Production Bugs

Swift 6 strict concurrency: How to safely use @_silgen_name bindings to private C frameworks with callback-based APIs?

by

Summary Swift 6 strict concurrency requires careful handling of callback-based C APIs, especially when integrating with private frameworks like MultitouchSupport. The challenge arises from uncontrolled thread execution in callbacks, leading to potential data races and concurrency violations. This postmortem explores the root cause, real-world impact, and solutions for bridging such APIs with Swift’s structured concurrency. … Read more

How to change the VSCode SmartSelect interaction with quotation marks

by

Summary The recent behavior change in VSCode’s SmartSelect now includes quotation marks when expanding selections using editor.action.smartSelect.expand. This affects users relying on precise selection behavior, particularly those using keyboard shortcuts or extensions that depend on the previous exclusion of quotation marks. Root Cause The root cause is a change in VSCode’s selection algorithm, likely introduced … Read more

Google Cloud Eventarc trigger not firing for Firestore (2nd Gen Cloud Function) in nam5

by

Summary A 2nd Gen Cloud Function deployed in us-central1 never fired because the Firestore-triggered Eventarc event was configured in nam5, a multi‑region Firestore location that does not interoperate with Eventarc triggers in single‑region Cloud Function locations. Eventarc requires co‑located trigger region, database region, and destination region for Firestore-native events. Root Cause The failure occurred because … Read more

Infinite AI Feedback Loop

by

Summary An infinite AI feedback loop occurs when AI systems generate content based on data derived from their own previous outputs, leading to amplification of errors and loss of diversity in training data. This loop can degrade model performance over time, as the AI increasingly relies on its own flawed or biased outputs. Root Cause … Read more

How can I detect a cursor-up-event in QLineEdit PyQt5

by

Summary Issue: In a PyQt5 GUI project, detecting cursor-up/down events in a QLineEdit widget to enable scrolling through previously stored parameter texts was not straightforward due to the lack of direct callbacks or actions for these events. Root Cause PyQt5’s QLineEdit does not provide built-in signals or methods to directly detect cursor-up/down key presses. The … Read more

How to print statement size pdf in java

by

Summary Printing an 8.5×5.5 PDF silently using PDFBox 3.0.6 in Java resulted in sideways output. The root cause was incorrect page rotation handling in the printing logic. Root Cause PDFBox’s default printing behavior does not account for non-standard page sizes. The PrintService implementation lacked explicit orientation control, relying on system defaults. Page rotation metadata in … Read more

When you open the shop UI after clicking yes, it doesn’t allow you to buy the item fries or close the UI with the close button

by

Summary The issue occurs when opening the shop UI after clicking “yes,” preventing users from purchasing “fries” or closing the UI with the close button. This is due to missing event handling for UI interactions and incorrect state management in the WorkerDialogSystem. Root Cause Missing Event Listeners: The UI elements (buy button, close button) lack … Read more

Can MutableSharedFlow Emit Nothing

by

Summary This incident examines a subtle but common misuse of MutableSharedFlow in Android/Kotlin applications: using a Boolean emission solely as a navigation trigger. The underlying issue is the assumption that a SharedFlow can “emit nothing,” when in reality it always emits a value, even if that value is meaningless. This postmortem explains why this pattern … Read more

How to troubleshoot Dart Analysis Server not responding on VSC?

by

Summary The Dart Analysis Server became unresponsive in Visual Studio Code (VSC), causing issues like “Format on save” hanging indefinitely and variable type identification failing on mouse hover. The problem persisted despite restarting the analysis server, VSC, and the machine. Root Cause The root cause was a deadlock in the Dart Analysis Server, triggered by … Read more

Programming language

by

Summary This postmortem analyzes how PHP internally handles form data, why insecure handling leads to SQL injection, XSS, and other vulnerabilities, and how senior engineers design robust validation and sanitization pipelines. The incident pattern is common: developers trust $_POST and $_GET too early, skip validation, and directly embed user input into output or queries. Root … Read more