incremental-build

MSBuild rebuilds targets unnecessarily during an incremental build when custom targets declare incorrect Inputs/Outputs, use volatile output paths, or fail to register generated files via FileWrites, causing timestamp checks to fail.

To diagnose unnecessary MSBuild rebuilds, capture two binlog files and interpret the build messages to identify which targets show "Building target completely" instead of "Skipping target", revealing the specific inputs causing the out-of-date condition.

Fix custom MSBuild targets for incremental builds by declaring stable Inputs/Outputs, avoiding volatile output paths, registering generated files via FileWrites, and verifying incremental target conditions to ensure proper timestamp-based skipping.

Yes, Visual Studio Fast Up-to-Date Check (FUTDC) can differ from command-line MSBuild incremental builds, requiring environment-specific diagnosis to identify why targets re-execute in the IDE but skip correctly in command-line builds.

The best way to stop dotnet build from recompiling is to analyze the binlog for targets running instead of being skipped, then correct the incremental metadata by ensuring stable output paths and proper FileWrites registration.

You should not rely on MSBuild incremental build behavior when custom file generation targets use unstable output paths or lack proper FileWrites registration, as these prevent the build system from correctly determining if inputs have changed.