Summary STM32Duino core produces double CRLF (\r\n\r\n) for string constants in Serial.println() while numeric values output correctly. SAMD51 core behaves as expected with single CRLF (\r\n) for both cases. Root cause stems from HAL-level CRLF conversion conflicting with Arduino’s standard newline handling. Root Cause STM32 HAL UART drivers automatically convert \n to \r\n during transmission. … Read more
Summary A custom TemplatedControl in Avalonia failed to render visual error states (specifically the red border) despite correctly capturing and propagating validation errors. While the error text was visible via the DataValidationErrors container in the template, the inner TextBox lacked the necessary pseudoclass state to trigger the theme’s error styling. This resulted in a broken … Read more
Summary The arrow in a PlantUML sequence diagram fails to attach to the activate bar when a self‑call is followed by an activate statement. This leads to a misleading visual that suggests the call returns to the wrong scope. The root issue is a misunderstanding of how activation bars are rendered when nested self‑activations occur. … Read more
Summary This postmortem examines a common database connection management challenge in Delphi/FireDac applications transitioning from SQL Server (with MARS) to PostgreSQL compatibility. The core issue involves multiple concurrent result sets on a single database connection, where the default FireDac behavior conflicts with RAD development patterns that encourage declarative component configuration. The problem manifests when developers … Read more
Summary Spring Data JDBC does not automatically map composite ID components to their own table columns. When a composite key record (ServiceId) is used as the @Id, Spring Data JDBC expects the table to have a single column named after the ID property (or a custom column mapping). It does not introspect the composite record’s … Read more
Summary A production issue was identified in an iOS Progressive Web App (PWA) where a white gap appeared at the bottom of the screen, below the bottom navigation bar. Despite using viewport-fit=cover and 100dvh, the layout failed to extend into the safe area inset (the home indicator zone). This resulted in a broken user experience … Read more
Summary The Utf8JsonWriter you create with new(File.Create(…)) owns the underlying `FileStream, and disposing the writer does not close that stream. The file remains locked, so the subsequent File.OpenRead fails with “the process cannot access the file … because it is being used by another process.” The fix is to also dispose the FileStream (or use … Read more
Summary A production system experienced cache fragmentation and reduced hit rates due to non-deterministic URL generation. The issue stemmed from a legacy Perl CGI implementation using query_form to construct query strings. Because Perl hashes are unordered collections, the resulting URL parameters were being generated in a different sequence for identical functional requests. This caused HTTP … Read more
Summary A production application experienced silent data loss and partial reads on a serial port following a major dependency upgrade from Boost 1.64 to 1.84. The failure was specifically linked to the interaction between the Asio reactor (epoll) and the existing file descriptors within a complex event loop. The issue was masked in isolated test … Read more
Summary A documentation workflow bottleneck was identified where engineers required a way to embed ASCII diagrams directly within reStructuredText (RST) files that would automatically render into high-quality graphical assets during the Sphinx build process. The goal was to avoid the overhead of external image files while maintaining the “documentation as code” principle, similar to how … Read more