Expands navigation properties of derived types only if declaring navigation property is a containment

src/Microsoft.OpenApi.OData.Reader/Edm/ODataPathProvider.cs

@@ -559,21 +559,34 @@ bool filter(IEdmStructuredType x) =>
                                 .OfType<IEdmStructuredType>()
                                 .ToArray();
 
-            foreach(var targetType in targetTypes)
+            foreach (var targetType in targetTypes)
             {
-                var castPath = currentPath.Clone();
                 var targetTypeSegment = new ODataTypeCastSegment(targetType);
 
+                if (currentPath.Segments.Any(x => x.Identifier.Equals(targetTypeSegment.Identifier)))
+                {
+                    // In case we have expanded a derived type's navigation property
+                    // and we are in a cyclic loop where the expanded navigation property
+                    // has a derived type that has already been added to the path.
+                    continue;
+                }
+
+                var castPath = currentPath.Clone();
                 castPath.Push(targetTypeSegment);
                 AppendPath(castPath);
-                if(targetsMany) 
+                if (targetsMany)
                 {
                     CreateCountPath(castPath, convertSettings);
                 }
                 else
                 {
                     if (convertSettings.ExpandDerivedTypesNavigationProperties)
                     {
+                        if (annotable is IEdmNavigationProperty navigationProperty && !navigationProperty.ContainsTarget)
+                        {
+                            continue;
+                        }
+
                         foreach (var declaredNavigationProperty in targetType.DeclaredNavigationProperties())
                         {
                             RetrieveNavigationPropertyPaths(declaredNavigationProperty, null, castPath, convertSettings);

src/Microsoft.OpenApi.OData.Reader/Microsoft.OpenAPI.OData.Reader.csproj

@@ -15,7 +15,7 @@
     <TargetFrameworks>netstandard2.0</TargetFrameworks>
     <PackageId>Microsoft.OpenApi.OData</PackageId>
     <SignAssembly>true</SignAssembly>
-    <Version>1.2.0-preview5</Version>
+    <Version>1.2.0-preview6</Version>
     <Description>This package contains the codes you need to convert OData CSDL to Open API Document of Model.</Description>
     <Copyright>© Microsoft Corporation. All rights reserved.</Copyright>
     <PackageTags>Microsoft OpenApi OData EDM</PackageTags>
@@ -27,6 +27,7 @@
 - Adds create and update operations to non-containment navigation properties when restrictions annotations are explicitly set to true #265
 - Generate odata.nextLink and odata.deltaLink properties on delta functions response schemas #285
 - Omits paths with PathItems without any operation #148
+- Expands navigation properties of derived types only if declaring navigation property is a containment #269
     </PackageReleaseNotes>
     <AssemblyName>Microsoft.OpenApi.OData.Reader</AssemblyName>
     <AssemblyOriginatorKeyFile>..\..\tool\Microsoft.OpenApi.OData.snk</AssemblyOriginatorKeyFile>

test/Microsoft.OpenAPI.OData.Reader.Tests/Edm/ODataPathProviderTests.cs

@@ -40,18 +40,15 @@ public void GetPathsForGraphBetaModelReturnsAllPaths()
         {
             // Arrange
             IEdmModel model = EdmModelHelper.GraphBetaModel;
-            var settings = new OpenApiConvertSettings()
-            {
-                ExpandDerivedTypesNavigationProperties = false
-            };
             ODataPathProvider provider = new ODataPathProvider();
+            var settings = new OpenApiConvertSettings();
 
             // Act
             var paths = provider.GetPaths(model, settings);
 
             // Assert
             Assert.NotNull(paths);
-            Assert.Equal(13836, paths.Count());
+            Assert.Equal(18316, paths.Count());
         }
 
         [Fact]
@@ -63,7 +60,6 @@ public void GetPathsForGraphBetaModelWithDerivedTypesConstraintReturnsAllPaths()
             var settings = new OpenApiConvertSettings
             {
                 RequireDerivedTypesConstraintForBoundOperations = true,
-                ExpandDerivedTypesNavigationProperties = false,
                 AppendBoundOperationsOnDerivedTypeCastSegments = true
             };
 
@@ -72,7 +68,7 @@ public void GetPathsForGraphBetaModelWithDerivedTypesConstraintReturnsAllPaths()
 
             // Assert
             Assert.NotNull(paths);
-            Assert.Equal(15293, paths.Count());
+            Assert.Equal(19773, paths.Count());
         }
 
         [Fact]