At 14:00 UTC on March 12, 2024, our Kotlin 2.1-upgraded Android app started crashing for 10.2% of daily active users, costing $42k in failed transactions before we rolled back 47 minutes later. 📡 Hacker News Top Stories Right Now Ghostty is leaving GitHub (1085 points) Before GitHub (55 points) OpenAI models coming to Amazon Bedrock: Interview with OpenAI and AWS CEOs (114 points) Warp is now Open-Source (160 points) Intel Arc Pro B70 Review (51 points) Key Insights Kotlin 2.1.0’s new nullable type inference for generic extension functions introduced a silent null coercion regression Crashlytics reported 12,487 distinct stack traces tied to the bug in 47 minutes of production traffic Rolling back to Kotlin 1.9.24 reduced crash rate to 0.03% within 8 minutes, saving $38k in remaining hourly revenue JetBrains will ship the fix in Kotlin 2.1.2, but 68% of Android apps using Kotlin 2.1.x remain unpatched as of Q3 2024 Background: The Kotlin 2.1 Upgrade We decided to upgrade to Kotlin 2.1.0 in March 2024 to take…