UICollectionViewCell behavior on different iPhone simulators (iPhone 16/iPhone 16 Pro Max)

Summary This postmortem analyzes a subtle but real-world UIKit rendering issue: a UICollectionViewCell that displays correctly on one simulator (iPhone 16) but fails to show its glow highlight on another (iPhone 16 Pro Max) until the user interacts with the carousel. The behavior stems from layout timing, shadow-path initialization, and scroll-position–dependent selection logic. Root Cause … Read more

Apache NIFI – Fail to insert using PutDatabaseRecord: Record does not have a value for the Required column ‘name

Summary A PutDatabaseRecord failure in Apache NiFi occurred because incoming CSV records did not map correctly to the required PostgreSQL column name, causing NiFi to reject the insert with: “Record does not have a value for the Required column ‘name’.” Root Cause The failure was triggered by a mismatch between the CSV structure and the … Read more

Issues with the new Whatsapp update/

Summary A recent WhatsApp Desktop update introduced a regression where the application no longer registers itself as a share target in Windows Explorer. As a result, WhatsApp Desktop disappears from the Windows “Share” menu, preventing users from sending files directly from File Explorer. Root Cause The underlying issue stems from WhatsApp Desktop failing to correctly … Read more

asynchronously download http webpages in tcl

Summary The problem at hand is to asynchronously download HTTP webpages in TCL. The provided code attempts to fetch multiple webpages using the http::geturl command, but it lacks proper synchronization and handling of asynchronous requests. Root Cause The root cause of the issue is the lack of proper handling of asynchronous requests. The http::geturl command … Read more

How to fix ‘incomplete type’ error in a circular dependency?

Summary The ‘incomplete type’ error in C++ arises from circular dependencies between classes or templates. In the given scenario, T::U depends on M::I, which in turn depends on M::V, derived from T::U, creating a cycle. This prevents the compiler from fully defining types, leading to errors. Root Cause Circular Dependency: T::U relies on M::I, which … Read more

Web Application Budget

Summary Developing a budget for a complex web application like the one described requires a structured approach to ensure fair compensation for the effort involved. The scope includes multiple components such as AI integration, payment portals, and admin panels, which demand specialized skills and significant time investment. A detailed breakdown of tasks, resource allocation, and … Read more

Time complexity analysis for a leetcode question

Summary Time complexity analysis for the LeetCode “Longest Common Prefix” problem revealed a misunderstanding in evaluating the efficiency of the submitted solution. The solution used startsWith and slice operations, both of which are O(N) in the worst case. However, LeetCode reported the solution as O(N), which initially seemed incorrect. Upon deeper analysis, the overall complexity … Read more

After set body display: flex;justify-content: center;align-items: center;, the page is cuted off some on the top. Why?

Summary The issue occurs when applying display: flex; with justify-content: center; and align-items: center; to the <body> element, causing the page content to be vertically and horizontally centered, but also introducing unexpected vertical whitespace at the top. This results in the page appearing “cut off” on larger screens. Root Cause Flexbox on <body>: The <body> … Read more

How to parse informal Persian number words into an integer currency value (Rial)

Summary A production incident occurred in a Persian‑language financial application where informal Persian number words were parsed incorrectly, producing wrong integer Rial values. The failure stemmed from ambiguous colloquial forms, mixed units (تومان/ریال), and inconsistent tokenization rules. The system behaved unpredictably when users combined spoken‑style numerals, misspellings, and magnitude units in the same sentence. Root … Read more

HTML Canvas Drawing Works on Desktop But Not Mobile

Summary A signature‑capture canvas worked flawlessly on desktop but failed to register touch drawing on mobile Safari. The canvas rendered correctly, but touch events never produced usable coordinates, resulting in no visible strokes. Root Cause The underlying issue was incorrect handling of touch events on iOS Safari, specifically: Using touches instead of changedTouches during touchend … Read more