composition-root-guard

Create the BLL with a single internal constructor receiving dependencies as interfaces, declare an internal contract in ContratosInternosBLL.cs if other BLLs depend on it, then construct it once in CompositionRoot.Inicializar() after its dependencies and expose a static getter.

Composition Root is the single location where the entire object graph is constructed, triggered once at application startup. Each class receives dependencies via constructor injection, guaranteeing one shared instance per service and explicit, compiler-checked dependencies.

Service Locator hides dependencies inside method bodies, making them invisible to the compiler and enabling duplicate object graph construction. Constructor injection makes dependencies explicit and lets the compiler prevent construction outside the root via internal constructors.

Wire a PowerShell verification script into Directory.Build.targets with a custom MSBuild target gated by a property flag. The script scans source files for forbidden patterns like new BLL calls outside the root and fails the build on violations.

Yes, internal constructors allow injecting test doubles from a test project by adding [assembly: InternalsVisibleTo("<Tests>")] to the BLL AssemblyInfo. This is the intended testing path, avoiding the need for public default constructors.

Functional startup steps like integrity checks or language loading belong in a separate initializer BLL, not CompositionRoot.Inicializar(). The root only composes objects without business side effects, since it is also triggered from the exception handler.