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53

Clojure macros continue to surprise me

from tonsky.me [alt+shift+b] in programming

Clojure macros have two modes: avoid them at all costs/do very basic stuff, or go absolutely crazy. Here’s the problem: I’m working on Humble UI’s component library, and I wanted to document it. While at it, I figured it could serve as an integration test as well—since I showcase every possible option, why not test it at the same time? This is what I came up with: I write component code, and in the application, I show a table with the running code on the left and the source on the right: It was important that code that I show is exactly the same code that I run (otherwise it wouldn’t be a very good test). Like a quine: hey program! Show us your source code! Simple with Clojure macros, right? Indeed: (defmacro table [& examples] (list 'ui/grid {:cols 2} (for [[_ code] (partition 2 examples)] (list 'list code (pr-str code))))) This macro accepts code AST and emits a pair of AST (basically a no-op) back and a string that we serialize that AST to. This is what I consider to be a “normal” macro usage. Nothing fancy, just another day at the office. Unfortunately, this approach reformats code: while in the macro, all we have is an already parsed AST (data structures only, no whitespaces) and we have to pretty-print it from scratch, adding indents and newlines. I tried a couple of existing formatters (clojure.pprint, zprint, cljfmt) but wasn’t happy with any of them. The problem is tricky—sometimes a vector is just a vector, but sometimes it’s a UI component and shows the structure of the UI. And then I realized that I was thinking inside the box all the time. We already have the perfect formatting—it’s in the source file! So what if... No, no, it’s too brittle. We shouldn’t even think about it... But what if... What if our macro read the source file? Like, actually went to the file system, opened a file, and read its content? We already have the file name conveniently stored in *file*, and luckily Clojure keeps sources around. So this is what I ended...
15th Jul 2024

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14th Jul 2026 • 1 votes
Every Frame Perfect

A while ago I was reading about Wayland and this quote stuck with me: A stated goal of Wayland is “every frame is perfect”. And I think this is a goal we should all aspire to. Wayland is talking about the technical side of things (modern GPU stacks are very complex and Wayland is trying to take control back) but it could be applied to UI too. The rule of thumb is: If I take a screenshot of your app at any moment, it must make sense Why care about every frame? It builds trust. Users can’t see the code, so UI is the only way for them to judge the quality of the app. If UI looks good, that means developers had time to polish it, which means that they probably spent a comparable amount of time to iron out the code. It’s a heuristic, but a reasonable one. Now, what does it mean in practice? I can think of a few things: No white flashes between screens. No partially loaded content. No relayout while content loads. Internally consistent. If one part of the UI says “1 update available”, another part should not say “Checking for updates...” Precise animations. Animations often end up being forgotten. A UI might look great in both start and end states but very janky in between. Like this: If you feel like there are weird things going on there, there are! Look at slowed down version: Now let’s apply our rule and take screenshots in the middle of the animation. This doesn’t look right: Neither does this: Both of these frames are not perfect. Let’s look at another example. Safari: Placeholder text here moves from the center but cursor animates from the left position: Not the end of the world by any means, but it does create a feeling that these two components are not in sync with each other. Next thought: maybe they weren’t designed together? If so, then they might not work well together. That’s how trust is lost. This desynchronization can lead to a lot of confusion. For example, in Photos, when switching between Crop and Adjust mode, picture snaps into place immediately but the crop border is animated: This creates a false feeling that something subtly changes when you switch between modes. And you know what? I don’t want my UI to give me false feelings. I want it to be a precise instrument, not an animated toy. Sometimes animations are supposed to help you understand a transition, so it’s doubly sad when they make it harder. Follow the magnifying glass: Same with Youtube. They had the simplest task in the world: move a rectangle from one position to another! Yet they decided to do something very strange: Can you explain this? Does it make sense? Probably a technical limitation of the DOM architecture they decided earlier on. I call these situations “The technology has outsmarted the programmer”. But no matter the reason, the result is an imperfect frame. Sometimes animations are left out as an afterthought. Whatever happens, happens. Then we get this: The details are fascinating to watch: So yeah. Please pay attention not only to the start and end states, but also to everything in between. Every frame matters. I’ll leave you with this unprovoked zoom animation from Preview app. Take care!

13th Jun 2026 • 1 votes
Claude is an Electron App because we’ve lost native

In “Why is Claude an Electron App?” Drew Breunig wonders: Claude spent $20k on an agent swarm implementing (kinda) a C-compiler in Rust, but desktop Claude is an Electron app. If code is free, why aren’t all apps native? And then argues that the answer is that LLMs are not good enough yet. They can do 90% of the work, so there’s still a substantial amount of manual polish, and thus, increased costs. But I think that’s not the real reason. The real reason is: native has nothing to offer. API-wise, native apps lost to web apps a long time ago. Native APIs are terrible to use, and OS vendors use everything in their power to make you not want to develop native apps for their platform. That explains the rise of Electron before LLM times, but it’s also a problem that LLMs solve now: if that was a real barrier to developing native apps, it doesn’t exist anymore. Then there’re looks and consistency. Some time ago, maybe in the late 90s and 2000s, native was ahead. It used to look good, it was consistent, and it all actually worked: the more apps used native look and feel, the better user experience was across apps (which we used to call programs). These days, though, native is as bad as the web, if not worse. Consistency is basically out the window. Anything can look like anything, buttons have no borders, contrast doesn’t exist, and neither do conventions. Apple, for example, seems to place traffic lights and corner radius by vibes rather than by any measurable guidelines. Maybe the server should round the corners? Looks could be good, but they also can be bad, and then you are stuck with platform-consistent, but generally bad UI (Liquid Glass ahem). It changes too often, too: the app you made today will look out of place next year, when Apple decides to change look and feel yet again. There’s no native look anymore. Computer UIs also degrade over time Theoretically, native apps can integrate with OS on a deeper level. This sounds nice, but what does that mean in practice? There are almost no good interoperable file formats; everything is locked inside individual apps, most services moved to the web, and OSes dropped the ball for making a good shared baseline. You can integrate with OS-provided calendar, but you can’t do it with web calendar. Well, you can, of course, but it’s easier on the web; native doesn’t help with it at all. Web pages only lead to more web pages Finally, the last hope of people longing for native is performance. They feel that native apps will be faster. Well, they can, but it doesn’t mean they will. Web apps can be faster, too, but in practice, nobody cares. There’s no technical reason why Slack needs to load 80 MiB just to show 10 channel names and 3 messages on a screen. The web is not the problem here! It’s a choice to be bad. What makes you think it’ll be different once the company decides to move to native? Don’t get me wrong: writing this brings me no joy. I don’t think web is a solution either. I just remember good times when native did a better-than-average job, and we were all better for using it, and it saddens me that these times have passed. I just don’t think that kidding ourselves that the only problem with software is Electron and it all will be butterflies and unicorns once we rewrite Slack in SwiftUI is not productive. The real problem is a lack of care. And the slop; you can build it with any stack.

3rd Mar 2026 • 1 votes
It’s hard to justify Tahoe icons

I was reading Macintosh Human Interface Guidelines from 1992 and found this nice illustration: accompanied by explanation: Fast forward to 2025. Apple releases macOS Tahoe. Main attraction? Adding unpleasant, distracting, illegible, messy, cluttered, confusing, frustrating icons (their words, not mine!) to every menu item: Sequoia → Tahoe It’s bad. But why exactly is it bad? Let’s delve into it! Disclaimer: screenshots are a mix from macOS 26.1 and 26.2, taken from stock Apple apps only that come pre-installed with the system. No system settings were modified. Icons should differentiate The main function of an icon is to help you find what you are looking for faster. Perhaps counter-intuitively, adding an icon to everything is exactly the wrong thing to do. To stand out, things need to be different. But if everything has an icon, nothing stands out. The same applies to color: black-and-white icons look clean, but they don’t help you find things faster! Microsoft used to know this: Look how much faster you can find Save or Share in the right variant: It also looks cleaner. Less cluttered. A colored version would be even better (clearer separation of text from icon, faster to find): I know you won’t like how it looks. I don’t like it either. These icons are hard to work with. You’ll have to actually design for color to look nice. But the principle stands: it is way easier to use. Consistency between apps If you want icons to work, they need to be consistent. I need to be able to learn what to look for. For example, I see a “Cut” command and next to it. Okay, I think. Next time I’m looking for “Cut,” I might save some time and start looking for instead. How is Tahoe doing on that front? I present to you: Fifty Shades of “New”: I even collected them all together, so the absurdity of the situation is more obvious. Granted, some of them are different operations, so they have different icons. I guess creating a smart folder is different from creating a journal entry. But this? Or this: Or this: There is no excuse. Same deal with open: Save: Yes. One of them is a checkmark. And they can’t even agree on the direction of an arrow! Close: Find (which is sometimes called Search, and sometimes Filter): Delete (from Cut-Copy-Paste-Delete fame): Minimize window. These are not some obscure, unique operations. These are OS basics, these are foundational. Every app has them, and they are always in the same place. They shouldn’t look different! Consistency inside the same app Icons are also used in toolbars. Conceptually, operations in a toolbar are identical to operations called through the menu, and thus should use the same icons. That’s the simplest case to implement: inside the same app, often on the same screen. How hard can it be to stay consistent? Preview: Photos: same and mismatch, but reversed ¯\_(ツ)_/¯ Maps and others often use different symbols for zoom: Icon reuse Another cardinal sin is to use the same icon for different actions. Imagine: I have learned that means “New”: Then I open an app and see. “Cool”, I think, “I already know what it means”: Gotcha! You’d think: okay, means quick look: Sometimes, sure. Some other times, means “Show completed”: Sometimes is “Import”: Sometimes is “Updates”: Same as with consistency, icon reuse doesn’t only happen between apps. Sometimes you see in a toolbar: Then go to the menu in the same app and see means something else: Sometimes identical icons meet in the same menu. Sometimes next to each other. Sometimes they put an entire barrage of identical icons in a row: This doesn’t help anyone. No user will find a menu item faster or will understand the function better if all icons are the same. The worst case of icon reuse so far has been the Photos app: It feels like the person tasked with choosing a unique icon for every menu item just ran out of ideas. Understandable. Too much nuance When looking at icons, we usually allow for slight differences in execution. That lets us, for example, understand that these technically different road signs mean the same thing: Same applies for icons: if you draw an arrow going out of the box in one place and also an arrow and the box but at a slightly different angle, or with different stroke width, or make one filled, we will understand them as meaning the same thing. Like, is supposed to mean something else from ? Come on! Or two-letter As that only slightly differ in the font size: A pencil is “Rename” but a slightly thicker pencil is “Highlight”? Arrows that use different diagonals? Three dots occupying ⅔ of space vs three dots occupying everything. Seriously? Slightly darker dots? The sheet of paper that changes meaning depending on if its corner is folded or if there are lines inside? But the final boss are arrows. They are all different: Supposedly, a user must become an expert at noticing how squished the circle is, if it starts top to right or bottom to right, and how far the arrow’s end goes. Do I care? Honestly, no. I could’ve given it a shot, maybe, if Apple applied these consistently. But Apple considers and to mean the same thing in one place, and expects me to notice minute details like this in another? Sorry, I can’t trust you. Not after everything I’ve seen. Detalization Icons are supposed to be easily recognizable from a distance. Every icon designer knows: small details are no-go. You can have them sometimes, maybe, for aesthetic purposes, but you can’t rely on them. And icons in Tahoe menus are tiny. Most of them fit in a 12×12 pixel square (actual resolution is 24×24 because of Retina), and because many of them are not square, one dimension is usually even less than 12. It’s not a lot of space to work with! Even Windows 95 had 16×16 icons. If we take the typical DPI of that era at 72 dots per inch, we get a physical icon size of 0.22 inches (5.6 mm). On a modern MacBook Pro with 254 DPI, Tahoe’s 24×24 icons are 0.09 inches (2.4 mm). Sure, 24 is bigger than 16, but in reality, these icons’ area is 4 times as small! Simulated physical size comparison between 16×16 at 72 DPI (left) and 24×24 at 254 DPI (right) So when I see this: I struggle. I can tell they are different. But I definitely struggle to tell what’s being drawn. Even zoomed in 20×, it’s still a mess: Or here. These are three different icons: Am I supposed to tell plus sign from sparkle here? Some of these lines are half the pixel thicker than the other lines, and that’s supposed to be the main point: Is this supposed to be an arrow? A paintbrush? Look, a tiny camera. It even got an even tinier viewfinder, which you can almost see if you zoom in 20×: Or here. There is a box, inside that box is a circle, and inside it is a tiny letter. i with a total height of 2 pixels: Don’t see it? I don’t. But it’s there... And this is a window! It even has traffic lights! How adorable: Remember: these are retina pixels, ¼ of a real pixel. Steve Jobs himself claimed they were invisible. It turns out there’s a magic number right around 300 pixels per inch, that when you hold something around to 10 to 12 inches away from your eyes, is the limit of the human retina to differentiate the pixels. And yet, Tahoe icons rely on you being able to see them. Pixel grid When you have so little space to work with, every pixel matters. You can make a good icon, but you have to choose your pixels very carefully. For Tahoe icons, Apple decided to use vector fonts instead of good old-fashioned bitmaps. It saves Apple resources—draw once, use everywhere. Any size, any display resolution, any font width. But there’re downsides: fonts are hard to position vertically, their size doesn’t map directly to pixels, stroke width doesn’t map 1-to-1 to pixel grid, etc. So, they work everywhere, but they also look blurry and mediocre everywhere: Tahoe icon (left) and its pixel-aligned version (right). They certainly start to work better once you give them more pixels. iPad OS 26 vs macOS 26 or make graphics simpler. But the combination of small details and tiny icon size is deadly. So, until Apple releases MacBooks with 380+ DPI, unfortunately, we still have to care about the pixel grid. Confusing metaphors Icons might serve another function: to help users understand the meaning of the command. For example, once you know the context (move window), these icons explain what’s going on faster than words: But for this to work, the user must understand what’s drawn on the icon. It must be a familiar object with a clear translation to computer action (like Trash can → Delete), a widely used symbol, or an easy-to-understand diagram. HIG: A rookie mistake would be to misrepresent the object. For example, this is how selection looks like: But its icon looks like this: Honestly, I’ve been writing this essay for a week, and I still have zero ideas why it looks like that. There’s an object that looks like this, but it’s a text block in Freeform/Preview: It’s called character.textbox in SF Symbols: Why did it become a metaphor for “Select all”? My best guess is it’s a mistake. Another place uses text selection from iOS as a metaphor. On a Mac! Some concepts have obvious or well-established metaphors. In that case, it’s a mistake not to use them. For example, bookmarks: . Apple, for some reason, went with a book: Sometimes you already have an interface element and can use it for an icon. However, try not to confuse your users. Dots in a rectangle look like password input, not permissions: Icon here says “Check” but the action is “Uncheck”. Terrible mistake: icon doesn’t help, it actively confuses the user. It’s also tempting to construct a two-level icon: an object and some sort of indicator. Like, a checkbox and a cross, meaning “Delete checkbox”: Or a user and a checkmark, like “Check the user”: Unfortunately, constructs like this rarely work. Users don’t build sentences from building blocks you provide; they have no desire to solve these puzzles. Finding metaphors is hard. Nouns are easier than verbs, and menu items are mostly verbs. How does open look? Like an arrow pointing to the top right? Why? I’m not saying there’s an obvious metaphor for “Open” Apple missed. There isn’t. But that’s the point: if you can’t find a good metaphor, using no icon is better than using a bad, confusing, or nonsensical icon. There’s a game I like to play to test the quality of the metaphor. Remove the labels and try to guess the meaning. Give it a try: It’s delusional to think that there’s a good icon for every action if you think hard enough. There isn’t. It’s a lost battle from the start. No amount of money or “management decisions” is going to change that. The problems are 100% self-inflicted. All this being said, I gotta give Apple credit where credit is due. When they are good at choosing metaphors, they are good: Symmetrical actions A special case of a confusing metaphor is using different metaphors for actions that are direct opposites of one another. Like Undo/Redo, Open/Close, Left/Right. It’s good when their icons use the same metaphor: Because it saves you time and cognitive resources. Learn one, get another one for free. Because of that, it’s a mistake not to use common metaphors for related actions: Or here: Another mistake is to create symmetry where there is none. “Back” and “See all”? Some menus in Tahoe make both mistakes. E.g. lack of symmetry between Show/Hide and false symmetry between completed/subtasks: Import not mirrored by Export but by Share: Text in icons HIG again: Authors of HIG are arguing against including text as a part of an icon. So something like this: or this: would not fly in 1992. I agree, but Tahoe has more serious problems: icons consisting only of text. Like this: It’s unclear where “metaphorical, abstract icon text that is not supposed to be read literally” ends and actual text starts. They use the same font, the same color, so how am I supposed to differentiate? Icons just get in a way: A...Complete? AaFont? What does it mean? I can maybe understand and . Dots are supposed to represent something. I can imagine thinking that led to . But ? No decorations. No effects. Just plain Abc. Really? Text transformations One might think that using icons to illustrate text transformations is a better idea. Like, you look at this: or this: or this: and just from the icon alone understand what will happen with the text. Icon illustrates the action. Also, BIU are well-established in word processing, so all upside? Not exactly. The problem is the same—text icon looks like text, not icon. Plus, these icons are excessive. What’s the point of taking the first letter and repeating it? The word “Bold” already starts with a letter “B”, it reads just as easily, so why double it? Look at it again: It’s also repeated once more as a shortcut... There is a better way to design this menu: And it was known to Apple for at least 33 years. System elements in icons Operating system, of course, uses some visual elements for its own purposes. Like window controls, resize handles, cursors, shortcuts, etc. It would be a mistake to use those in icons. Unfortunately, Apple fell into this trap, too. They reused arrows. Key shortcuts: HIG has an entire section on ellipsis specifically and how dangerous it is to use it anywhere else in the menu. And this exact problem is in Tahoe, too. Icons break scanning Without icons, you can just scan the menu from top to bottom, reading only the first letters. Because they all align: macOS Sequoia In Tahoe, though, some menu items have icons, some don’t, and they are aligned differently: Some items can have both checkmarks and icons, or have only one of them, or have neither, so we get situations like this: Ugh. Special mention This menu deserves its own category: Same icon for different actions. Missing the obvious metaphor. Somehow making the first one slightly smaller than the second and third. Congratulations! It got it all. Is HIG still relevant? I’ve been mentioning HIG a lot, and you might be wondering: is an interface manual from 1992 still relevant today? Haven’t computers changed so much that entirely new principles, designs, and idioms apply? Yes and no. Of course, advice on how to adapt your icons to black-and-white displays is obsolete. But the principles—as long as they are good principles—still apply, because they are based on how humans work, not how computers work. Humans don’t get a new release every year. Our memory doesn’t double. Our eyesight doesn’t become sharper. Attention works the same way it always has. Visual recognition, motor skills—all of this is exactly as it was in 1992. So yeah, until we get a direct chip-to-brain interface, HIG will stay relevant. Conclusion In my opinion, Apple took on an impossible task: to add an icon to every menu item. There are just not enough good metaphors to do something like that. But even if there were, the premise itself is questionable: if everything has an icon, it doesn’t mean users will find what they are looking for faster. And even if the premise was solid, I still wish I could say: they did the best they could, given the goal. But that’s not true either: they did a poor job consistently applying the metaphors and designing the icons themselves. I hope this article would be helpful in avoiding common mistakes in icon design, which Apple managed to collect all in one OS release. I love computers, I love interfaces, I love visual communication. It makes me sad seeing perfectly good knowledge already accessible 30 years ago being completely ignored or thrown away today. On the upside: it’s not that hard anymore to design better than Apple! Let’s drink to that. Happy New year! From SF Symbols: a smiley face calling somebody on the phone Notes During review of this post I was made familiar with Jim Nielsen’s article, which hits a lot of the same points as I do. I take that as a sign there’s some common truth behind our reasoning. Also note: Safari → File menu got worse since 26.0. Used to have only 4 icons, now it’s 18! Thanks Kevin, Ryan, and Nicki for reading drafts of this post.

5th Jan 2026 • 1 votes
Statistics made simple

I have a weird relationship with statistics: on one hand, I try not to look at it too often. Maybe once or twice a year. It’s because analytics is not actionable: what difference does it make if a thousand people saw my article or ten thousand? I mean, sure, you might try to guess people’s tastes and only write about what’s popular, but that will destroy your soul pretty quickly. On the other hand, I feel nervous when something is not accounted for, recorded, or saved for future reference. I might not need it now, but what if ten years later I change my mind? Seeing your readers also helps to know you are not writing into the void. So I really don’t need much, something very basic: the number of readers per day/per article, maybe, would be enough. Final piece of the puzzle: I self-host my web projects, and I use an old-fashioned web server instead of delegating that task to Nginx. Static sites are popular and for a good reason: they are fast, lightweight, and fulfil their function. I, on the other hand, might have an unfinished gestalt or two: I want to feel the full power of the computer when serving my web pages, to be able to do fun stuff that is beyond static pages. I need that freedom that comes with a full programming language at your disposal. I want to program my own web server (in Clojure, sorry everybody else). Existing options All this led me on a quest for a statistics solution that would uniquely fit my needs. Google Analytics was out: bloated, not privacy-friendly, terrible UX, Google is evil, etc. What is going on? Some other JS solution might’ve been possible, but still questionable: SaaS? Paid? Will they be around in 10 years? Self-host? Are their cookies GDPR-compliant? How to count RSS feeds? Nginx has access logs, so I tried server-side statistics that feed off those (namely, Goatcounter). Easy to set up, but then I needed to create domains for them, manage accounts, monitor the process, and it wasn’t even performant enough on my server/request volume! My solution So I ended up building my own. You are welcome to join, if your constraints are similar to mine. This is how it looks: It’s pretty basic, but does a few things that were important to me. Setup Extremely easy to set up. And I mean it as a feature. Just add our middleware to your Ring stack and get everything automatically: collecting and reporting. (def app (-> routes ... (ring.middleware.params/wrap-params) (ring.middleware.cookies/wrap-cookies) ... (clj-simple-stats.core/wrap-stats))) ;; <-- just add this It’s zero setup in the best sense: nothing to configure, nothing to monitor, minimal dependency. It starts to work immediately and doesn’t ask anything from you, ever. See, you already have your web server, why not reuse all the setup you did for it anyway? Request types We distinguish between request types. In my case, I am only interested in live people, so I count them separately from RSS feed requests, favicon requests, redirects, wrong URLs, and bots. Bots are particularly active these days. Gotta get that AI training data from somewhere. RSS feeds are live people in a sense, so extra work was done to count them properly. Same reader requesting feed.xml 100 times in a day will only count as one request. Hosted RSS readers often report user count in User-Agent, like this: Feedly/1.0 (+http://www.feedly.com/fetcher.html; 457 subscribers; like FeedFetcher-Google) Mozilla/5.0 (compatible; BazQux/2.4; +https://bazqux.com/fetcher; 6 subscribers) Feedbin feed-id:1373711 - 142 subscribers My personal respect and thank you to everybody on this list. I see you. Graphs Visualization is important, and so is choosing the correct graph type. This is wrong: Continuous line suggests interpolation. It reads like between 1 visit at 5am and 11 visits at 6am there were points with 2, 3, 5, 9 visits in between. Maybe 5.5 visits even! That is not the case. This is how a semantically correct version of that graph should look: Some attention was also paid to having reasonable labels on axes. You won’t see something like 117, 234, 10875. We always choose round numbers appropriate to the scale: 100, 200, 500, 1K etc. Goes without saying that all graphs have the same vertical scale and syncrhonized horizontal scroll. Insights We don’t offer much (as I don’t need much), but you can narrow reports down by page, query, referrer, user agent, and any date slice. Not implemented (yet) It would be nice to have some insights into “What was this spike caused by?” Some basic breakdown by country would be nice. I do have IP addresses (for what they are worth), but I need a way to package GeoIP into some reasonable size (under 1 Mb, preferably; some loss of resolution is okay). Finally, one thing I am really interested in is “Who wrote about me?” I do have referrers, only question is how to separate signal from noise. Performance. DuckDB is a sport: it compresses data and runs column queries, so storing extra columns per row doesn’t affect query performance. Still, each dashboard hit is a query across the entire database, which at this moment (~3 years of data) sits around 600 MiB. I definitely need to look into building some pre-calculated aggregates. One day. How to get Head to github.com/tonsky/clj-simple-stats and follow the instructions: Let me know what you think! Is it usable to you? What could be improved? P.S. You can try the live example at tonsky.me/stats. The data was imported from Nginx access logs, which I turned on and off on a few occasions, so it’s a bit spotty. Still, it should give you a general idea.

15th Dec 2025 • 1 votes

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3 hours ago • 1 votes
BazelCon 2026 recap

My now-traditional “summary” of the conference along with my own commentary and thoughts.

yesterday • 1 votes
The Future of CSS ✨

Every year, browser vendors collaborate via the Interop project to synchronize their efforts on new HTML/CSS/JS features. This year, there’s a ton of super exciting features being considered! In this blog post, we’ll explore the CSS of the future, to get a glimpse of what we’ll soon be able to do.

2 days ago • 1 votes
Speeding up code review with `small-change`

Imprint’s average engineer is merging 4x more PRs than 2 years ago. Yay. Aggregated behind the average is something even more interesting: we have two teams that are merging 10x their PRs over that period. One engineer is merging 25x the PRs per week of our average engineer two years ago, and a number are merging 10x. That’s pretty neat, and the slope of the line suggests our average in a year is going to look much closer to today’s p90 than today’s p50. Even more importantly, we aren’t just shipping more, our quality has improved: incidents are down 42% half-over-half, and critical incidents are down 78% half-over-half. I think we’ve always known the quality/velocity tradeoff wasn’t a particularly useful construct, but that’s undeniable today. As we’ve walked this path, we–like everyone else progressing down it–have run into the problem of pull request review. The p50 pull request review took about 33 minutes to complete 2 years ago, but now takes us about 77 minutes. The slope here correlates tightly with the number of pull requests getting merged. Tightly enough that addressing it became one of my priorities for the week. We solved it! Just kidding, we’ve absolutely not solved it, but I think our current approach is an interesting one, which we call the small-change. The work discussed here was shaped and done by many folks at Imprint including Dan, Joy, Daniel, Lenny, Taylor, Ted, and Annie, among many others. Why review pull requests? There are four reasons we review pull requests: Knowledge sharing between author and reviewer – software engineering is generally learned via apprenticeship, and reviews are a primary mechanism of experienced engineers teaching others what good software looks like. We believe the current volume means that this knowledge sharing will have to move towards operating on clusters of pull requests, rather than individual pull requests Preventing errors – review has always been an expensive time to catch errors, and we believe that effective CICD along with harness verification techniques like poteto’s pstack are more effective mechanisms for preventing errors than review Preventing malicious behavior – my experience is that even careful code review will generally miss competent malicious behavior, although fortunately most malicious behavior is incompetent. We believe both sorts of behavior are best identified using a combination of fixed rules (modifying these specific objects/classes/files requires review), anti-abuse mechanisms that we’ve refined in our LLM-based member support experiences, auditing, and audit log inspection Compliance obligations in our documented controls – these can be changed, but today they require that an independent human reviews changes in a subset of our repositories In the modern development paradigm, we think there is a better solution for each of these problems. But, we also want to make these changes very cautiously. Small steps with small-change We believe we move fast by finding narrow, contained ways to validate new practices, so to iterate our way into an effective solution, we’ve developed the concept of a small-change. Here’s how it works: When a pull request is marked ready, CICD determines whether it is eligible to be a small-change. This is represented as a passing Github check. There is also a label for visibility, but it is the check itself, managed by the build and not human modifiable, that determines eligibility. (The label is used for initial filtering, but the check is still independently verified.) Something is a small-change if it meets all of these criteria: It is less than 1,000 lines of code There are no p1 or p2 findings from our ai-code-review automated review bot The author has “experience” in the service or application, defined as 10+ prior merged pull requests into that service or application’s directories. For changes working across multiple services or applications, the author must have experience in all of them to qualify Impacts fewer than N distinct services or applications. N is 1 on our frontend monorepo, and N is 3 in our backend monorepo, where typical changes will modify both a gRPC service and a common HTTP gateway Shared libraries and utilities files are not eligible for small-change Each repository has a .small_change file which allows per-path customization while we continue to tune the behaviors. For example, a service dealing with money movement can be excluded Our Slack automation tags every reference to a pull request with reacji labeling the state of that pull request, for example if it has failing tests, if it has been approved but tests are still running, or if it is ready to merge. We added a small-change reacji that indicates which of those pull requests meet the small-change criteria In our internal skills repository, we created two skills that have been distributed across harnesses: review-small-change which takes a list of repositories and reviews all open, non-draft, small-changes, including providing approval if they meet the review’s criteria (all checks pass including small-change check, and not touching on sensitive topics such as payments and security) review-pr-cluster which reviews batches of pull requests to identify common themes that came up, and suggest opportunities for discussion and adding verifications We set the social expectation that any error caused by a small-change is a failure in our system, and has to be solved at the system level: improvements to ai-code-review, to our verification mechanisms, to our CICD, to our harness, etc. This took about two days of infrequent attention to implement and rollout, although I imagine we will be tuning the knobs here for a long time. Maybe forever. fleet: centrally orchestrated harness I’ll briefly mention our other approach to reducing code review volume, which anchors on our centrally-orchestrated harness, fleet. (Which is similar to Stripe’s Minions although not following the one-shot approach in particular). We rely on fleet to implement and verify software in a highly controlled harness running in the cloud, with independent evaluation mechanisms to identify the correct number of independent reviewers for any given change. That number can be as low as one (e.g. fleet writes, one human reviews) for changes evaluated as safe. Results / next steps / reception I’ll be honest, it’s too early to give a useful result here. From early results, about 10% of changes qualify as a small-change. Those are now eligible for very fast approval, and generally get it unless they trip a flag, generally due to touching a security or money adjacent topic. While 10% is a small percentage, the core concept here is working, and ultimately will succeed or fail based on our ability to expand that percentage over the next few months in tandem with expanding our verification mechanisms to be increasingly comprehensive. This is ultimately going to fail or succeed depending on our ability to improve our verifications, which does require more difficult sorts of techniques to accomplish in low scale-complexity, high domain-complexity software than in the high scale-complexity, low domain-complexity products where many techniques like incremental rollouts are exceptionally effective. (Don’t get me wrong, they still work, they just provide less coverage when most users have different configuration and behavior.) Folks have not been uniformly excited about this, it’s a substantial change from how we’ve learned to be good engineers, and it’s uncomfortable to reevaluate whether a long-held best practice has become merely dogma. The most energizing part of the current cycle is that we get to reevaluate these practices we grew up on every week; the most painful part of the current cycle is that we’re likely to fall behind if we ever stop reevaluating them.

5 days ago • 1 votes
Building a Chestnut Launcher

The park near my house has lots of chestnuts and my kids have been collecting them like crazy (it’s actually their favorite post-school activity). We accumulated quite a hoard. I thought it would be fun to make a launcher so we had something to do with our new chestnut collection. I wanted to go with a very simple crossbow-style design (like the famous D2 item) using latex tubing and a leather pouch for holding the chestnuts. This is what I came up with. It launches chestnuts about 220 feet, and it’s simple enough to build in an afternoon. The frame is a 42 inch 2x2 and a spare IKEA bed slat for the crossbeam, glued and screwed together. A 3/8 inch eye bolt goes through each end of the crossbeam, and the latex tubing is tied to those and to the pouch from a leather shepherd’s sling. Tying the tubing was the fiddliest part. It has to be stretched while you wrap it with butcher’s twine, so I clamped a couple of scrap blocks to my workbench to hold it. I like this design because the tubing can be wrapped around the eye bolts to easily add more tension and power. The Trigger My favorite part of the design was that I decided to use an archery release like this one for the trigger. It provides a safe and reliable way to hold the tubing back, and it’s made to let go cleanly. I 3D printed a little housing that mounts the release securely to the back of the stock, and the release clips onto a loop of archery D-loop cord on the back of the pouch. Then I added a dowel for a rear grip and an old handle I had previously removed from my shop vac. How Well Does It Work? We tried it at the park and it works surprisingly well. Aimed at about 35 to 40 degrees, it sends our chestnuts (on the small side, about 10 to 15 grams) about 220 feet. Thanks to the archery release, we haven’t had a single misfire. I got curious and did some rough math. To go that far with air drag, the chestnuts are leaving at somewhere around 85 to 100 mph, which works out to about the same energy as a paintball. So safety glasses are important and you never point it at anyone. You can find the 3D print on Printables and a full build guide on Instructables. Make sure to always use it with adult supervision :)

5 days ago • 1 votes
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