# gotchas Published articles for gotchas. This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles. ## Quiz: Python's Mutable vs Immutable Types: What's the Difference? DevFeed: [Quiz: Python's Mutable vs Immutable Types: What's the Difference?]() Original publisher: [Read original article]() Author: Real Python Published: 2026-09-16T12:00:00Z Content type: tutorial Language: en Sources: [Real Python]() Topics: [Python](), [gotchas]() Tags: [gotchas](), [python](), [test](), [tutorial]() ### AI overview An interactive 12-question quiz tests understanding of Python's mutable and immutable types, including built-in type categories and common mutability issues such as variable aliasing, mutable default arguments, and shallow copies. ### Source excerpt Find out how Python's mutable and immutable types behave, and see how mutability shapes lists, tuples, dictionaries, and your own classes. ## Designing Software for Real-World Geographic and Legal Complexity DevFeed: [Designing Software for Real-World Geographic and Legal Complexity]() Original publisher: [Read original article]() Author: Nicolas Fränkel Published: 2026-09-13T00:00:00Z Content type: opinion Language: en Sources: [Nicolas Fränkel]() Topics: [systems](), [Software]() Tags: [geography](), [gotchas](), [miscellaneous](), [software](), [switzerland](), [systems]() ### AI overview This commentary uses enclaves such as Campione d'Italia and Büsingen am Hochrhein to show why software systems must model real-world attributes independently. Country codes do not necessarily determine currency, tax, customs, mail, phone, or law, so developers should research domain-specific exceptions before designing systems. ### Source excerpt Years ago, a colleague of mine told me about two pockets of foreign land surrounded by Switzerland: Campione d'Italia and Büsingen am Hochrhein, respectively Italy and Germany. Both are enclaves of their respective country in Swiss territory: An enclave is a part of the territory of a state that is enclosed within the territory of another state. To distinguish the parts of a state entirely enclosed in a single other state, they are called true enclaves. ## Laravel Queue Gotchas Collected from Experience DevFeed: [Laravel Queue Gotchas Collected from Experience]() Original publisher: [Read original article]() Author: Freek Van der Herten (freek@spatie.be) Published: 2026-09-10T12:06:27Z Content type: tutorial Language: en Sources: [freek.dev - all blogposts]() Topics: [Laravel](), [gotchas]() Tags: [best-practices](), [gotcha](), [gotchas](), [laravel](), [practical](), [queues]() ### AI overview An article about gotchas in Laravel queues that the author says they collected through experience. ### Source excerpt Laravel queues are great out of the box, until they bite. Over the years I've collected a few gotchas the hard way. Let me save you the headache. Read more ## Linux swap Commands: Create and Manage Swap Files/Partitions DevFeed: [Linux swap Commands: Create and Manage Swap Files/Partitions]() Original publisher: [Read original article]() Author: Hayden James Published: 2026-08-26T15:13:53Z Content type: tutorial Language: en Sources: [Hayden James]() Topics: [Linux](), [btrfs](), [Kernel](), [rhel]() Tags: [blog](), [btrfs](), [commands](), [desktop](), [files](), [fstab](), [gotchas](), [guide](), [how-to](), [linux](), [partition](), [performance](), [server](), [sysadmins]() ### AI overview A practical guide to creating, activating, deactivating, and troubleshooting Linux swap files and partitions using mkswap, swapon, and swapoff. It also explains filesystem-specific considerations, including Btrfs and older XFS kernels. ### Source excerpt A practical guide to creating, managing, and tuning swap files and swap partitions on Linux using mkswap, swapon, and swapoff, with real commands and common troubleshooting fixes. Continue reading... ## How To Use Standard HTML Video & Audio Lazy-Loading on the Web Today DevFeed: [How To Use Standard HTML Video & Audio Lazy-Loading on the Web Today]() Original publisher: [Read original article]() Author: Scott Jehl Published: 2026-04-07T14:30:00Z Content type: tutorial Language: en Sources: [Squarespace](), [Squarespace Engineering Blog]() Topics: [HTML](), [lazy loading](), [web-standards](), [browsers](), [Web Development]() Tags: [audio](), [best-practices](), [browsers](), [gotchas](), [how-to](), [html](), [lazy-loading](), [video]() ### AI overview This tutorial explains how to use standard HTML video and audio lazy loading on websites. It covers recommended practices and common implementation pitfalls, noting that the feature is gaining support in major browsers. ### Source excerpt HTML video and audio lazy loading is now a web standard and quickly gaining support in all major browsers. Given Squarespace's role in proposing and implementing it, we're very excited to see how developers use it on the web. Let's cover some best practices for using video and audio lazy loading in any website, as well as some gotchas to avoid. ## EVPN IP-VRFs on Cisco IOS/XE: Configuration Notes DevFeed: [EVPN IP-VRFs on Cisco IOS/XE: Configuration Notes]() Original publisher: [Read original article]() Published: 2026-02-18T06:31:00Z Content type: tutorial Language: en Sources: [ipSpace.net blog]() Topics: [evpn](), [Cisco](), [VXLAN](), [configuration](), [BGP](), [MPLS VPN]() Tags: [bgp](), [cisco](), [configuration](), [evpn](), [gotchas](), [how-to](), [ios](), [vxlan]() ### AI overview The article shares configuration notes from getting EVPN IP-VRFs with transit VXLAN segments working on Cisco IOS/XE. It explains VLAN or bridge-domain requirements, VRF and interface setup, EVPN route-target placement, BGP activation, and related testing considerations. ### Source excerpt Last week, I described some of the gotchas I encountered while trying to make EVPN MAC-VRFs work on Cisco IOS/XE. In the meantime, I got IP-VRFs with transit VXLAN segments working. Here are the CliffsNotes: Starting with the disgusting configuration mechanism: Read more ... ## Open Source Supply Chain Security Gotchas to Avoid in 2025 DevFeed: [Open Source Supply Chain Security Gotchas to Avoid in 2025]() Original publisher: [Read original article]() Published: 2025-12-10T00:00:00Z Content type: opinion Language: en Sources: [Chainguard: Unchained]() Topics: [supply-chain-security](), [Open Source](), [Security]() Tags: [2025](), [chainguard-christmas](), [chainguard-containers](), [chainguard-libraries](), [gotchas](), [open-source](), [open-source-artifacts](), [open-source-components](), [opinion](), [security](), [supply-chain](), [supply-chain-security]() ### AI overview This commentary uses holiday gift metaphors to identify open source supply chain security pitfalls. It warns that repackaged binaries and image catalogs with questionable provenance can introduce maintenance burdens, technical debt, vulnerabilities, and malicious-code risks, and presents building directly from source as a critical control. ### Source excerpt Skip the "security gift traps." This holiday guide flags common open source supply chain gotchas and shows what to choose instead for speed and trust. ## The Dangers of Testing in SQLite as a Postgres User DevFeed: [The Dangers of Testing in SQLite as a Postgres User]() Original publisher: [Read original article]() Author: Brian Holt Published: 2025-02-17T18:46:05Z Content type: article Language: en Sources: [Blog -- Neon Docs]() Topics: [Testing](), [PostgreSQL](), [SQLite](), [SQL](), [Databases]() Tags: [floating-point](), [gotchas](), [latency](), [postgres](), [postgresql](), [sql](), [sqlite](), [testing]() ### AI overview The article explains why SQLite is convenient for isolated tests and warns that SQLite-based tests can create false confidence for PostgreSQL users. It highlights differences in SQL dialects, client-server behavior, performance, and type enforcement, including SQLite accepting a floating-point value in an INTEGER column where PostgreSQL raises an error. ### Source excerpt SQLite is genuinely an incredible piece of technology. Instead of having a list of which companies used the database, the SQLite site simply tells you its on every Android phone, every iPhone, in every browser, in every Mac, in every Windows machine. "Billions and billions of cop... ## How to add a directory to your PATH DevFeed: [How to add a directory to your PATH]() Original publisher: [Read original article]() Author: Julia Evans Published: 2025-02-13T12:27:56Z Content type: tutorial Language: en Sources: [Julia Evans]() Topics: [Shell](), [Terminal](), [Command-line interface](), [Scripting, bash](), [Zsh](), [friendly interactive shell](), [Linux]() Tags: [bash](), [config](), [files](), [flow](), [gotchas](), [history](), [how-to](), [linux](), [mac](), [syntax](), [terminal]() ### AI overview A practical guide to adding a directory to PATH. It explains how to identify whether the shell is bash, zsh, or fish, find the relevant shell configuration file, determine which directory should be added, update the configuration, restart the shell, and troubleshoot common PATH-related problems. ### Source excerpt I was talking to a friend about how to add a directory to your PATH today. It's something that feels "obvious" to me since I've been using the terminal for a long time, but when I searched for instructions for how to do it, I actually couldn't find something that explained all of the steps - a lot of them just said "add this to ~/.bashrc", but what if you're not using bash? What if your bash config is actually in a different file? And how are you supposed to figure out which directory to add anyway? So I wanted to try to write down some more complete directions and mention some of the gotchas I've run into over the years. Here's a table of contents: step 1: what shell are you using? step 2: find your shell's config file a note on bash's config file step 3: figure out which directory to add step 3.1: double check it's the right directory step 4: edit your shell config step 5: restart your shell problems: problem 1: it ran the wrong program problem 2: the program isn't being run from your shell problem 3: duplicate PATH entries making it harder to debug problem 4: losing your history after updating your PATH notes: a note on source a note on fish_add_path step 1: what shell are you using? If you're not sure what shell you're using, here's a way to find out. Run this: ps -p $$ -o pid,comm= if you're using bash, it'll print out 97295 bash if you're using zsh, it'll print out 97295 zsh if you're using fish, it'll print out an error like "In fish, please use $fish_pid" ($$ isn't valid syntax in fish, but in any case the error message tells you that you're using fish, which you probably already knew) Also bash is the default on Linux and zsh is the default on Mac OS (as of 2024). I'll only cover bash, zsh, and fish in these directions. step 2: find your shell's config file in zsh, it's probably ~/.zshrc in bash, it might be ~/.bashrc, but it's complicated, see the note in the next section in fish, it's probably ~/.config/fish/config.fish (you can run echo $__fish_config_di ## Using CSS libraries with Compose for Web - Gustavo Fão Valvassori DevFeed: [Using CSS libraries with Compose for Web - Gustavo Fão Valvassori]() Original publisher: [Read original article]() Published: 2023-12-22T00:00:00Z Content type: tutorial Language: en Sources: [Touchlab | Enterprise Mobile Innovation & Development]() Topics: [Compose](), [compose-for-web](), [CSS](), [Webpack](), [Gradle]() Tags: [cdn](), [compose](), [compose-for-web](), [compose-multiplatform](), [css](), [gotchas](), [gradle](), [kotlin-js](), [kotlin-multiplatform](), [npm](), [third-party](), [tips]() ### AI overview A tutorial on importing and using third-party CSS styles in Compose for Web. It explains three approaches: loading styles from a CDN, adding CSS files to project resources, and managing styles with NPM. It also introduces enabling CSS and SCSS support in Webpack through Gradle configuration. ### Source excerpt Using third-party styles have a few gotchas. Here are some tips and tricks to help you out. ## Kotlin and Java interoperability: Traps and gotchas DevFeed: [Kotlin and Java interoperability: Traps and gotchas]() Original publisher: [Read original article]() Published: 2023-08-21T00:15:00Z Content type: tutorial Language: en Sources: [Kt. Academy]() Topics: [interoperability](), [Java](), [Kotlin](), [gotchas](), [exceptions]() Tags: [gotchas](), [interoperability](), [java](), [kotlin](), [mockito](), [unit-test](), [workshop-learning-programming]() ### AI overview This tutorial explains surprising aspects of Kotlin and Java interoperability, including return types, function types and functional interfaces, Java keywords used in Kotlin names, Mockito's `when` function, Kotlin/JVM naming constraints, and Java checked exceptions. ### Source excerpt The parts of Kotlin and Java interoperability that might be surprising or counterintuitive. ## Performance Gotchas and Optimizations in Jetpack Compose DevFeed: [Performance Gotchas and Optimizations in Jetpack Compose]() Original publisher: [Read original article]() Author: Alex Styl Published: 2023-05-06T00:00:00Z Content type: tutorial Language: en Sources: [Composables - Concise, no-fluff video tutorials for Android developers]() Topics: [Compose](), [Jetpack Compose](), [ui](), [gotchas](), [Kotlin]() Tags: [compose](), [gotchas](), [jetpack-compose](), [kotlin-functions](), [layout](), [performance](), [ui]() ### AI overview This tutorial explains how to optimize composable functions in Jetpack Compose. It focuses on minimizing unnecessary calculations, understanding how Compose determines whether values change, reducing work in the Composition, Layout, and Draw phases, and checking performance on release builds. ### Source excerpt Performance gotchas and optimizations in Jetpack Compose ## Adding Chartkick to a Rails 6 App DevFeed: [Adding Chartkick to a Rails 6 App]() Original publisher: [Read original article]() Author: Fuzzygroup Published: 2020-04-02T00:00:00Z Content type: tutorial Language: en Sources: [Scott Johnson]() Topics: [Rails](), [App](), [Command-line interface]() Tags: [chartkick](), [command-line](), [gotchas](), [install](), [js](), [rails]() ### AI overview A tutorial on adding Chartkick to a Rails 6 application. It covers the Gemfile entry, bundle and Yarn commands, and the required application.js imports for Chartkick and chart.js. ### Source excerpt Chartkick is the charting engine that I've used for a bunch of years. When you use Chartkick on a Rails 6 app, here are some gotchas: Gemfile gem 'chartkick' Command Line bundle install yarn add chartkick chart.js yarn install --check-files Add to application.js require("chartkick") require("chart.js") ## Three.js extrude SVG path DevFeed: [Three.js extrude SVG path]() Original publisher: [Read original article]() Author: Stanko Published: 2019-12-18T00:00:00Z Content type: tutorial Language: en Sources: [Stanko Tadić]() Topics: [Three.js](), [SVG](), [3D](), [Graphics]() Tags: [3d](), [demo](), [export](), [getting-started](), [gotchas](), [graphics](), [how-to](), [svg](), [three-js]() ### AI overview A tutorial on importing SVG data into Three.js with SVGLoader and extruding SVG paths into 3D geometry with ExtrudeGeometry. It explains setup details and common issues, including the inverted Y axis when mapping SVG coordinates into Three.js. ### Source excerpt Update, September 2025 # Replaced path.toShapes(true) with SVGLoader.createShapes(path) because toShapes misses some of the SVG-specific logic implemented in the loader. Thanks to forresto who pointed it out. Also updated the demo to use a fresh version of ThreeJS. These days I'm playing with three.js again. I'm not an expert but I enjoy playing with graphics. Conveniently, a friend of mine sent me this Dribble, and I thought it would be a perfect exercise to try making it. I still haven't done it, but I did some exploration on how to built it. My plan was to draw the parallaxing layers as vectors, import it in three.js and use ExtrudeGeometry to give them a third dimension. To three.js ninjas this might be funny, but it took me some time. I haven't found well documented way, plus there are a couple of gotchas. And that is the reason I want to share this process with you. Before we start # I'll assume you have a basic understanding of three.js, and how to setup a scene. If you are just starting with it, I recommend going through their excellent Getting Started guide first. If you just want to see the end result, feel free to jump to the code or the live demo. SVGLoader # Three.js provides us with SVGLoader, but it is not the part of the main export. It is an addon, and can import it like this: import { SVGLoader } from "three/addons/loaders/SVGLoader.js"; Like it's name suggest this class loads SVG from an URL and parses it into three.js entries. If you already have SVG markup as a string, it is easy to parse it, but it is also easy to miss how to do it in the documentation. SVGLoader extends base Loader class, which contains .parse() method. That means we can do this: // Get SVG's markup const svgMarkup = document.querySelector('svg').outerHTML; const loader = new SVGLoader(); const svgData = loader.parse(svgMarkup); Now when we know how to get SVG data to three.js, let's try to extrude it. Extrude # You'll need a SVG, I used my logo: To get to the shapes we can ex ## Why Do We Write super(props)? DevFeed: [Why Do We Write super(props)?]() Original publisher: [Read original article]() Published: 2018-11-30T00:00:00Z Content type: article Language: en Sources: [Dan Abramov]() Topics: [JavaScript](), [React](), [es6](), [Code]() Tags: [gotchas](), [javascript](), [react](), [syntax]() ### AI overview This article explains why React class components call super(props), covering JavaScript constructor rules, parent-class initialization, and how React assigns props even when they are not passed to super. ### Source excerpt There's a twist at the end. ## All About Type Aliases in Kotlin DevFeed: [All About Type Aliases in Kotlin]() Original publisher: [Read original article]() Author: author@typealias.com (Dave Leeds) Published: 2018-05-14T00:00:00Z Content type: tutorial Language: en Sources: [Dave Leeds on Kotlin - typealias.com]() Topics: [Kotlin](), [Code](), [gotchas](), [import]() Tags: [code](), [function](), [gotchas](), [import](), [kotlin](), [programming](), [readability](), [type-alias]() ### AI overview A Kotlin tutorial explaining type aliases, how they make complex types easier to read and maintain, practical use cases, common gotchas, and the related Import As feature. ### Source excerpt Have you ever had a conversation like this? Hopefully you haven't had a conversation like that in real life, but you might have had one like that with your code! For example, take a gander at this: interface RestaurantPatron { fun makeReservation(restaurant: Organization<(Currency, Coupon?) -> Sustenance>) fun visit(restaurant: Organization<(Currency, Coupon?) -> Sustenance>) fun complainAbout(restaurant: Organization<(Currency, Coupon?) -> Sustenance>) } When you see a chunk of code with so many types smushed together, it's easy to get lost in the details. ## Always use button for clickable elements DevFeed: [Always use button for clickable elements]() Original publisher: [Read original article]() Author: Stanko Published: 2016-09-02T00:00:00Z Content type: tutorial Language: en Sources: [Stanko Tadić]() Topics: [browser](), [Forms](), [Chrome](), [Firefox]() Tags: [accessible](), [browser](), [browsers](), [chrome](), [forms](), [gotchas](), [screenshots]() ### AI overview A tutorial recommends using