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  • Jul 5, 2026

    Clojurists Together Update: May and June 2026

    Some of you might know that Clojurists Together are supporting my work on nREPL, CIDER and friends this year. Normally I send them a bi-monthly progress report, but I saw some other people who got funding for their OSS work publish those reports as blog posts for the broader public and I thought to try this for a change.

    The past two months were super productive. I had a lot of inspiration during this period and I managed to tackle a lot of long-standing ideas and issues across the entire nREPL/CIDER ecosystem. Funnily enough, I also managed to grow the ecosystem with a couple of brand new projects, but more about those later.

    The big highlights from my perspective:

    • CIDER 1.22 is out
    • CIDER 2.0 is essentially ready and needs more user testing
    • Sayid is reborn
    • Two brand new projects saw the light of day: port and neat
    • Piggieback 0.7.0 is out (and Weasel got modernized while I was in the area)
    • clj-refactor and refactor-nrepl got some love as well

    Below you’ll find more details about the work I did, project by project.

    CIDER

    CIDER 1.22 (“São Miguel”) landed in mid-June, wrapping up the 1.x series. Its main features:

    • a registry for jack-in tools, so third parties can plug new build tools and Clojure dialects into cider-jack-in
    • a “default session” escape hatch from sesman’s project-based dispatch
    • keyword-argument versions of the low-level request APIs, alongside a proper decoupling of the nREPL client layer from CIDER’s UI

    It also fixed a long list of small annoyances: severe editor lag in unlinked buffers, several TRAMP and SSH tunnel problems, request id leaks, and a bunch of broken menu entries.

    Right after that I switched the development version to 2.0 and most of the planned work is already done. The headline items so far:

    That last one deserves a special mention: evaluation results that are images now render inline out of the box, and file/URL results offer their content on demand, six years after the feature had to be disabled over its safety problems. There was also a big cleanup pass: consolidated configuration options, the REPL history browser renamed to cider-history to end a long-standing naming clash, theme-aware faces instead of hardcoded colors, refreshed docs and a regenerated refcard. CIDER 2.0 is available from MELPA snapshots and I’d love for more people to take it for a spin before the final release.

    cider-nrepl

    Lots of cider-nrepl releases, driving the CIDER work above:

    • cider-nrepl 0.60.0 added the ops backing the new protocol exploration commands (cider/who-implements, cider/type-protocols, cider/protocols-with-method).
    • cider-nrepl 0.61.0 brought ClojureScript test support, a ClojureScript macroexpansion fix, formatting that honors the project’s cljfmt configuration, and a pprint backed by orchard.pp.
    • cider-nrepl 0.62.0-alpha1 and 0.62.0-alpha2 hardened the content-type and slurp middleware (URL scheme allowlist, size caps, graceful fetch errors) and cleaned up the response protocol, which is what made it safe to turn rich content on by default in CIDER 2.0.

    Along the way the project’s build was migrated from Leiningen to tools.deps, which required a new MrAnderson release (see the blog posts below).

    Orchard

    Orchard, the library that powers much of cider-nrepl’s functionality, kept pace:

    • Orchard 0.42.0 and Orchard 0.43.0 continued the inspector polish, added symbol classification to orchard.meta, a programmatic listener API for the tracer, and protocol/multimethod introspection in orchard.xref. The project also moved to tools.deps and its CI now covers JDK 26.

    Sayid

    Sayid, the omniscient Clojure debugger, had been dormant for years and I finally gave it the revival it deserved:

    • Sayid 0.2.0 was the big modernization pass: new mx.cider/sayid coordinates, a documented nREPL middleware API, a consolidated op surface (37 ops down to 26) and fixes for the most annoying Emacs client breakages.
    • Sayid 0.3.0 followed with usability work: no more frozen Emacs during the reload workflow, simpler query commands and help buffers generated from the keymaps.

    port

    port is a brand new project I started in May: a minimalist Clojure interactive programming environment for Emacs, built on prepl instead of nREPL. It went from nothing to three releases in the course of the month:

    • port 0.1.0
    • port 0.2.0
    • port 0.3.0, which added eldoc with active argument highlighting, a wire-level message log for debugging and a roughly 10x speedup in handling large prepl responses.

    I don’t have any particular plans for the future of this project - it was just something that I wanted to experiment with for a while. I see it as an interesting option for people looking for some middle ground between inf-clojure and CIDER.

    neat

    neat is the other new arrival: a small, language-agnostic nREPL client for Emacs. neat 0.1.0 has the essentials in place: a pure-elisp bencode codec, a comint-based REPL, and a source-buffer minor mode with eval, completion, eldoc, xref and doc lookup, tested against Clojure, Babashka and Basilisp. It’s early days, but it’s a nice testbed for exercising the nREPL protocol outside CIDER.

    This project also means I’ve dropped any plans to try to make CIDER a language-agnostic development environment. Going forward CIDER will focus only on Clojure-like languages, and everything else will be covered by neat.

    Piggieback and Weasel

    The nREPL org saw some ClojureScript-flavored action:

    • Piggieback 0.6.2 and Piggieback 0.7.0. The 0.7.0 release makes load-file evaluate the editor’s buffer contents instead of re-reading from disk, tears down ClojureScript REPLs when their sessions close (no more leaked Node processes) and surfaces ClojureScript status in the describe response.
    • Weasel 0.8.0 modernized the WebSocket REPL: the client now uses the platform’s native WebSocket, so it runs in any modern JavaScript runtime (browsers, Node 22+, Deno, Bun, workers), and the minimum requirements moved to Clojure/ClojureScript 1.12.

    I also backfilled proper GitHub releases for the historic tags of both projects, so their release history is finally browsable.

    Improving the ClojureScript support in CIDER has long been a major objective for me, and these small changes were some initial steps in that direction.

    refactor-nrepl and clj-refactor

    refactor-nrepl got three releases: 3.12.0, 3.13.0 and 3.14.0, the last one making the AST-based indexing much faster and more reliable. clj-refactor.el received a round of maintenance on master as well, and will get a new release after I wrap up the work on CIDER 2.0.

    I’m still pondering the future of both projects, as I plan to move the most useful refactor-nrepl features (those that don’t carry a lot of complexity) to CIDER and cider-nrepl eventually, and I’m not sure that the flagship AST-powered refactorings are very competitive these days (compared to clojure-lsp and static project-wide analysis a la clj-kondo in general).

    I’ll write a bit more about this and I’d certainly appreciate more feedback from the users of clj-refactor on the subject. It’s funny that I’ve been maintaining the project for ages, but I’ve never really used it (mostly due to its brittleness in the past). I think I managed to address some of the biggest problems recently, but perhaps this happened too late and the project has lost its relevance by now.

    Blog posts

    I wrote a few articles related to the work above:

    Wrapping up

    Big thanks to Clojurists Together, Nubank and the other organizations and people supporting my Clojure OSS work! I love you and none of this would have happened without you. Sadly, the amount of financial support my projects receive has eroded massively over the past 4 years and I’ve kind of lost hope that this negative trend will eventually be reversed. It was never easy to maintain many popular OSS projects, but the job certainly hasn’t got any easier or more rewarding in recent years…

    Overall, a super productive two months. Hopefully the next two are going to be just as productive, although I have to admit I’ve plucked most of the low-hanging fruit already. Then again, I’ve said this many times in the past, so one never knows…

  • Jul 4, 2026

    Projectile 3.1

    Hot on the heels of Projectile 3.0 comes Projectile 3.1!

    Three days apart, yes. There’s a story there. A big chunk of what’s in 3.1 was originally meant for 3.0, but 3.0 was already turning into a monster of a release and I decided to cut it into two, so I’d actually be able to reason about each of them. So think of 3.1 less as “the next release” and more as “the second half of 3.0 that I was too scared to ship all at once”.

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  • Jul 1, 2026

    Projectile 3.0

    Projectile 3.0 is finally out, and it’s a big one - easily the biggest release in years. There’s a nice reason for that: this year Projectile turns 15.1 It all started back in the summer of 2011, simply because I was frustrated that find-file-in-project didn’t work on Windows, and somehow that little anniversary made me want to shake things up and finally tackle a whole pile of changes I’d been putting off for ages. Some new features, some long-overdue spring cleaning, and a few things I’d wanted to remove for the better part of a decade.

    1. Give or take - I started Emacs Prelude the same year, so it’s always been a ↩

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  • Jul 1, 2026

    Sayid Redux

    I have a soft spot for Sayid - it’s one of the most ingenious Clojure tools ever built, and also one of the most neglected. It’s an omniscient debugger: instead of stopping your program at a breakpoint, it quietly records every call to the functions you’ve traced and lets you rummage through the recording afterwards. It’s the kind of thing you demo to people and watch their jaw drop. And it had been sitting practically unmaintained for the better part of a decade.

    Here’s the awkward part: that neglect is largely on me. Bill Piel, Sayid’s original author, handed me the keys ages ago, and I’ve been… let’s say a less than exemplary steward. I’d merge the occasional patch to keep the lights on, but until very recently I’d done precious little to actually move the project forward.

    The best time to maintain your open-source project was six years ago. The second best time is now.

    – Ancient proverb, lightly adapted

    So what finally lit a fire under me? Blame CIDER 2.0. I’ve been reworking CIDER’s debugging and tracing story, and at some point I sat down to make the built-in tracer smarter. A few hours in it hit me: nothing I could realistically bolt onto the built-in tracing would come anywhere close to what Sayid already does. So instead of building a worse Sayid, I dusted off the real one, gave it a good scrub, and here we are - Sayid 0.4.

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  • Jul 1, 2026

    nREPL and ClojureScript: Demystifying Piggieback

    I can’t carry it for you… but I can carry you!

    – Samwise Gamgee, on the virtues of piggyback

    If you’ve ever fired up a ClojureScript REPL from your editor and it just worked, there’s a decent chance Piggieback was quietly doing the heavy lifting behind the scenes. It’s one of those libraries that’s been around forever, that everyone in the CIDER world depends on, and that almost nobody actually understands. For years I counted myself firmly in the “almost nobody” camp.

    That changed recently. I finally had to do some serious work on Piggieback myself, and to my mild horror I realized I’d forgotten most of how it works internally. So I did what I always do when I need to understand something properly - I dug in, refactored it into a shape I could actually reason about, and then wrote it all down. This article is that write-up.

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