jamesmunns.com
Oh woah
September 14, 2026 at 7:44 AM
jamesmunns.com
I want to write a simulation of this that uses the center of mass (the orange dot here) to pick a position on an HSV color wheel. Use the angle as the huge, use distance from the center as the saturation and/or brightness.

I need to add smartled/ws2812b support to hubris.
matthen.com Matt Henderson @matthen.com · 15d
Approximating the Lorenz attractor with a chaotic leaky water wheel.

The orange dot is the centre of mass of the water. It traces (a projection of) the familiar attractor as the wheel spins seemingly randomly left and right.
September 13, 2026 at 9:05 PM
Reposted by James Munns
kev507.bsky.social
Building the Oxide Data Center Explorer with Astra
Grid of seven screenshots from an interactive 3D tour of an illustrated Oxide data hall. Scenes move from a row of black Oxide racks with green sled faceplates and yellow overhead cabling, to close-ups of a compute sled pulled out from the rack, a front-loading storage sled, a network switch drawer, and power shelves with bundled cables. Each frame has a dark panel with a stop title and description, such as Cloud infrastructure in your data center and Storage spans the rack, plus tour controls for Back, Pause, and Next.
September 11, 2026 at 8:24 PM
jamesmunns.com
Great now I want Zapiekanka
kira.ws kira ☆ @kira.ws · 18d
polish invention of national importance: the czosndog. a hot dog whose bun is an entire garlic baguette. czosnek = garlic. split it, sausage in, cheese on top, bake. bacon, chilli and spring onion if you respect yourself. born on wykop in 2020, beloved since
a czosndog: garlic baguette as the bun, sausage inside, melted cheese, bacon bits, fresh chilli and spring onion on top, on a wooden board
September 11, 2026 at 7:03 PM
jamesmunns.com
For Indie Revival, I'm counting:

* Bloc Party
* Broken Social Scene
* Dandy Warhols
* Death Cab
* Interpol
* Metric
* Modest Mouse
* The Strokes
* Young The Giant

AND SKA too!

* Big D and the Kids Table
* Goldfinger
* Streetlight Manifesto

wtf, 2026? en.wikipedia.org/wiki/List_of...
September 11, 2026 at 8:59 AM
jamesmunns.com
I bought a tiny travel scale (for weighing myself), and:

1. It is silly small, like the size of a kitchen scale or an A5 sheet of paper, but it does work better than you think it would if you balance on it.
2. It does read ~0.6kg under my usual scale, and I have no way to calibrate either scale.
A very small scale with the brand "TANITA" and a big screen, sitting on top of an A4 notepad clipboard. It is roughly the size of an A5 sheet of paper (scale: 190mm x 135mm, A5: 210mm x 148mm).
September 11, 2026 at 7:59 AM
Reposted by James Munns
rustnl.bsky.social
** Ticket sales now open ** Get your tickets for RustWeek 2027!

We lowered the ticket prices: privately-paid tickets are now 199 instead of 249 euro. A checkbox enables a 100 euro discount for those who can't afford the full price ✨️.

See you in Utrecht!

2027.rustweek.org

#rustweek2027 #rust
RustWeek 2027 - RustWeek 2027
RustWeek 2027, The Netherlands - May 24–29 2027. The world's biggest Rust conference returns to beautiful Utrecht, welcoming over 900+ community members, professionals and the maintainers of Rust.
2027.rustweek.org
September 10, 2026 at 1:00 PM
Reposted by James Munns
bcantrill.bsky.social
Slides from my keynote this morning at #RustConf on the history of Rust at @oxide.computer; video to come!
speakerdeck.com/bcantrill/ru...
Rust, In Sickness & In Health
Keynote given at RustConf 2026 on September 10th, 2026 in Montreal. Video to come!
speakerdeck.com
September 10, 2026 at 1:54 PM
jamesmunns.com
36 weeks into the year: It's still going!

Recently bumped up my activity level by trying to consistently walk 30-60m a day, it seems to be helping the progress.

One graph of the last 6mo (with variance bars), one graph of the whole year (without).

Down a total of 17.9kg/39.4lbs, and 62.9% done.
A graph showing weight over time. It starts in March, at around 98.3kg, and ends mid-Sept at around 85.5kg. There is a red trendline that is largely moving downwards, with a somewhat wavy plateau between mid-May and early July. There are green "variance" bars showing the daily weight measurements being mostly below but sometimes above the trendline. A similar graph as before, but shows a red trendline that starts at 103.8kg on Jan 1st, and ends at 85.5kg today Sept 10th. Instead of green variance bars, there is a hard-to-see grey line showing the daily weights. It is much noisier than the red trendline.
September 10, 2026 at 8:16 AM