Handle the case for unsuccessful custom analyzer registration + change e2e tests

src/Build/BuildCheck/Acquisition/BuildCheckAcquisitionModule.cs

@@ -42,18 +42,17 @@ public List<BuildAnalyzerFactory> CreateBuildAnalyzerFactories(AnalyzerAcquisiti
             assembly = Assembly.LoadFrom(analyzerAcquisitionData.AssemblyPath);
 #endif
 
-            IEnumerable<Type> analyzerTypes = assembly.GetExportedTypes().Where(t => typeof(BuildAnalyzer).IsAssignableFrom(t));
+            IList<Type> availableTypes = assembly.GetExportedTypes();
+            IList<Type> analyzerTypes = availableTypes.Where(t => typeof(BuildAnalyzer).IsAssignableFrom(t)).ToArray();
 
-            foreach (Type analyzerType in analyzerTypes)
+            foreach (Type analyzerCandidate in analyzerTypes)
             {
-                if (Activator.CreateInstance(analyzerType) is BuildAnalyzer instance)
-                {
-                    analyzersFactories.Add(() => instance);
-                }
-                else
-                {
-                    throw new InvalidOperationException($"Failed to create an instance of type {analyzerType.FullName} as BuildAnalyzer.");
-                }
+                analyzersFactories.Add(() => (BuildAnalyzer)Activator.CreateInstance(analyzerCandidate)!);
+            }
+
+            if (availableTypes.Count != analyzerTypes.Count)
+            {
+                availableTypes.Except(analyzerTypes).ToList().ForEach(t => _loggingService.LogComment(buildEventContext, MessageImportance.Normal, "CustomAnalyzerBaseTypeNotAssignable", t.Name, t.Assembly));
             }
         }
         catch (ReflectionTypeLoadException ex)

src/Build/Resources/Strings.resx

@@ -2111,6 +2111,10 @@ Utilization:          {0} Average Utilization: {1:###.0}</value>
     <value>Failed to find the specified custom analyzer assembly: {0}. Please check if it exists.</value>
     <comment>The message is emitted when the custom analyzer assembly can not be found.</comment>
   </data>
+  <data name="CustomAnalyzerBaseTypeNotAssignable" xml:space="preserve">
+    <value>Failed to load the custom analyzer type: {0} from the assembly: {1}. Make sure it inherits the Microsoft.Build.Experimental.BuildCheck.BuildAnalyzer base class. If it is not intended to be a custom analyzer, than it should not be exposed. More info: https://github.com/dotnet/msbuild/blob/main/documentation/specs/proposed/BuildCheck-Architecture.md#acquisition</value>
+    <comment>The message is emitted when the custom analyzer assembly can not be successfully registered.</comment>
+  </data>
   <data name="TaskAssemblyLocationMismatch" xml:space="preserve">
     <value>Task assembly was loaded from '{0}' while the desired location was '{1}'.</value>
   </data>