# Postmortem: Failed Data Insertion in PHP/MySQL Form Handler ## Summary Form submissions weren’t persisting in MySQL despite valid database connections and table structure verification. The key failure was inadequate error handling masking underlying SQL processing failures, compounded by SQL injection vulnerabilities. ## Root Cause – **Absence of runtime error reporting** silenced critical MySQL constraint … Read more
## Summary Self-invocation occurs when a method within a Spring bean calls another `@Transactional` method in the same bean. Despite using CGLIB proxies for transaction interception, the transactional behavior fails because the call bypasses the proxy layer, executing directly on the target instance. ## Root Cause – Spring’s proxy-based AOP creates wrappers around beans to … Read more
# Google Maps Marker & Bubble Misaligned on Android: A Production Postmortem ## Summary – Custom marker bubbles appeared misaligned on Android while working correctly on iOS – Bubble positioning was being calculated synchronously after marker creation – Android required additional time for marker layout completion before reliable coordinate fetching – Debugging revealed `getScreenCoordinate()` returned … Read more
# Postmortem: Decimal Input Overflow in Calculator Application ## Summary A calculator application allowed users to input unlimited decimal digits via button presses despite UI-level safeguards. The attempted solution prevented duplicate decimal points but failed to enforce single-digit precision after the decimal separator in numeric inputs. ## Root Cause 1. Validation scope was incomplete: – … Read more
# Postmortem: Snowflake `COUNT_IF` Behavior vs. Documentation Discrepancy ## Summary – Snowflake’s `COUNT_IF` function returns `0` when no records meet the condition. – Official documentation claims it should return `NULL` in such cases. – Discrepancy confirmed via live testing of `COUNT_IF(1 != 1)` returning `0`. ## Root Cause – Implementation aligns with SQL’s `COUNT` aggregation … Read more
# Postmortem: Silent Failure in Google Sheets Macro Due to Missing Write Operation ## Summary A Google Sheets macro was created to add a value from cell B21 to cell B4. Despite correct value calculation, the updated result wasn’t saved because the script lacked a write operation to persist changes to the spreadsheet. ## Root … Read more
# Production Postmortem: Older Project Fails to Build Universal Binary for Apple Silicon ## Summary An Objective-C project migrated to Apple Silicon revealed compatibility issues: – Could only run under Rosetta emulation – Build system refused to target Apple Silicon (`arm64`) – Identified problematic third-party libraries (`libssl.a` and Crashlytics) – Build configuration showed `ARCHS_STANDARD` as … Read more
# Can the Duan et al. 2025 “breaking the sorting barrier” faster-than-Dijkstra SSSP algorithm speed up Yamada–Kinoshita negative-cycle enumeration? ## Summary This postmortem explores whether Duan et al.’s advanced single-source shortest path (SSSP) algorithm for nonnegative weights can accelerate Yamada–Kinoshita’s method for enumerating negative cycles. Key conclusions: – Duan et al.’s algorithm cannot be directly … Read more
# Technical Postmortem: Book Ordering System Failure Due to Tight GUI-Coupling ## Summary A Python-based book ordering system implemented with Tkinter failed core separation requirements. The solution tightly coupled business logic with UI code, resulting in: – Invalid operation prevention failures – Validation logic duplication – Untestable core functionality – Rigid architecture resistant to change … Read more
# Autocomplete Error: USA Country Filter Returns Mexican Cities ## Summary – When users selected “United States” in a country-autocomplete field, the dependent city-autocomplete field incorrectly displayed Mexican cities – The app used Google Maps Legacy Place Autocomplete with country restriction parameters (`AutocompleteFilter`) – All tested countries (UK, France, Spain, Russia) worked correctly – error … Read more