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In 2016, I wrote Productivity in the age of hypergrowth to discuss the challenges of engineering management during periods of hypergrowth. Managers in such periods spend much of their time on hiring and onboarding, with the remainder devoted to organizational structure and high-level strategy. Their technical expertise is important, but it’s demonstrated indirectly in the quality of their strategy, structure, and hiring. In 2023, our universe has shifted. There’s little hiring happening, and most companies are eliminating roles to meet investor and market pressure to operate in an environment where fundraising new cash is significantly more expensive. The role of engineering management has changed as well. Hiring and onboarding are now secondary components of our work, strategy and structure are elevated, and there’s a demand for us to employ our technical expertise more directly. My experience is that this shift is real, has been relatively subtle, and hasn’t really been directly...
over a year ago

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More from Irrational Exuberance

What is the competitive advantage of authors in the age of LLMs?

Over the past 19 months, I’ve written Crafting Engineering Strategy, a book on creating engineering strategy. I’ve also been working increasingly with large language models at work. Unsurprisingly, the intersection of those two ideas is a topic that I’ve been thinking about a lot. What, I’ve wondered, is the role of the author, particularly the long-form author, in a world where an increasingly large percentage of writing is intermediated by large language models? One framing I’ve heard somewhat frequently is the view that LLMs are first and foremost a great pillaging of authors’ work. It’s true. They are that. At some point there was a script to let you check which books had been loaded into Meta’s LLaMa, and every book I’d written at that point was included, none of them with my consent. However, I long ago made my peace with plagiarism online, and this strikes me as not particularly different, albeit conducted by larger players. The folks using this writing are going to keep using it beyond the constraints I’d prefer it to be used in, and I’m disinterested in investing my scarce mental energy chasing through digital or legal mazes. Instead, I’ve been thinking about how this transition might go right for authors. My favorite idea that I’ve come up with is the idea of written content as “datapacks” for thinking. Buy someone’s book / “datapack”, then upload it into your LLM, and you can immediately operate almost as if you knew the book’s content. Let’s start with an example. Imagine you want help onboarding as an executive, and you’ve bought a copy of The Engineering Executive’s Primer, you could create a project in Anthropic’s Claude, and upload the LLM-optimized book into your project. Here is what your Claude project might look like. Once you have it set up, you can ask it to help you create your onboarding plan. This guidance makes sense, largely pulled from Your first 90 days as CTO. As always, you can iterate on your initial prompt–including more details you want to include into the plan–along with follow ups to improve the formatting and so on. One interesting thing here, is that I don’t currently have a datapack for The Engineering Executive’s Primer! To solve that, I built one from all my blog posts marked with the “executive” tag. I did that using this script that packages Hugo blog posts, that I generated using this prompt with Claude 3.7 Sonnet. The output of that script gets passed into repomix via: repomix --include "`./scripts/tags.py content executive | paste -d, -s -`" The mess with paste is to turn the multiline output from tags.py into a comma-separated list that repomix knows how to use. This is a really neat pattern, and starts to get at where I see the long-term advantage of writers in the current environment: if you’re a writer and have access to your raw content, you can create a problem-specific datapack to discuss the problem. You can also give that datapack to someone else, or use it to answer their questions. For example, someone asked me a very detailed followup question about a recent blog post. It was a very long question, and I was on a weekend trip. I already had a Claude project setup with the contents of Crafting Engineering Strategy, so I just passed the question verbatim into that project, and sent the answer back to the person who asked it. (I did have to ask Claude to revise the answer once to focus more on what I thought the most important part of the answer was.) This, for what it’s worth, wasn’t a perfect answer, but it’s pretty good. If the question asker had the right datapack, they could have gotten it themselves, without needing me to decide to answer it. However, this post is less worried about the reader than it is about the author. What is our competitive advantage as authors in a future where people are not reading our work? Well, maybe they’re still buying our work in the form of datapacks and such, but it certainly seems likely that book sales, like blog traffic, will be impacted negatively. In trade, it’s now possible for machines to understand our thinking that we’ve recorded down into words over time. There’s a running joke in my executive learning circle that I’ve written a blog post on every topic that comes up, and that’s kind of true. That means that I am on the cusp of the opportunity to uniquely scale myself by connecting “intelligence on demand for a few cents” with the written details of my thinking built over the past two decades of being a writer who operates. The tools that exist today are not quite there yet, although a combination of selling datapacks like the one for Crafting Engineering Strategy and tools like Claude’s projects are a good start. There are many ways the exact details might come together, but I’m optimistic that writing will become more powerful rather than less in this new world, even if the particular formats change. (For what it’s worth, I don’t think human readers are going away either.) If you’re interested in the fully fleshed out version of this idea, starting here you can read the full AI Companion to Crafting Engineering Strategy. The datapack will be available via O’Reilly in the next few months. If you’re an existing O’Reilly author who’s skepical of this idea, don’t worry: I worked with them to sign a custom contract, this usage–as best I understood it, although I am not a lawyer and am not providing legal advice–is outside of the scope of the default contract I signed with my prior book, and presumably most others’ contracts as well.

2 weeks ago 13 votes
My desk setup in 2025.

Since 2020, I’ve been working on my desk setup, and I think I finally have it mostly pulled together at this point. I don’t really think my desk setup is very novel, and I’m sure there are better ways to pull it together, but I will say that it finally works the way I want since I added the CalDigit TS5 Plus, which has been a long time coming. My requirements for my desk are: Has support for 2-3 Mac laptops Has support for a Windows gaming desktop with a dedicated GPU Has a dedicated microphone Has good enough lighting Is not too messy I can switch between any laptop and desktop with a single Thunderbolt cable Historically the issue here has been the final requirement, where switching required moving two cables–a Thunderbolt and a cable for the dedicated graphics card–but with my new dock this finally works with just one cable. The equipment shown here, and my brief review of each piece, is: UPLIFT v2 Standing Desk – is the standing desk I use. I both have a lot of stuff on my desk, and also want my desk to feel minimal, so I opted for the 72" x 30" verison. At the time I ordered it in 2020, the only option shipping quickly was the bamboo finish, so that’s what I got. CalDigit TS5 Plus Dock – this was the missing component that has three Thunderbolt ports and a DisplayPort. I have the external graphics card directly connected to the DisplayPort, and then move the Thunderbolt port from computer to computer to change which one is active. It also has enough USB-A ports to connect the adapters for my wireless keyboard and mouse, to avoid needing to pair them across computers which would create friction in switching computers. Apple Studio Display – I experimented with dedicated speakers and video camera, but for me having them built into the monitor was helpful to reduce the number of things on my desk. The Studio Display’s monitor, speakers and video camera are all solidly good enough for my purposes: I’m sure I could get better on each dimension, but in practice I never think about this and don’t find any issues with them. On the other hand, while I was initially hopeful that I could also get rid of my microphone, the microphone quality just wasn’t that good for me, as I spend a lot of time on video conferences and recording podcasts, etc. Beelink GTi Ultra & EX Pro Docking Station – are my Windows mini desktop and dock which allows mounting an external GPU to the mini desktop. Beelink itself is slightly aggrevating because as best I can tell they’ve done something quite odd in terms of custom patching Windows 11, but ultimately it’s worked well for me as a dedicated gaming machine, and the build quality and size profile are both just fantastic. MSI Gaming RTX 4070 Ti Super 16G Graphics Card – I bought this earlier this year, looking for something that was in stock, and was good enough that it would last me a generation or two of graphics card upgrades without shelling out a truly massive amount for a 50XX edition (some of which don’t seem to be upgrades on the 40XX predecesors anyway). Hexcal Studio – this is the workstation / monitor stand / cable management system, with lighting and so on. I ultimately do like this, but it’s not perfect, e.g. my Qi charger technically works but provides such bad charging speeds that it effectively doesn’t work. It’s definitely too expensive for something that doesn’t entirely work, so I can’t really recommend it, although now that I’ve paid for it, I wouldn’t bother replacing it either. Audio-Technica AT2020USB Cardioid Condenser USB Microphone – this is the microphone I’ve been using for six years, and it’s really quite good and cost something like $120 at the time. It’s discontinued now, but presumably there’s a more modern version somewhere. I have it mounted on this boom arm. LUME CUBE Edge 2.0 LED Desk Lamp – I have two of these for lighting during recordings. I don’t actually like using them very much, I just hate looking into lights, but I do use them periodically when I want to make sure lighting is actually correct. Logitech MX Keys Advanced Wireless Illuminated Keyboard for Mac – this keyboard works well for me, and has a USB-C so I can use a single powered USB-C cable from the Hexcal to charge my keyboard, my mouse, my phone, and my headphones. Logitech MX Master 3S Wireless Mouse – I’ve been using variations of this mouse for a long time, I specifically bought this version a year or two ago to standardize all charging ports on USB-C. Laptop stand – I’m not actually sure where I got this laptop stand from, it might have been Etsy. I found it relatively hard to find stands that support three laptops rather than just two. Before finding this one, I used this two-laptop stand which is fine. Laptops – these are my personal and work Macbooks. Here’s a slightly closer look at the left side of the desk. At this point, I really have nothing left that I’m upset about with my setup, and I can’t imagine changing this again in the next few years. As a bonus, my office has a handful of pieces of “professional art” that represent things I am proud of. From left to right, it’s the cover of An Elegant Puzzle, a map of San Francisco drawn exclusively from Uber trip data on the night of Halloween 2014, and then the cover of The Engineering Executive’s Primer. It’s probably a bit vain, but I like to remember some of the accomplishments.

3 weeks ago 16 votes
Stuff I learned at Carta.

Today’s my last day at Carta, where I got the chance to serve as their CTO for the past two years. I’ve learned so much working there, and I wanted to end my chapter there by collecting my thoughts on what I learned. (I am heading somewhere, and will share news in a week or two after firming up the communication plan with my new team there.) The most important things I learned at Carta were: Working in the details – if you took a critical lens towards my historical leadership style, I think the biggest issue you’d point at is my being too comfortable operating at a high level of abstraction. Utilizing the expertise of others to fill in your gaps is a valuable skill, but–like any single approach–it’s limiting when utilized too frequently. One of the strengths of Carta’s “house leadership style” is expecting leaders to go deep into the details to get informed and push pace. What I practiced there turned into the pieces on strategy testing and developing domain expertise. Refining my approach to engineering strategy – over the past 18 months, I’ve written a book on engineering strategy (posts are all in #eng-strategy-book), with initial chapters coming available for early release with O’Reilly next month. Fingers crossed, the book will be released in approximately October. Coming into Carta, I already had much of my core thesis about how to do engineering strategy, but Carta gave me a number of complex projects to practice on, and excellent people to practice with: thank you to Dan, Shawna and Vogl in particular! More on this project in the next few weeks. Extract the kernel – everywhere I’ve ever worked, teams have struggled understanding executives. In every case, the executives could be clearer, but it’s not particularly interesting to frame these problems as something the executives need to fix. Sure, that’s true they could communicate better, but that framing makes you powerless, when you have a great deal of power to understand confusing communication. After all, even good communicators communicate poorly sometimes. Meaningfully adopting LLMs – a year ago I wrote up notes on adopting LLMs in your products, based on what we’d learned so far. Since then, we’ve learned a lot more, and LLMs themselves have significantly improved. Carta has been using LLMs in real, business-impacting workflows for over a year. That’s continuing to expand into solving more complex internal workflows, and even more interestingly into creating net-new product capabilities that ought to roll out more widely in the next few months (currently released to small beta groups). This is the first major technology transition that I’ve experienced in a senior leadership role (since I was earlier in my career when mobile internet transitioned from novelty to commodity). The immense pressure to adopt faster, combined with the immense uncertainty if it’s a meaningful change or a brief blip was a lot of fun, and was the inspiration for this strategy document around LLM adoption. Multi-dimensional tradeoffs – a phrase that Henry Ward uses frequent is that “everyone’s right, just at a different altitude.” That idea resonates with me, and meshes well with the ideas of multi-dimensional tradeoffs and layers of context that I find improve decision making for folks in roles that require making numerous, complex decisions. Working at Carta, these ideas formalized from something I intuited into something I could explain clearly. Navigators – I think our most successful engineering strategy at Carta was rolling out the Navigator program, which ensured senior-most engineers had context and direct representation, rather than relying exclusively on indirect representation via engineering management. Carta’s engineering managers are excellent, but there’s always something lost as discussions extend across layers. The Navigator program probably isn’t a perfect fit for particularly small companies, but I think any company with more than 100-150 engineers would benefit from something along these lines. How to create software quality – I’ve evolved my thinking about software quality quite a bit over time, but Carta was particularly helpful in distinguishing why some pieces of software are so hard to build despite having little-to-no scale from a data or concurrency perspective. These systems, which I label as “high essential complexity”, deserve more credit for their complexity, even if they have little in the way of complexity from infrastructure scaling. Shaping eng org costs – a few years ago, I wrote about my mental model for managing infrastructure costs. At Carta, I got to refine my thinking about engineering salary costs, with most of those ideas getting incorporated in the Navigating Private Equity ownership strategy, and the eng org seniority mix model. The three biggest levers are (1) “N-1 backfills”, (2) requiring a business rationale for promotions into senior-most levels, and (3) shifting hiring into cost efficient hiring regions. None of these are the sort of inspiring topics that excite folks, but they are all essential to the long term stability of your organization. Explaining engineering costs to boards/execs – Similarly, I finally have a clear perspective on how to represent R&D investment to boards in the same language that they speak in, which I wrote up here, and know how to do it quickly without relying on any manually curated internal datasets. Lots of smaller stuff, like the no wrong doors policy for routing colleagues to appropriate channels, how to request headcount in a way that is convincing to executives, Act Two rationales for how people’s motivations evolve over the course of long careers (and my own personal career mission to advance the industry, why friction isn’t velocity even though many folks act like it is. I’ve also learned quite a bit about venture capital, fund administration, cap tables, non-social network products, operating a multi-business line company, and various operating models. Figuring out how to sanitize those learnings to share the interesting tidbits without leaking internal details is a bit too painful, so I’m omitting them for now. Maybe some will be shareable in four or five years after my context goes sufficiently stale. As a closing thought, I just want to say how much I’ve appreciated the folks I’ve gotten to work with at Carta. From the executive team (Ali, April, Charly, Davis, Henry, Jeff, Nicole, Vrushali) to my directs (Adi, Ciera, Dan, Dave, Jasmine, Javier, Jayesh, Karen, Madhuri, Sam, Shawna) to the navigators (there’s a bunch of y’all). The people truly are always the best part, and that was certainly true at Carta.

a month ago 20 votes
systems-mcp: generate systems models via LLM

Back in 2018, I wrote lethain/systems as a domain-specific language for writing runnable systems models, and introduced it with this blog post modeling a hiring funnel. While it’s far from a perfect system, I’ve gotten a lot of value out of it over the last seven years, because it allows me to maintain systems models in version control. As I’ve been playing with writing Model Context Protocol (MCP) servers, one I’ve been thinking about frequently is one to help writing systems syntax, and I finally put that together in the lethain/systems-mcp repository. More detailed installation and usage instructions are in the GitHub repository, so I’ll just share a couple of screenshots and comments here. Starting with the load_systems_documentation tool which loads a copy of lethain/systems/README.md and a file with example systems into the context window. The biggest challenge of properly writing DSLs with an LLM is providing enough in-context learning (ICL) examples, and I think the idea of providing tools that are specifically designed to provide that context is a very interesting idea. Eventually I imagine there will be generalized tools for this, e.g. a search index of the best ICL examples for a wide variety of DSLs. Until then, my guess is that this sort of tool is particularly valuable. The second tool is run_systems_model which passes the DSL (and an optional parameter for number of rounds) to the tool and then returns the result. I experimented with interface design here, initially trying to return a rendered chart of the results, but ultimately even multi-modal models are just much better at working with text than with images. This meant that I had the best results returning JSON of the results and then having the LLM build a tool for interacting with the results. Altogether, a fun little experiment, and another confirmation in my mind that the most interesting part of designing MCPs today is deciding where to introduce and eliminate complexity from the LLM. Introduce too little and the tool lacks power; eliminate too little and the combination rarely works.

a month ago 21 votes
How to provide feedback on documents.

At Carta, we recently ran a reading group for Facilitating Software Architecture by Andrew Harmel-Law. We already loosely followed the ideas of an architectural advice process (from this 2021 article by the same Andrew Harmel-Law), but in practice we found that internal tech spec and architecture decision record (ADR) authors tended to exclusively share their documents locally within their team rather than more widely. As we asked authors why they preferred sharing locally, the most common answer was that they got enough feedback from their team that they didn’t want to pay the time overhead of sharing widely. The wider feedback wasn’t necessarily bad or combative. It just wasn’t good enough to compensate for the additional time it cost to process. This made sense from the authors’ perspectives, but didn’t work well for me from the executive perspective, as I was seeing teams make misaligned decisions due to lack of cross-team communication. As one step in reducing the overhead of sharing documents widely, I wrote up and shared this recommended process for providing feedback on documents: Before starting, remember that the goal of providing feedback on a document is to help the author. Optimizing for anything else, even if it’s a worthy cause, discourages authors from sharing their future writing. If you prioritize something other than helping the author, you are discouraging them from sharing future work. Start by skimming the document to understand its structure and where various kinds of topics are addressed. Why? This helps avoid giving feedback on ways the document’s actual structure diverges from how you imagined it would be structured. It also reduces questions about topics that are answered later in the document. Both of these sorts of feedback are a distraction during a discussion on a tech spec. In general, it’s better to avoid them. If you notice an author making the same significant structural mistake over several ADRs, it’s worth delivering that feedback separately. After skimming, reread the document, leaving comments with concerns. Each comment should include these details: What your suggested change or concern is Why you believe this is meaningful to address How important this seems (from ignorable nitpick to critical) If you find yourself leaving more than three or four issues, then you should either raise your threshold for commenting or you should schedule time with the individual to talk over the feedback. If the document is unreasonably weak, then it’s appropriate to nudge their leadership to dig into what’s happening on that team. The most important idea behind these steps is that your goal as a feedback giver is to help the document’s author. It is not to protect your team’s strategy or platform. It is not to optimize for your goals. It’s to help the author. This might feel wrong, but ultimately optimizing for anything else will lead to an environment where sharing widely is an irrational behavior. As a final aside, I think the user experience around commenting on documents is fundamentally wrong in most document editors. For example, Google Docs treats individual comments as first-order objects, similarly to how old version control systems like CVS tracked changes to individual files without tracking an overall state of the project. Ultimately, you want to collect all your comments into a bundle, then review that bundle for consistency and duplicates, and then submit that bundle as commentary, but editors don’t support that flow particularly well.

a month ago 23 votes

More in programming

Digital hygiene: Emails

Email is your most important online account, so keep it clean.

16 hours ago 4 votes
Building a container orchestrator

Kubernetes is not exactly the most fun piece of technology around. Learning it isn’t easy, and learning the surrounding ecosystem is even harder. Even those who have managed to tame it are still afraid of getting paged by an ETCD cluster corruption, a Kubelet certificate expiration, or the DNS breaking down (and somehow, it’s always the DNS). Samuel Sianipar If you’re like me, the thought of making your own orchestrator has crossed your mind a few times. The result would, of course, be a magical piece of technology that is both simple to learn and wouldn’t break down every weekend. Sadly, the task seems daunting. Kubernetes is a multi-million lines of code project which has been worked on for more than a decade. The good thing is someone wrote a book that can serve as a good starting point to explore the idea of building our own container orchestrator. This book is named “Build an Orchestrator in Go”, written by Tim Boring, published by Manning. The tasks The basic unit of our container orchestrator is called a “task”. A task represents a single container. It contains configuration data, like the container’s name, image and exposed ports. Most importantly, it indicates the container state, and so acts as a state machine. The state of a task can be Pending, Scheduled, Running, Completed or Failed. Each task will need to interact with a container runtime, through a client. In the book, we use Docker (aka Moby). The client will get its configuration from the task and then proceed to pull the image, create the container and start it. When it is time to finish the task, it will stop the container and remove it. The workers Above the task, we have workers. Each machine in the cluster runs a worker. Workers expose an API through which they receive commands. Those commands are added to a queue to be processed asynchronously. When the queue gets processed, the worker will start or stop tasks using the container client. In addition to exposing the ability to start and stop tasks, the worker must be able to list all the tasks running on it. This demands keeping a task database in the worker’s memory and updating it every time a task change’s state. The worker also needs to be able to provide information about its resources, like the available CPU and memory. The book suggests reading the /proc Linux file system using goprocinfo, but since I use a Mac, I used gopsutil. The manager On top of our cluster of workers, we have the manager. The manager also exposes an API, which allows us to start, stop, and list tasks on the cluster. Every time we want to create a new task, the manager will call a scheduler component. The scheduler has to list the workers that can accept more tasks, assign them a score by suitability and return the best one. When this is done, the manager will send the work to be done using the worker’s API. In the book, the author also suggests that the manager component should keep track of every tasks state by performing regular health checks. Health checks typically consist of querying an HTTP endpoint (i.e. /ready) and checking if it returns 200. In case a health check fails, the manager asks the worker to restart the task. I’m not sure if I agree with this idea. This could lead to the manager and worker having differing opinions about a task state. It will also cause scaling issues: the manager workload will have to grow linearly as we add tasks, and not just when we add workers. As far as I know, in Kubernetes, Kubelet (the equivalent of the worker here) is responsible for performing health checks. The CLI The last part of the project is to create a CLI to make sure our new orchestrator can be used without having to resort to firing up curl. The CLI needs to implement the following features: start a worker start a manager run a task in the cluster stop a task get the task status get the worker node status Using cobra makes this part fairly straightforward. It lets you create very modern feeling command-line apps, with properly formatted help commands and easy argument parsing. Once this is done, we almost have a fully functional orchestrator. We just need to add authentication. And maybe some kind of DaemonSet implementation would be nice. And a way to handle mounting volumes…

20 hours ago 3 votes
clamp / median / range

Here are a few tangentially-related ideas vaguely near the theme of comparison operators. comparison style clamp style clamp is median clamp in range range style style clash? comparison style Some languages such as BCPL, Icon, Python have chained comparison operators, like if min <= x <= max: ... In languages without chained comparison, I like to write comparisons as if they were chained, like, if min <= x && x <= max { // ... } A rule of thumb is to prefer less than (or equal) operators and avoid greater than. In a sequence of comparisons, order values from (expected) least to greatest. clamp style The clamp() function ensures a value is between some min and max, def clamp(min, x, max): if x < min: return min if max < x: return max return x I like to order its arguments matching the expected order of the values, following my rule of thumb for comparisons. (I used that flavour of clamp() in my article about GCRA.) But I seem to be unusual in this preference, based on a few examples I have seen recently. clamp is median Last month, Fabian Giesen pointed out a way to resolve this difference of opinion: A function that returns the median of three values is equivalent to a clamp() function that doesn’t care about the order of its arguments. This version is written so that it returns NaN if any of its arguments is NaN. (When an argument is NaN, both of its comparisons will be false.) fn med3(a: f64, b: f64, c: f64) -> f64 { match (a <= b, b <= c, c <= a) { (false, false, false) => f64::NAN, (false, false, true) => b, // a > b > c (false, true, false) => a, // c > a > b (false, true, true) => c, // b <= c <= a (true, false, false) => c, // b > c > a (true, false, true) => a, // c <= a <= b (true, true, false) => b, // a <= b <= c (true, true, true) => b, // a == b == c } } When two of its arguments are constant, med3() should compile to the same code as a simple clamp(); but med3()’s misuse-resistance comes at a small cost when the arguments are not known at compile time. clamp in range If your language has proper range types, there is a nicer way to make clamp() resistant to misuse: fn clamp(x: f64, r: RangeInclusive<f64>) -> f64 { let (&min,&max) = (r.start(), r.end()); if x < min { return min } if max < x { return max } return x; } let x = clamp(x, MIN..=MAX); range style For a long time I have been fond of the idea of a simple counting for loop that matches the syntax of chained comparisons, like for min <= x <= max: ... By itself this is silly: too cute and too ad-hoc. I’m also dissatisfied with the range or slice syntax in basically every programming language I’ve seen. I thought it might be nice if the cute comparison and iteration syntaxes were aspects of a more generally useful range syntax, but I couldn’t make it work. Until recently when I realised I could make use of prefix or mixfix syntax, instead of confining myself to infix. So now my fantasy pet range syntax looks like >= min < max // half-open >= min <= max // inclusive And you might use it in a pattern match if x is >= min < max { // ... } Or as an iterator for x in >= min < max { // ... } Or to take a slice xs[>= min < max] style clash? It’s kind of ironic that these range examples don’t follow the left-to-right, lesser-to-greater rule of thumb that this post started off with. (x is not lexically between min and max!) But that rule of thumb is really intended for languages such as C that don’t have ranges. Careful stylistic conventions can help to avoid mistakes in nontrivial conditional expressions. It’s much better if language and library features reduce the need for nontrivial conditions and catch mistakes automatically.

2 hours ago 1 votes
Bugs I fixed in SumatraPDF

Unexamined life is not worth living said Socrates. I don’t know about that but to become a better, faster, more productive programmer it pays to examine what makes you un-productive. Fixing bugs is one of those un-productive activities. You have to fix them but it would be even better if you didn’t write them in the first place. Therefore it’s good to reflect after fixing a bug. Why did the bug happen? Could I have done something to not write the bug in the first place? If I did write the bug, could I do something to diagnose or fix it faster? This seems like a great idea that I wasn’t doing. Until now. Here’s a random selection of bugs I found and fixed in SumatraPDF, with some reflections. SumatraPDF is a C++ win32 Windows app. It’s a small, fast, open-source, multi-format PDF/eBook/Comic Book reader. To keep the app small and fast I generally avoid using other people’s code. As a result most code is mine and most bugs are mine. Let’s reflect on those bugs. TabWidth doesn’t work A user reported that TabWidth advanced setting doesn’t work in 3.5.2 but worked in 3.4.6. I looked at the code and indeed: the setting was not used anywhere. The fix was to use it. Why did the bug happen? It was a refactoring. I heavily refactored tabs control. Somehow during the rewrite I forgot to use the advanced setting when creating the new tabs control, even though I did write the code to support it in the control. I guess you could call it sloppiness. How could I not write the bug? I could review the changes more carefully. There’s no-one else working on this project so there’s no one else to do additional code reviews. I typically do a code review by myself with webdiff but let’s face it: reviewing changes right after writing them is the worst possible time. I’m biased to think that the code I just wrote is correct and I’m often mentally exhausted. Maybe I should adopt a process when I review changes made yesterday with fresh, un-tired eyes? How could I detect the bug earlier?. 3.5.2 release happened over a year ago. Could I have found it sooner? I knew I was refactoring tabs code. I knew I have a setting for changing the look of tabs. If I connected the dots at the time, I could have tested if the setting still works. I don’t make releases too often. I could do more testing before each release and at the very least verify all advanced settings work as expected. The real problem In retrospect, I shouldn’t have implemented that feature at all. I like Sumatra’s customizability and I think it’s non-trivial contributor to it’s popularity but it took over a year for someone to notice and report that particular bug. It’s clear it’s not a frequently used feature. I implemented it because someone asked and it was easy. I should have said no to that particular request. Fix printing crash by correctly ref-counting engine Bugs can crash your program. Users rarely report crashes even though I did put effort into making it easy. When I a crash happens I have a crash handler that saves the diagnostic info to a file and I show a message box asking users to report the crash and with a press of a button I launch a notepad with diagnostic info and a browser with a page describing how to submit that as a GitHub issue. The other button is to ignore my pleas for help. Most users overwhelmingly choose to ignore. I know that because I also have crash reporting system that sends me a crash report. I get thousands of crash reports for every crash reported by the user. Therefore I’m convinced that the single most impactful thing for making software that doesn’t crash is to have a crash reporting system, look at the crashes and fix them. This is not a perfect system because all I have is a call stack of crashed thread, info about the computer and very limited logs. Nevertheless, sometimes all it takes is a look at the crash call stack and inspection of the code. I saw a crash in printing code which I fixed after some code inspection. The clue was that I was accessing a seemingly destroyed instance of Engine. That was easy to diagnose because I just refactored the code to add ref-counting to Engine so it was easy to connect the dots. I’m not a fan of ref-counting. It’s easy to mess up ref-counting (add too many refs, which leads to memory leaks or too many releases which leads to premature destruction). I’ve seen codebases where developers were crazy in love with ref-counting: every little thing, even objects with obvious lifetimes. In contrast,, that was the first ref-counted object in over 100k loc of SumatraPDF code. It was necessary in this case because I would potentially hand off the object to a printing thread so its lifetime could outlast the lifetime of the window for which it was created. How could I not write the bug? It’s another case of sloppiness but I don’t feel bad. I think the bug existed there before the refactoring and this is the hard part about programming: complex interactions between distant, in space and time, parts of the program. Again, more time spent reviewing the change could have prevented it. As a bonus, I managed to simplify the logic a bit. Writing software is an incremental process. I could feel bad about not writing the perfect code from the beginning but I choose to enjoy the process of finding and implementing improvements. Making the code and the program better over time. Tracking down a chm thumbnail crash Not all crashes can be fixed given information in crash report. I saw a report with crash related to creating a thumbnail crash. I couldn’t figure out why it crashes but I could add more logging to help figure out the issue if it happens again. If it doesn’t happen again, then I win. If it does happen again, I will have more context in the log to help me figure out the issue. Update: I did fix the crash. Fix crash when viewing favorites menu A user reported a crash. I was able to reproduce the crash and fix it. This is the bast case scenario: a bug report with instructions to reproduce a crash. If I can reproduce the crash when running debug build under the debugger, it’s typically very easy to figure out the problem and fix it. In this case I’ve recently implemented an improved version of StrVec (vector of strings) class. It had a compatibility bug compared to previous implementation in that StrVec::InsertAt(0) into an empty vector would crash. Arguably it’s not a correct usage but existing code used it so I’ve added support to InsertAt() at the end of vector. How could I not write the bug? I should have written a unit test (which I did in the fix). I don’t blindly advocate unit tests. Writing tests has a productivity cost but for such low-level, relatively tricky code, unit tests are good. I don’t feel too bad about it. I did write lots of tests for StrVec and arguably this particular usage of InsertAt() was borderline correct so it didn’t occur to me to test that condition. Use after free I saw a crash in crash reports, close to DeleteThumbnailForFile(). I looked at the code: if (!fs->favorites->IsEmpty()) { // only hide documents with favorites gFileHistory.MarkFileInexistent(fs->filePath, true); } else { gFileHistory.Remove(fs); DeleteDisplayState(fs); } DeleteThumbnailForFile(fs->filePath); I immediately spotted suspicious part: we call DeleteDisplayState(fs) and then might use fs->filePath. I looked at DeleteDisplayState and it does, in fact, deletes fs and all its data, including filePath. So we use freed data in a classic use after free bug. The fix was simple: make a copy of fs->filePath before calling DeleteDisplayState and use that. How could I not write the bug? Same story: be more careful when reviewing the changes, test the changes more. If I fail that, crash reporting saves my ass. The bug didn’t last more than a few days and affected only one user. I immediately fixed it and published an update. Summary of being more productive and writing bug free software If many people use your software, a crash reporting system is a must. Crashes happen and few of them are reported by users. Code reviews can catch bugs but they are also costly and reviewing your own code right after you write it is not a good time. You’re tired and biased to think your code is correct. Maybe reviewing the code a day after, with fresh eyes, would be better. I don’t know, I haven’t tried it.

yesterday 1 votes
An Analysis of Links From The White House’s “Wire” Website

A little while back I heard about the White House launching their version of a Drudge Report style website called White House Wire. According to Axios, a White House official said the site’s purpose was to serve as “a place for supporters of the president’s agenda to get the real news all in one place”. So a link blog, if you will. As a self-professed connoisseur of websites and link blogs, this got me thinking: “I wonder what kind of links they’re considering as ‘real news’ and what they’re linking to?” So I decided to do quick analysis using Quadratic, a programmable spreadsheet where you can write code and return values to a 2d interface of rows and columns. I wrote some JavaScript to: Fetch the HTML page at whitehouse.gov/wire Parse it with cheerio Select all the external links on the page Return a list of links and their headline text In a few minutes I had a quick analysis of what kind of links were on the page: This immediately sparked my curiosity to know more about the meta information around the links, like: If you grouped all the links together, which sites get linked to the most? What kind of interesting data could you pull from the headlines they’re writing, like the most frequently used words? What if you did this analysis, but with snapshots of the website over time (rather than just the current moment)? So I got to building. Quadratic today doesn’t yet have the ability for your spreadsheet to run in the background on a schedule and append data. So I had to look elsewhere for a little extra functionality. My mind went to val.town which lets you write little scripts that can 1) run on a schedule (cron), 2) store information (blobs), and 3) retrieve stored information via their API. After a quick read of their docs, I figured out how to write a little script that’ll run once a day, scrape the site, and save the resulting HTML page in their key/value storage. From there, I was back to Quadratic writing code to talk to val.town’s API and retrieve my HTML, parse it, and turn it into good, structured data. There were some things I had to do, like: Fine-tune how I select all the editorial links on the page from the source HTML (I didn’t want, for example, to include external links to the White House’s social pages which appear on every page). This required a little finessing, but I eventually got a collection of links that corresponded to what I was seeing on the page. Parse the links and pull out the top-level domains so I could group links by domain occurrence. Create charts and graphs to visualize the structured data I had created. Selfish plug: Quadratic made this all super easy, as I could program in JavaScript and use third-party tools like tldts to do the analysis, all while visualizing my output on a 2d grid in real-time which made for a super fast feedback loop! Once I got all that done, I just had to sit back and wait for the HTML snapshots to begin accumulating! It’s been about a month and a half since I started this and I have about fifty days worth of data. The results? Here’s the top 10 domains that the White House Wire links to (by occurrence), from May 8 to June 24, 2025: youtube.com (133) foxnews.com (72) thepostmillennial.com (67) foxbusiness.com (66) breitbart.com (64) x.com (63) reuters.com (51) truthsocial.com (48) nypost.com (47) dailywire.com (36) From the links, here’s a word cloud of the most commonly recurring words in the link headlines: “trump” (343) “president” (145) “us” (134) “big” (131) “bill” (127) “beautiful” (113) “trumps” (92) “one” (72) “million” (57) “house” (56) The data and these graphs are all in my spreadsheet, so I can open it up whenever I want to see the latest data and re-run my script to pull the latest from val.town. In response to the new data that comes in, the spreadsheet automatically parses it, turn it into links, and updates the graphs. Cool! If you want to check out the spreadsheet — sorry! My API key for val.town is in it (“secrets management” is on the roadmap). But I created a duplicate where I inlined the data from the API (rather than the code which dynamically pulls it) which you can check out here at your convenience. Email · Mastodon · Bluesky

2 days ago 2 votes