• Stockfish MultiPV failed on one legal line, not the whole positionA production batch failed because the strict depth guard treated one shallow MultiPV line as a failed position, even when the best line reached the requested depth. The fix was to validate the result we actually use.May 2, 2026
• Stockfish backfill wedged behind a single vCPUA frozen-looking status page was actually a 9-hour Stockfish backfill on a single vCPU. The right fix was fan-out across ephemeral workers, not a fatter persistent box.Apr 30, 2026
• Savepoint test fixture masked two production bugsA clever savepoint-based test fixture made the suite 2.5x faster and silently turned green CI into evidence of nothing. Replacing it with TRUNCATE surfaced 3 real production-class bugs.Apr 25, 2026
• Datetime separator mismatch hid every same-day signalTwo ways of stringifying a Python datetime disagree on one character. That character was load-bearing in a lexicographic comparison and silently dropped 11 of 12 daily refresh runs.Mar 9, 2026