how-to

Why the output of an MSBuild Exec task disappears from dotnet build and dotnet restore since .NET 9, why StandardOutputImportance="High" does not bring it back, and the fixes that do: -tlp:verbosity=detailed, Directory.Build.rsp, -tl:off, and promoting lines to warnings. Checked on SDK 10.0.302 and 11.0.100 RC3.

Put [MemberNotNullWhen(true, nameof(X), nameof(Y))] on the HasValue property itself, naming the members that become non-null. It works for nullable value types and reference types, but the compiler barely checks the getter, ignores base-class members, and never notices when the state changes afterwards. Verified on .NET 10 SDK 10.0.302 and .NET 11 RC3.

Anything you compile into a Flutter web build, including --dart-define values, ships to the browser in plain text. The only safe pattern is a small backend proxy that holds the key, authenticates the user, pins the model, and streams the Responses API SSE back. Full Dart shelf proxy and Flutter client, tested with Flutter 3.44, Dart 3.12, and http 1.6.

Lock one Flutter route to landscape or portrait with SystemChrome.setPreferredOrientations without breaking the rest of the app: a stack-based lock that survives pushReplacement and restores on pop, why the empty list is the wrong reset, why iPad multitasking and Android 16 large screens ignore the lock, and what UIRequiresFullScreen means after iPadOS 26 and the iOS 27 SDK. Tested on Flutter 3.47.8 with Dart 3.13.7 and Xcode 27.1.

Model followers and following on a single User entity in EF Core 11: what the convention builds, why SQL Server quietly turns one join foreign key into ClientCascade, how to map an explicit Follow join entity with a timestamp, and how to delete a user without error 547 or 1785.

Microsoft.AspNetCore.OpenApi only marks a response nullable when the action returns a bare T? (and, on .NET 10, not even Task<T?>). ActionResult<T?> and IActionResult lose the annotation on both .NET 10 and .NET 11 RC2. Here is why, a tested operation transformer that fixes it, and the 204 No Content trap that makes the spec lie unless you also change MVC's formatter.

Subclass ThemeExtension, register one instance per ThemeData through the extensions list, read it with Theme.of(context).extension<T>(), and write a real lerp so MaterialApp's AnimatedTheme interpolates your tokens during a light/dark switch. Covers colors, radii, shadows, text styles and booleans, the missing-extension crash, the copyWith trap that drops every other extension, and why you need == and hashCode, all verified with widget tests on Flutter 3.44.8.

AnimatedSwitcher only transitions when Widget.canUpdate says the new child is a different widget, so Text to Text with no key just updates in place. Here is the one-line fix, where the key has to sit, why UniqueKey is a trap, the slide-direction bug caused by a static transitionBuilder, and the layout jump from the default Stack, all verified with widget tests on Flutter 3.44.8.

Android kills backgrounded Flutter apps to reclaim memory, and when the user comes back every StatefulWidget starts from scratch. Here is how to opt in with restorationScopeId, RestorationMixin and Restorable properties, restore text fields, scroll offsets and pushed routes, write a custom RestorableValue, and test it all with restartAndRestore and adb, verified on Flutter 3.44.8 and an Android 16 emulator.

FlutterError.onError only sees errors thrown inside framework callbacks. Unawaited futures, timers, streams, and code after an await go somewhere else. Here is which handler catches which error, measured on Flutter 3.44.8, and the main() setup that catches all of them, including on web.