--- title: "RubyGems' maintainer proposes cooldown feature" publication: "Ruby Weekly" issue: 792 published_at: "2026-03-19" canonical_url: "https://rubyweekly.com/issues/792" --- Plus the return of jemalloc, YJIT's tricky bug, RBS 4.0, and 37signals open sources Writebook. #​792 — March 19, 2026 [Read on the Web](https://rubyweekly.com/issues/792) Together with [![Sinaptia\](https://res.cloudinary.com/cpress/image/upload/c_fill,g_auto,e_trim,w_1280,h_229/e_make_transparent/co_white,e_outline:12/knobjaan0gn6j6hdyqzj.png)](https://sinaptia.dev/posts/no-ai-code-in-production-directive?utm_source=cooperpress&utm_medium=newsletter&utm_campaign=rubyweekly-2026q1&utm_content=primary) Ruby Weekly [![\](https://res.cloudinary.com/cpress/image/upload/w_1280,e_sharpen:60,q_auto/nzrmcyh6ioh7oxtgfrlj.jpg)](https://dev.to/hsbt/should-rubygemsbundler-have-a-cooldown-feature-40cp) [Should RubyGems/Bundler Have a 'Cooldown' Feature?](https://dev.to/hsbt/should-rubygemsbundler-have-a-cooldown-feature-40cp) — RubyGems’ maintainer reflects on the idea, quickly gathering steam with other package managers ([e.g.](https://pnpm.io/blog/2025/12/05/newsroom-npm-supply-chain-security#control-2-release-cooldown)), of having a waiting period before newly released packages are installed. Hiroshi says _yes_, but as an opt-in feature, as it's no silver bullet. Hiroshi Shibata [![\](https://res.cloudinary.com/cpress/image/upload/c_limit,w_480,h_480,q_auto/copm/b8d3c23b.png)](https://sinaptia.dev/posts/no-ai-code-in-production-directive?utm_source=cooperpress&utm_medium=newsletter&utm_campaign=rubyweekly-2026q1&utm_content=primary) [No AI Code in Production Directive](https://sinaptia.dev/posts/no-ai-code-in-production-directive?utm_source=cooperpress&utm_medium=newsletter&utm_campaign=rubyweekly-2026q1&utm_content=primary) — Have you heard Amazon now requires senior engineer approval for all AI-generated code after several severity-0 incidents? Should you ban it, too? We say: there's no such thing as AI code. There's just code. SINAPTIA sponsor [Ruby 4.0.2 Released to Fix a Tricky YJIT Bug](https://www.ruby-lang.org/en/news/2026/03/16/ruby-4-0-2-released/) — A routine update with a fix for [a YJIT bug](https://bugs.ruby-lang.org/issues/21941) that crashed processes. It was [noticed when running Puma in cluster mode](https://github.com/puma/puma/issues/3620) but affects any app where YJIT is enabled lazily and where local variables had escaped to the heap before YJIT started observing (there’s [a proof of concept](https://github.com/ruby/ruby/pull/16306/changes/feba10a15534b9faec63c74849987010ba74be66) in YJIT’s test suite). There's also a fix for [a GC-related perf regression.](https://bugs.ruby-lang.org/issues/21838) Takashi Kokubun **⚡️ IN BRIEF:** - `jemalloc`, the malloc implementation, has long provided [an interesting performance remedy](https://bugs.ruby-lang.org/issues/14718) in the Ruby world but [it became unmaintained](https://jasone.github.io/2025/06/12/jemalloc-postmortem/) last year. Well.. [Meta's investing in jemalloc and bringing it back.](https://engineering.fb.com/2026/03/02/data-infrastructure/investing-in-infrastructure-metas-renewed-commitment-to-jemalloc/) - [RBS 4.0](https://github.com/ruby/rbs/releases/tag/v4.0.0), Ruby's type signature language, has been released with _experimental_ inline syntax support so you can write type annotations directly in Ruby code, a la[RBS::Inline](https://github.com/soutaro/rbs-inline). - Should Ruby [get its own built-in CPU time profiler?](https://bugs.ruby-lang.org/issues/21950) - 🇮🇹 [Rubycon Italy](https://rubycon.it/), taking place this May 8, has just unveiled [its schedule](https://rubycon.it/schedule/), written in Ruby itself! [How ZJIT Removes Redundant Object Loads and Stores](https://railsatscale.com/2026-03-18-how-zjit-removes-redundant-object-loads-and-stores/) — [ZJIT](https://railsatscale.com/2025-12-24-launch-zjit/), optionally available in Ruby 4.0, is a new, alternative JIT compiler with the potential for being faster and easier to work on than YJIT over time. This article shows off some of how that potential is now bearing performance-shaped fruit. Jacob Denbeaux [How Much Time Could Your Team Save with 10x Faster CI?](https://go.fastruby.io/b9z) — We took a Rails 2.3 app to 8.1 and [cut CI from 40 to 4 minutes](https://go.fastruby.io/mp7). Ready for steady upgrades and faster CI? Contact us 🚀 Bonsai by FastRuby.io® sponsor 📄 [I Quit Rails Core 4 Years Ago: Here’s What I’ve Been Up To](https://kaspth.com/posts/i-quit-rails-core-4-years-ago-heres-what-ive-been-up-to) – What happens to core members when they leave the core? Kasper Timm Hansen 📄 [How to Declare Acronyms in Rails Inflections](https://andycroll.com/ruby/declare-acronyms-in-rails-inflections/) – For when you don’t want `"api".camelize` to be `"Api"` but `"API"`. Andy Croll 🤖 [Claude Code for Semi-Reluctant Rails Developers](https://robbyonrails.com/claude-code-curious-rails-developers/) – Helpful advice from a long-time Rails developer. Robby Russell 🛠 Code & Tools [![\](https://res.cloudinary.com/cpress/image/upload/w_1280,e_sharpen:60,q_auto/zz2ofe1xywfmfiidfbpu.jpg)](https://herb-tools.dev/blog/whats-new-in-herb-v0-9) [Herb v0.9: The Modern HTML + ERB Toolchain](https://herb-tools.dev/blog/whats-new-in-herb-v0-9) — Herb is an HTML+ERB toolchain (linter, rendering engine, LSP, formatter) supporting numerous languages (not just Ruby). v0.9 is a **huge** release with Action View tag helper support, a new `Herb.parse_ruby` API, a new default ‘strict’ parsing option, better error messages, and more. [Herb's site](https://herb-tools.dev/) has a new [Prism playground](https://herb-tools.dev/playground/prism#Q) which supports both Ruby and HTML+ERB. It's a great time to see what the Herb ecosystem offers. Marco Roth [HTTP.rb / HTTP 'The Gem!' 6.0: The Flexible HTTP Client](https://github.com/httprb/http/releases/tag/v6.0.0) — I love the `http` gem and its flexible, easy-to-remember API. v6 is the first major release in years, and adds RFC 7234-compliant [HTTP caching](https://github.com/httprb/http/pull/835), [instrumentation hooks](https://github.com/httprb/http/pull/832), [thread-safe request building](https://github.com/httprb/http/pull/829), a [`base_uri` option](https://github.com/httprb/http/pull/833), and more. http.rb team [AppSignal Monitors Your GVL (Yes, Really)](https://www.appsignal.com/?utm_source=newsletter&utm_medium=paid&utm_campaign=rubyweekly&utm_term=3-19&utm_content=sponsored-link) — With 21 Ruby libraries instrumented out of the box, including Solid Queue, Puma, and ViewComponent. Written in Rust, so it stays out of your app's way. Free for 30 days. No credit card. AppSignal sponsor [Ruby Native: The Tool I Wish I Had 25 Apps Ago](https://newsletter.masilotti.com/p/the-tool-i-wish-i-had-25-apps-ago) — [Ruby Native](https://rubynative.com/) is a commercial tool for turning Rails sites into iOS apps (think [Hotwire Native](https://native.hotwired.dev/) but without having to touch Swift). It’s currently in _preview_ but you can [try it out](https://rubynative.com/try). Joe Masilotti 💡 If you're interested in Rails, iOS, and Hotwire Native, [Joe's newsletter](https://newsletter.masilotti.com/) has a lot of high-value content, though only a limited amount can be read for free. 📕 [37signals Open Sources Its _Writebook_ Rails App](https://once.com/writebook) — Launched in 2024 in ‘source available’ form, 37signals has now opened up its Markdown Web book creator / renderer with the MIT license. [GitHub repo.](https://github.com/basecamp/writebook) 37signals / ONCE - 📈 [TestProf 1.6](https://github.com/test-prof/test-prof/releases/tag/v1.6.0) – Collection of tools to analyze and optimize Ruby test suite performance. Adds a TPS (tests-per-second) profiler and a GC profiling mode. - ⚛️ [React on Rails v16.4.0](https://github.com/shakacode/react_on_rails/releases/tag/v16.4.0) – Integrates React and Webpack with Rails, including server-side rendering of React. - 🔎 [rbspy v0.44.0](https://github.com/rbspy/rbspy/releases/tag/v0.44.0) – Sampling profiler for Ruby processes. Adds Ruby 4.0.2 support, a macOS binary for Apple silicon, and a `--duration` parameter to record for a specified number of seconds. - [SmarterCSV v1.16](https://github.com/tilo/smarter_csv/blob/main/CHANGELOG.md#1161-2026-03-16--bug-fixes--new-features) – Performance-focused CSV reading/writing library. The recent CHANGELOG entries are _very_thorough. - 🧊 [Refrigerator 1.9](https://github.com/jeremyevans/ruby-refrigerator) – Freezes Ruby core classes/modules to prevent runtime modifications. Now supports Ruby 4.0. - 🌐 [RouteTranslator 16.0](https://github.com/enriclluelles/route_translator) – Manage the translations of your Rails app's routes. - [Rails::Diff 0.7](https://github.com/MatheusRich/rails-diff) – Compare Rails-generated files with those in your repo. - [Brut 0.20](https://brutrb.com/) – Raw, standards-based, HTML-first web framework. - [Devise 5.0.3](https://github.com/heartcombo/devise/blob/v5.0.3/CHANGELOG.md#503---2026-03-16) lands an important security fix. - [ruby-duckdb 1.5](https://github.com/suketa/ruby-duckdb) – Ruby client for [DuckDB](https://duckdb.org/). 📰 Classifieds 💥 Are your job queues resilient? Our [Ultimate Guide To Scaling Sidekiq and Solid Queue](https://judoscale.com/blog/ultimate-guide-scaling-sidekiq?utm_source=ruby-weekly&utm_medium=newsletter&utm_campaign=content&utm_content=job-queues-resilient-ultimate-guide) shows you the way. --- 🔬 "Absolutely essential for AI agent-written PRs." [Undercover CI](https://undercover-ci.com) shows untested methods, right in your pull requests. --- [Help us save the German healthcare system](https://reimbursement.info/softwareentwickler-in%20) - Develop the leading healthcare stats platform with a small dedicated team in a stress free environment (Cologne based). --- 💎 [Hiring Senior Ruby on Rails Engineers at EverAI](https://jobs.ashbyhq.com/everai/3b22edca-5a41-4c00-9936-fda979904d81?utm_source=rubyweeklynewsletter): 50 million users, fully remote. Not used Ruby lately? That's okay, you can still apply! 📢 Elsewhere in the ecosystem [![\](https://res.cloudinary.com/cpress/image/upload/w_1280,e_sharpen:60,q_auto/vleephvykt5ci7kalfvc.jpg)](https://github.com/indutny/no-slop-in-nodejs-core) - 🤖 The Node.js community is wrestling with the role that LLM-produced code should play in its implementation, with the former creator of the _io.js_ fork [starting a petition to say 'no' to contributions built with AI assistance.](https://github.com/indutny/no-slop-in-nodejs-core) - Remember back in December when _WIRED_ published the widely-panned [Ruby Is Not a Serious Programming Language](https://www.wired.com/story/ruby-is-not-a-serious-programming-language/)? They're back at it, this time [calling COBOL the 'Asbestos of Programming Languages'](https://www.wired.com/story/cobol-is-the-asbestos-of-programming-languages/). - **;?** Some analysis of how different programming languages (including Ruby) [handle a lack of mandatory semicolons.](https://terts.dev/blog/no-semicolons-needed/) - One from the Postgres world: [how a single query blew up and consumed 2 terabytes of memory](https://mydbanotebook.org/posts/work_mem-its-a-trap/) before being taken down by Linux's OOM killer. - 🎂 Amazon's Sébastien Stormacq reflects on the ubiquitous [AWS S3 cloud storage system turning 20 years old.](https://aws.amazon.com/blogs/aws/twenty-years-of-amazon-s3-and-building-whats-next/) Curated by [Peter Cooper](https://twitter.com/cooperx86) and [Glenn Goodrich](https://twitter.com/ruprict). Published by [Cooperpress](https://cooperpress.com/). [Change your email](https://rubyweekly.com/edit_subscription/*|UID|*) or [Stop getting this newsletter.](https://rubyweekly.com/leave/*|UID|*) © Cooper Press Ltd · Fairfield Enterprise Centre, Louth, LN11 0LS, United Kingdom Other weekly newsletters we publish include [Postgres Weekly](https://postgresweekly.com/), [React Status](https://react.statuscode.com/), [Frontend Focus](https://frontendfoc.us/), and [JavaScript Weekly](https://javascriptweekly.com/).