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"title": "Unit 20 \u00b7 Language valence: Kotlin under policy \u00b7 q27b",
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"content": "Hardcore project: one cross-platform app \u2014 async APIs with unpredictable runtimes that must all make sense at the UI layer, a 3D viewport, server modules, end-user plugin support, several data stores, desktop and mobile. Company policy: it ships 100% in Kotlin. Gut reaction first, then your top 3 technical risks. Keep it tight."
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"content": "**Gut Reaction:**\nThis is a recipe for a maintenance nightmare. Kotlin is fantastic for backend and Android, but forcing it as the *sole* language for a high-performance 3D viewport and cross-platform UI (especially iOS) ignores the ecosystem realities. You\u2019re fighting the grain on every layer.\n\n**Top 3 Technical Risks:**\n\n1. **iOS UI & 3D Performance Bottleneck:**\n Kotlin/Native on iOS lacks mature, high-performance UI frameworks (Compose Multiplatform is still maturing for complex 3D integration). You\u2019ll likely end up with a heavy JNI/FFI bridge to native iOS views or a suboptimal Compose renderer, leading to janky 60fps+ 3D rendering and poor native feel. *Risk: Unacceptable UX on half your target platforms.*\n\n2. **Plugin System Complexity & Security:**\n End-user plugins in a single-language, cross-platform app require a robust sandboxing and reflection/serialization layer. Kotlin\u2019s plugin ecosystem (e.g., KSP, custom classloaders)"
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"content": "Update: CI moves to cheap Linux containers, plugins must be scriptable by end users, and the 3D viewport must hit 120 fps on mid-range Android. Re-plan in Kotlin: what breaks first, and what exactly do you do about it?"
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"content": "**Gut Reaction:**\nYou are now asking for a Ferrari engine in a go-kart chassis. 120 FPS on mid-range Android with a Kotlin-only stack, async chaos, and user scripts is not just hard; it\u2019s actively hostile to the JVM/Kotlin/Native runtime characteristics. The \"cheap Linux CI\" constraint is the least of your worries\u2014it\u2019s just a cost optimization. The real killer is the physics of the runtime.\n\n**What Breaks First:**\n**The Main Thread & GC Pauses.**\nMid-range Android devices have limited CPU headroom and aggressive thermal throttling. Kotlin runs on the JVM (Android) or Native (iOS/Desktop).\n- **JVM GC:** Even with ZGC/Shenandoah (not fully supported/optimized on Android), stop-the-world pauses will cause frame drops. 120 FPS = ~8.3ms per frame. A 2ms GC pause is a 24% frame budget loss.\n- **Kotlin/Native Memory Management:** Reference counting has overhead. Frequent allocation/de"
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