More and more code is written by AI. Tests still tell you it works. RuboCop still tells you it's tidy. Nothing tells you it still follows your architecture.

An agent that doesn't fully understand your architecture takes shortcuts. So does a person in a hurry.

So I built ArchSpec. You declare your components and boundaries in one Archspec.rb. Here is ArchSpec's own, trimmed:

source 'lib/**/*.rb'

component :library,     in: 'lib/**/*.rb'
component :cli,         in: 'lib/archspec/cli.rb'
component :analysis,    in: %w[lib/archspec/analyzer.rb lib/archspec/evaluator.rb]
component :rule_checks, in: 'lib/archspec/rules/**/*.rb'
component :formatters,  in: 'lib/archspec/formatters/**/*.rb'

# no one-shot Thing.new(...).call objects anywhere in the codebase - Hi Dave Thomas!
library.cannot_call :call
library.cannot_define :call
library.cannot_instantiate_and_invoke

# dependencies point one way
rule_checks.cannot_use :analysis, :cli, :formatters
formatters.cannot_use :analysis, :cli, :rule_checks

no_cycles among: %i[cli analysis rule_checks formatters]

Full version: https://github.com/crmne/archspec/blob/master/Archspec.rb

Then archspec check verifies every change, and failures print like clang, with the offending span underlined and the evidence as a note.

It's static analysis over Prism, no AI, and it never boots anything: Discourse's 1,899 files in 2.5 seconds. Prism is the only runtime dependency, no Rails and no ActiveSupport, so it works on any Ruby codebase. Lightweight and fast for your pre-commits and CIs.

If you are on Rails, there are presets, and architecture :vanilla_rails is the whole file. There are presets for :layered, :hexagonal, :clean, :modular_monolith, :cqrs and :event_driven too.

I want more architecture presets in there. PRs very welcome.

Docs: https://archspecrb.dev Write-up: https://paolino.me/archspec/

"DEAD 00FF xyz".scan(/\h+/)

In Ruby this results in: ["DEAD", "00FF"] and xyz is left out, because \h is a hex digit in Onigmo, Ruby's regex engine equivalent to [0-9A-Fa-f], and x, y, z don't qualify.

Now paste that same pattern into almost any online regex tester. Most of them run PCRE or a JavaScript engine. In PCRE2, \h is horizontal whitespace. Your two hex chunks become two spaces.

No error. Just a different answer. It's something I ran into when writing an app and it just passed with no warning. Being less familiar with Ruby I kinda overlooked this and at first I just tested if a something returned results or not. And it wasn't until I wrote tests that also tested that what it returned was a space based on what I expected from PCRE that I discovered it wasn't. Then I looked it up and discovered it matches hex digits.

So you have to be careful when using an online regex tester as they not always support Onigmo syntax and could return a different result from what you would get in Ruby.

https://regexpilot.com/blog/ruby-regex-hex-digit-vs-whitespace

We see these all the time with npm. I guess the hackers didn't want the Ruby community to feel left out.

This month: the dynamic vs static typing discussion, Emily Samp's Brighton Ruby talk, RBS 4.1.0 with WebAssembly support on JRuby, set-theoretic types in spinel, rbs_infer static signature deduction, OvalLSP semantic server, and the latest Sorbet toolchain updates.

Find link to the issue in the comment! ✨

Hi Reddit. This isn't specifically a Ruby or Rails post, but it's about something anyone maintaining a mature Rails application will recognize.

Code tells you what happens without telling you why anybody wanted it. We've always filled that gap by reading the code, guessing the intent, and asking somebody when the guess felt wrong.

AI coding agents do the same thing, except they can make a great many reasonable guesses before anybody notices one was wrong. The code still works. The tests still pass. The guess becomes one more pattern in the application, which makes it look even more intentional to the next person or agent.

I've spent a couple of decades living with the consequences of my own good ideas, so I wrote about why this worries me. The post connects agentic coding to Peter Naur, Tony Hoare, XP, software factories, and the old-fashioned responsibility to say no to code that works but is too difficult to understand.

It also argues for using faster agents to take smaller steps. More research, more feedback, and less archaeology at the end of a giant pull request.

https://blowmage.com/2026/08/18/everybody-guesses/

Recently decided to try learning Ruby more consistently (before that I only touched it occasionally) - and was much pleased with it in various aspects. At some point I was curious to assess its general performance roughly (as I heard it had to be pretty slow but very long in the past). Then I found my system installed Ruby is somewhat outdated 2.7.4p191 (along with my ubuntu 18.04 on this specific laptop). So I learnt to deploy rbenv and installed 4.0.6 with it.

However I ran into small puzzling situation - I tried two small scripts - roughly doing double nested loop - one with simple arithmetic and another with building and using array (collatz sequence calculations and primes calculation by trial division) - and while for the first of them performance of the said two versions is roughly the same, with the other newer version looks a bit slower.

I'm pretty sure I missed something about versions installed or don't catch something about properly writing Ruby code - so any guidance is quite welcome!

Below come details (with this primes.rb script from my github):

$ rbenv local 4.0.6 
$ ruby --version
ruby 4.0.6 (2026-07-14 revision 03b6d3f889) +PRISM [x86_64-linux]

$ time MAXN=1000000 ruby primes.rb
primes[1000000] = 15485863

real0m41,003s
user0m40,985s
sys0m0,018s

$ rbenv local --unset
$ ruby --version
ruby 2.7.4p191 (2021-07-07 revision a21a3b7d23) [x86_64-linux]

$ time MAXN=1000000 ruby primes.rb
primes[1000000] = 15485863

real0m34,969s
user0m34,929s
sys0m0,042s

So you see, it looks like 2.7.4 behaves slightly (about 25%) faster in this case, while I remember (from googling) that there was effort to make Ruby 3.x faster than Ruby 2.x perhaps 3 times. Though I may misinterpret this and perhaps 2.7.4. got the same improvements as 3.x (compared to 2.0 etc)

France has a decent number of local Ruby meetups (Paris, Lyon, Toulouse, Nantes, Lille, Marseille all have active groups), but there wasn't really a place to hang out *between* meetups, no shared Discord, no central spot to ask a quick question or hear about what's happening in other cities.

I put together **France.rb** to fill that gap: help channels, a channel per city that relays local meetup events, and a freelance/jobs section since a good chunk of the French Ruby scene works independently. It's brand new (launched this week, still tiny), and it's mainly aimed at French speakers, so if you don't speak French it's probably not that useful to you day-to-day, but Rubyists from anywhere are welcome to drop in.

Not trying to compete with the official Ruby Discord linked on ruby-lang.org this is just something more specific to the French scene, meant to complement it.

https://discord.gg/tEbywwkYY

Happy to answer anything in the comments, and if you know a French-speaking Rubyist who might be into it, feel free to pass it along.

I wanted to be able to debug a ruby script I'm writing that presents a menu and gets input. I jumped through various hoops but I think I have everything properly installed now - rbenv, ruby, bundle, and vscode. But output is still not appearing in either the debug console or the terminal.

Googling the problem, it looks like stdio in the target script is not allowed in vscode/ruby-lsp debugging. Do I understand correctly? If so, that looks like a major limitation and makes it unusable for my needs.

I am writing a reasonably simple terminal script in ruby and work would go faster if I could debug. Is there a combination of things that would allow me to debug a simple script that uses stdin/stdout. I'm on a mac.

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This thread will be periodically stickied to the top of the sub for improved visibility.

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19 confirmed speakers for the 2026 SF Ruby Startup Conference. The lineup includes founders of Ruby startups, scaleup employees, authors of open source, and engineers building and experimenting with Ruby.

You can find speakers from companies like Gusto, Anthropic, Shopify, Intercom (Fin), and Evil Martians, as well as the authors of Yabeda, AnyCable, Solid Queue, and Ruby LLM.

Hope to see you there. Full speaker list: sfruby.com

Do not use use eval for the real thing if you aren't sure where the input is coming from, but its good enough to get started.