Improve S6964: Dont try to raise issue when Model and Controller are in different projects

analyzers/src/SonarAnalyzer.CSharp/Rules/AspNet/AvoidUnderPosting.cs

@@ -62,7 +62,7 @@ private static void ProcessControllerMethods(SonarSyntaxNodeReportingContext con
         {
             var modelParameterTypes = method.Parameters
                 .Where(x => !HasValidateNeverAttribute(x))
-                .SelectMany(x => RelatedTypesToExamine(x.Type))
+                .SelectMany(x => RelatedTypesToExamine(x.Type, method.ContainingType))
                 .Distinct();
             foreach (var modelParameterType in modelParameterTypes)
             {
@@ -132,13 +132,14 @@ private static void GetAllDeclaredProperties(ITypeSymbol type, ConcurrentDiction
         }
     }
 
-    private static IEnumerable<INamedTypeSymbol> RelatedTypesToExamine(ITypeSymbol type) =>
+    // We only consider Model types that are in the same assembly as the Controller, because Roslyn can't raise an issue when the location is in a different assembly than the one being analyzed.
+    private static IEnumerable<INamedTypeSymbol> RelatedTypesToExamine(ITypeSymbol type, ITypeSymbol controllerType) =>
         type switch
         {
-            IArrayTypeSymbol array => RelatedTypesToExamine(array.ElementType),
+            IArrayTypeSymbol array => RelatedTypesToExamine(array.ElementType, controllerType),
             INamedTypeSymbol collection when collection.DerivesOrImplements(KnownType.System_Collections_Generic_IEnumerable_T) =>
-                collection.TypeArguments.SelectMany(RelatedTypesToExamine),
-            INamedTypeSymbol namedType => [namedType],
+                collection.TypeArguments.SelectMany(x => RelatedTypesToExamine(x, controllerType)),
+            INamedTypeSymbol namedType when type.IsInSameAssembly(controllerType) => [namedType],
             _ => []
         };
 

analyzers/tests/SonarAnalyzer.Test/Rules/AspNet/AvoidUnderPostingTest.cs

@@ -27,14 +27,15 @@ namespace SonarAnalyzer.Test.Rules;
 [TestClass]
 public class AvoidUnderPostingTest
 {
-    private readonly VerifierBuilder builder = new VerifierBuilder<AvoidUnderPosting>()
-            .WithBasePath("AspNet")
-            .AddReferences([
+    private static readonly IEnumerable<MetadataReference> AspNetReferences = [
                 AspNetCoreMetadataReference.MicrosoftAspNetCoreMvcAbstractions,
                 AspNetCoreMetadataReference.MicrosoftAspNetCoreMvcCore,
                 AspNetCoreMetadataReference.MicrosoftAspNetCoreMvcViewFeatures,
-                ..NuGetMetadataReference.SystemComponentModelAnnotations(Constants.NuGetLatestVersion)
-            ]);
+                ..NuGetMetadataReference.SystemComponentModelAnnotations(Constants.NuGetLatestVersion)];
+
+    private readonly VerifierBuilder builder = new VerifierBuilder<AvoidUnderPosting>()
+            .WithBasePath("AspNet")
+            .AddReferences(AspNetReferences);
 
     [TestMethod]
     public void AvoidUnderPosting_CSharp() =>
@@ -103,6 +104,43 @@ public class ControllerClass : Controller
                 [{{attribute}}] public IActionResult Create(Model model) => View(model);
             }
             """).Verify();
+
+    [TestMethod]
+    public void AvoidUnderPosting_ModelInDifferentProject_CSharp()
+    {
+        const string modelCode = """
+            namespace Models
+            {
+                public class Person
+                {
+                    public int Age { get; set; }    // FN - Roslyn can't raise an issue when the location is in different project than the one being analyzed
+                }
+            }
+            """;
+        const string controllerCode = """
+            using Microsoft.AspNetCore.Mvc;
+            using Models;
+
+            namespace Controllers
+            {
+                public class PersonController : Controller
+                {
+                    [HttpPost] public IActionResult Post(Person person) => View(person);
+                }
+            }
+            """;
+        var solution = SolutionBuilder.Create()
+            .AddProject(AnalyzerLanguage.CSharp)
+            .AddSnippet(modelCode)
+            .Solution
+            .AddProject(AnalyzerLanguage.CSharp)
+            .AddProjectReference(x => x.ProjectIds[0])
+            .AddReferences(AspNetReferences)
+            .AddSnippet(controllerCode)
+            .Solution;
+        var compiledAspNetProject = solution.Compile()[1];
+        DiagnosticVerifier.Verify(compiledAspNetProject, new AvoidUnderPosting());
+    }
 }
 
 #endif