Enhance bodi exceptions to include name of interface when duplicate registrations attempted

CHANGELOG.md

@@ -2,9 +2,11 @@
 
 ## Improvements:
 
+* Enhance BoDi error handling to provide the name of the interface being registered when that interface has already been resolved (#324)
+
 ## Bug fixes:
 
-*Contributors of this release (in alphabetical order):* @obligaron
+*Contributors of this release (in alphabetical order):* @clrudolphi, @obligaron
 
 # v2.2.1 - 2024-11-08
 

Reqnroll/BoDi/ObjectContainer.cs

@@ -364,7 +364,7 @@ public IStrategyRegistration RegisterTypeAs<TType, TInterface>(string name = nul
     public IStrategyRegistration RegisterTypeAs(Type implementationType, Type interfaceType, string name = null)
     {
         if (!IsValidTypeMapping(implementationType, interfaceType))
-            throw new InvalidOperationException("type mapping is not valid");
+            throw new InvalidOperationException($"The type mapping is not valid. The {implementationType} is not assignable to the interface {interfaceType}");
         return RegisterTypeAsInternal(implementationType, interfaceType, name);
     }
 
@@ -500,7 +500,7 @@ public bool IsRegistered(Type type, string name = null)
     private void AssertNotResolved(RegistrationKey interfaceType)
     {
         if (_resolvedKeys.Contains(interfaceType))
-            throw new ObjectContainerException("An object has been resolved for this interface already.", null);
+            throw new ObjectContainerException($"An object has already been resolved for the interface \"{interfaceType}\".", null);
     }
 
     private void ClearRegistrations(RegistrationKey registrationKey)

Tests/Reqnroll.RuntimeTests/BoDi/RegisterTypeTests.cs

@@ -65,7 +65,8 @@ public void ShouldNotAllowOverrideRegistrationAfterResolve()
 
             // when 
             Action act = () => container.RegisterTypeAs<SimpleClassWithDefaultCtor, IInterface1>();
-            act.Should().ThrowExactly<ObjectContainerException>();
+            act.Should().ThrowExactly<ObjectContainerException>()
+                .And.Message.Should().Contain("IInterface1");
         }
 
         [Fact]