Daily notes on .NET, C#, EF Core, MAUI, Blazor, and Flutter - for developers who ship.

Genkit Dart 1.0.0 freezes the API, moves HTTP serving into core with GenkitRouter, and changes the streamed error frame. Shipped Flutter apps on a 0.17 client need sendLegacyErrorFrame.

Balancing groups (?<name>) and (?<-name>) turn a .NET regex capture group into a stack, so one pattern can match arbitrarily nested parentheses or <div> tags. The full pattern, how the stack works, inner-content capture with (?<inner-open>), and the gotchas verified on .NET 11 RC1: the empty-stack check, catastrophic backtracking, NonBacktracking, and mixed bracket types.

A compiled model is generated C# that recreates your EF Core model without running OnModelCreating. Measured on EF Core 11 RC1: model load drops from 714 ms to 215 ms at 500 entities, but the MSBuild route (which replaced EFOptimizeContext) is slower, stale models fail silently, and query filters block generation.

A build mode (debug, profile, release) decides how Flutter compiles your Dart code. A flavor (dev, staging, prod) is a native build variant you define in Gradle and Xcode that decides which app you ship. They are independent axes: 2 flavors times 3 modes is 6 builds. Verified on Flutter 3.44.8 with AGP 9.0.1, source checked against 3.47.7.

Magentic orchestration is Agent Framework's port of AutoGen's Magentic-One: an LLM manager writes a fact sheet and plan (the task ledger), then grades every round with a JSON progress ledger to pick the next agent, detect stalls and replan. Here is how the loop works on Microsoft.Agents.AI.Workflows 1.24.0 and agent-framework-orchestrations 1.3.1, what it costs per round, and the limit defaults that let it run forever.

A transparent struct is one the ABI treats exactly like its only field. .NET 11 has no such guarantee: a struct wrapping a double is passed in RCX on Windows x64 but in XMM0 on Linux and macOS. Here is the disassembly from the .NET 11 JIT on three ABIs, the P/Invoke bugs it causes, and how to write wrapper types that are safe at every boundary.

Flutter 3.44 made Swift Package Manager the default for iOS and macOS, but an existing app keeps CocoaPods until you remove it. How to check which plugins are SwiftPM-ready, let the tool migrate the Xcode project, delete the Podfile safely, handle pods-only plugins and custom Podfile logic, and roll back if you need to.

Semantic Kernel .NET 1.81.0 fixes a FileIOPlugin oracle: WriteAsync told the model a file outside AllowedFolders existed, was read-only, and where it lived. Measured before and after.

A shadow property is a column EF Core tracks without a matching CLR property. Here is why EF Core 11 creates them (missing FK properties, misnamed FKs, type mismatches, split relationships), how to spot the BlogId1 kind in a migration, how to fix each cause, and how to use shadow properties on purpose.

The GitHub Copilot SDK (1.0.18, October 8, 2026) is a thin client for the Copilot CLI runtime: your app speaks JSON-RPC to the same agent loop that powers Copilot CLI, with built-in file and shell tools, MCP, sub-agents, hooks, and BYOK. How it is wired, four things you can build with it, and the defaults that will bite you in production.