标签：#c

This is a submission for DEV's Summer Bug Smash: Clear the Lineup , powered by Sentry . Project Overview I built LeakLens Control Room to keep AI away from the financial math. Python calculates every dollar. The optional model explains the evidence. A human decides whether to act. LeakLens is a live, functional restaurant margin-review application built with Python, SQLite, HTML, CSS, and JavaScript. It uses synthetic data in the public demo. The optional application narrative provider defaults to GPT-5.6, but every rate, threshold, ranking, and dollar scenario comes from deterministic code. Then a date string proved that deterministic code can still lie. I had let a raw CSV field decide which operating day counted as "current." Bug Fix or Performance Improvement The symptom LeakLens groups channel metrics by date, sorts those dates, and analyzes the last one against prior days. That works when every input is canonical ISO data such as 2026-07-09 . The loader only checked that the date field was not blank. This input slipped through: metrics = [ DailyMetric ( " 2026-7-9 " , " direct " , 500 , 250 , 0 , 0 , 125 ), DailyMetric ( " 2026-07-10 " , " direct " , 1000 , 50 , 0 , 0 , 250 ), ] July 10 is later than July 9. Python's string ordering sees something else: sorted ([ " 2026-07-10 " , " 2026-7-9 " ]) # ['2026-07-10', '2026-7-9'] LeakLens selected the final string, 2026-7-9 , as the current day. That mistake spread through the report: expected current date: 2026-07-10 actual current date: 2026-7-9 actual gross sales: 500.00 sales-loss scenario: 500.00 discount scenario: 225.00 The input had not shown a current sales collapse or discount leak. The analyzer compared the days backward and produced $725 of false scenario impact from synthetic data. For a restaurant operator, this is worse than a visible crash. A crash asks for attention. A plausible financial report can send someone to audit the wrong promotion, question the wrong manager, or change a schedule that was

TL;DR: Passing a historical blockNumber to eth_call , eth_getBalance or eth_getLogs silently routes your request to the archive tier of hosted RPC providers. In our production metrics, archive calls cost on average 26.7x more compute units than the same call at latest . This post explains why, shows the exact client code pattern that triggers it, and gives you three Prometheus queries to measure your own archive exposure in under a minute. Full cross provider measurements are published in the OpenChainBench RPC benchmarks . Last week our RPC cost dashboard flagged an overage projection above four thousand dollars for a single billing cycle on a single provider. On paper, our services were doing normal eth_call operations. In practice, one small pattern buried in three separate indexers had multiplied our compute unit consumption by more than an order of magnitude, and nothing in the code review process had surfaced it. This post breaks down what an archive multiplier is, why it silently inflates blockchain RPC bills across every major hosted provider, and how to detect it in your own Prometheus stack before the next overage alert lands in Slack. What does "archive" mean at the Ethereum node level? Every request that reads the state of a smart contract, whether through eth_call , eth_getBalance , eth_getStorageAt , eth_getCode , or a batch of these, requires the RPC node to reconstruct the world state at a specific block height. Ethereum clients handle this in two modes. Full node mode. The state trie is kept in memory or on fast SSD for the tip of the chain plus a rolling window of recent blocks. On Geth default settings that window is 128 blocks deep. Any query targeting latest , pending , or a block within that window resolves in a few milliseconds against the current state. Archive node mode. The client preserves every intermediate state trie since genesis. Answering a query at a block from months or years ago requires reading historical trie data off disk and re

TypeScript Generic Constraints in Depth: extends , keyof , and the Patterns That Prevent Runtime Errors This article was written with the assistance of AI, under human supervision and review. Most TypeScript runtime errors stem from unconstrained generics that accept anything and crash on nothing. Teams write function get<T>(obj: T, key: string) and ship code that compiles cleanly but throws Cannot read property 'undefined' of undefined in production. The compiler stays silent because the generic accepts any type and the key accepts any string—no constraint exists to prove the key belongs to the object. Generic constraints solve this by restricting what types a generic parameter can accept. The extends keyword establishes a boundary—the generic must satisfy a specific shape. The keyof operator extracts valid keys from that shape. Together they form a type-level contract that makes illegal property access unrepresentable. The corrected signature function get<T, K extends keyof T>(obj: T, key: K): T[K] proves at compile time that key exists on obj , eliminating the entire class of property-access errors. This distinction is critical. Unconstrained generics provide no safety beyond what any offers. Constrained generics encode domain rules directly into the type system, shifting entire categories of bugs left from runtime to compile time. The patterns that follow demonstrate how production codebases use extends and keyof to build type-safe APIs that fail fast during development instead of silently in production. Key Takeaways Generic constraints with extends restrict type parameters to specific shapes, preventing the compiler from accepting types that would cause runtime failures. The keyof operator extracts object keys as a union type, enabling type-safe property access when combined with extends keyof constraints. Combining T extends SomeType with K extends keyof T creates a compile-time proof that a key exists on an object, eliminating property-access errors. Conditi

Try asking this in your next team meeting: "Who on our team is the best at using AI?" There will probably be a moment of silence. Someone thinks of the person who uses the tools the most. Someone thinks of the person who's good with prompts. Someone thinks of whoever recently produced something impressive-looking with AI. But none of these answers feels convincing. There's a gut sense that something is off — and yet nobody knows what the right criterion would be. Nearly every company is standing in front of this wall right now. AI competence is rising to the top of hiring and performance criteria, and there's no yardstick to measure it with. This essay proposes one. The short answer is a set of five axes I call ABCD2. But before that, we need to fix the question itself. The very idea of "good at using AI" is wrong The title of this essay says "good at AI" — but that phrasing is itself the trap. The word "using" carries a hidden frame: AI is a tool, and the person is a user. It puts AI on the same shelf as Excel and Photoshop — something you get skilled at operating. On top of that frame, evaluation naturally becomes a measure of tool proficiency. How many features do you know? How fluently do you operate it? But AI is not a hammer. AI is an engine that judges and executes. It's less like a tool and more like a junior colleague you can delegate work to. And once you think of a junior colleague, the frame flips. Behind every junior who performs well, there is invariably a senior who makes them perform well — someone who explains the context of the work, lays out the criteria for judgment, makes it safe to ask about ambiguities, and verifies the output. That senior isn't "using" the junior. They are making the junior do the work well . AI is exactly the same. The person who truly gets the most out of AI is not the person who is good at using AI, but the person who helps AI do the work well. And what do they help with? Two things, broadly. One is knowledge building — pr

**🙄 فى كتاب chapter الصدمة دي هي بالظبط اللي حسيت بيها وأنا بقرأ أول “operating system: three easy Pieces “ ‘OSTEP’. 🖤اهلا بيكم ! يارب تكونوا بخير 💯 حابه اشارك معاكم رحلتى مع قراءة الكتاب ونستفيد منه سوا قبل ما نعرف هو !!!! ولا لا OS is virtual machine 🤔 !!!!دا يعنى ايه ووظيفته ايه OS تعالوا الاول نعرف ال موجودة فى الكمبيوتر ولا لا ؟؟؟؟ RAM وال CPUزى ال HARDWARE وهل هو قطعة ::هنبدأ من الاخر موجود على الكمبيوتر SW هو عبارة عن HW يسيدى مش قطعة OSال .على الجهازINSTALL ولازم يبقى ووظيفته ايه؟؟؟ OS طب يعنى ايه ‘OS’ اختصار “OPERATING SYSTEM”. .“يعنى نظام تشغيل “ .👁‍🗨👁‍🗨 تعالوا نعرف معنى ” نظام تشغيل” ونفسرها نظام تشغيل يعنى مسئول عن 1_ “HWالنظام “من غيره مش هيبقى فيه نظام خصوصا لقطع ال . يعنى بناخد منه الاذن للعمليات HW ببعضه وكمان بيدير ال HWيعنى هو بيربط ال 👏 . (Order)من الاخر بيخلق “النظام” 2_.”التشغيل “هو المسئول عن تشغيل البرامج Learn about Medium’s values هو اللي بيتحكم في دورة حياة البرنامج بالكامل؛هو اللي بيبدأ تشغيله في الذاكرة،OSيعني الـ وبيحدد هو محتاج إيه من إمكانيات الجهاز عشان يشتغل بكفاءة وبيفضل مراقبه ويحميه طول ما هوشغال ، ولحد ما تقفليه بنفسك 🌹 .ويقوم هو بتنظيف الذاكرة وتوفير المساحة لغيره 🧐::وظيفته بقا بيخلي البرنامج يشتغل بسهولة:1️⃣ لأنه بيخلق للبرنامج بيئة وهمية مريحة، وبيخفي عنه كل التعقيدات والأسلاك بتاعة الهاردوير عشان يشتغل بسلاسة 2️⃣: بيسمح للبرامج إنها تشارك الذاكرة بين كل البرامج بالعدل RAM بيشتغل كعسكري مرور بيوزع مساحة الـ . وبيحمي كل برنامج في مساحته الخاصة 3️⃣: بيمكن البرامج إنها تتعامل مع الأجهزة بيعمل كـ “وسيط” أو مترجم بيوصل كود البرنامج بالقطع الحقيقية (زي الشاشة أو الهارد) .عشان ينفذ أوامره فوراً بيعمل التلات حاجات دول إزاي في نفس الوقت وبمنتهى السلاسة؟ ؟؟؟OS طب الـ بيعملهم يسيدى عن طريق أكبر خدعة سحرية في عالم الكمبيوتروهي الـ Virtualization👌 كنت حابة جداً أكلمكم المرة دي عن خدعة الـ “Virtualization” 💎 😌👁👁اللي اتكلمنا عليها في العنوان، بس لقيت البوست هيبقى طويل أوي عليكم ✔🔥!!وعشان متعبكمش معايا.. هنخليها للبوست الجاي إن شاء الله 💯✅!!بيعمل الخدعة دي إزاي OSاستنوا البوست الجاى عشان نعرف الـ 💋.دمتم بخير **

In 2017, I bought an old Magnus chord organ off Craigslist for $10. It's one of my favorite music gear purchases. Electric chord organs let you play full chords with just a press of a button, making them perfect for aspiring singer-songwriters or fooling around at home. But chord organs largely fell out of favor […]

Birdfy has kicked off a midyear sale, taking up to 40 percent off a range of its smart bird feeders. One of the best deals is on Netvue’s Birdfy Feeder AI-Powered Smart Bird Feeder with Camera, which has dropped to $149.99 at Birdfy and is its second-best price to date. The bundle, which includes a […]

"Everybody knows the Greeks are inside."

I might be the only SRE on Earth with his own bowling center. It's a more in-depth gig than you'd think. My family and I bought an abandoned 8-lane bowling center in the rural mid-west. In our small town there weren't many recreation options for families. You've heard of a food desert? This is an R&R desert. It had been abandoned for a good reason. The roof leaks, the electrical system was constantly surging, and my 70-year-old bowling equipment (still) doesn't work perfectly. The system that ke

Harness local AI for notes Discussion | Link

Prevent product drift in AI-written code Discussion | Link

The manosphere influencers Andrew and Tristan Tate were arrested Saturday in Miami by US Marshals in relation to new rape and sex trafficking charges in England. According to the Associated Press, British authorities are seeking the brothers' extradition. The new charges facing Andrew Tate include seven counts of rape, three of sex trafficking, three counts […]