Fixes #1397: Conventional routing cannot identify the endpoint for action to query property without the key

src/Microsoft.AspNetCore.OData/Extensions/ActionModelExtensions.cs

@@ -103,6 +103,11 @@ public static bool HasODataKeyParameter(this ActionModel action, IEdmEntityType
 
         // TODO: shall we make sure the type is matching?
         var keys = entityType.Key().ToArray();
+        if (keys.Length == 0)
+        {
+            return false;
+        }
+
         if (keys.Length == 1)
         {
             // one key

test/Microsoft.AspNetCore.OData.Tests/Routing/Conventions/NavigationRoutingConventionTests.cs

@@ -175,6 +175,26 @@ public void NavigationRoutingConventionAddDollarCountAsExpectedBasedOnConfigurat
         }
     }
 
+    [Theory]
+    [InlineData(0)]
+    [InlineData(1)]
+    [InlineData(2)]
+    public void NavigationRoutingConventionOnSingletonWithoutKeyDefinedOnEntityTypeAsExpectedBasedOnConfiguration(int paramerterCount)
+    {
+        // Arrange
+        ControllerModel controller = ControllerModelHelpers.BuildControllerModelWithAllActions<MainSupplierController>();
+        ActionModel action = controller.Actions.First(a => a.ActionName == "GetCustomers" && a.Parameters.Count == paramerterCount);
+
+        ODataControllerActionContext context = ODataControllerActionContextHelpers.BuildContext(string.Empty, EdmModel, controller);
+        context.Action = action;
+
+        // Act
+        bool returnValue = NavigationConvention.AppliesToAction(context);
+        Assert.True(returnValue);
+
+        Assert.Equal(["/MainSupplier/Customers", "/MainSupplier/Customers/$count"], action.Selectors.Select(s => s.AttributeRouteModel.Template));
+    }
+
     [Theory]
     [InlineData("PostToName")]
     [InlineData("Get")]
@@ -285,6 +305,23 @@ private static IEdmModel GetEdmModel()
         customers.AddNavigationTarget(subOrderNavProp, orders, new EdmPathExpression("NS.VipCustomer/SubOrder"));
         me.AddNavigationTarget(subOrderNavProp, orders, new EdmPathExpression("NS.VipCustomer/SubOrder"));
 
+        // Let's build a singleton using an entity type without a key
+        // So 'Supplier' doesn't contain a key by design.
+        EdmEntityType supplier = new EdmEntityType("NS", "Supplier");
+        supplier.AddStructuralProperty("Name", EdmPrimitiveTypeKind.String);
+        model.AddElement(supplier);
+
+        supplier.AddUnidirectionalNavigation(
+            new EdmNavigationPropertyInfo
+            {
+                Name = "Customers",
+                TargetMultiplicity = EdmMultiplicity.Many,
+                Target = customer,
+                ContainsTarget = true
+            });
+
+        container.AddSingleton("MainSupplier", supplier);
+
         return model;
     }
 
@@ -333,6 +370,18 @@ public void PatchToSubOrderFromVipCustomer(CancellationToken cancellation)
         { }
     }
 
+    private class MainSupplierController
+    {
+        public void GetCustomers(int key, CancellationToken cancellation)
+        { }
+
+        public void GetCustomers(int key)
+        { }
+
+        public void GetCustomers()
+        { }
+    }
+
     private class UnknownController
     { }
 }

test/Microsoft.AspNetCore.OData.Tests/Routing/Conventions/PropertyRoutingConventionTests.cs

@@ -219,6 +219,25 @@ public void PropertyRoutingConventionAddDollarCountAsExpectedBasedOnConfiguratio
         }
     }
 
+    [Theory]
+    [InlineData(0)]
+    [InlineData(1)]
+    public void PropertyRoutingConventionOnSingletonWithoutKeyDefinedOnEntityTypeAsExpectedBasedOnConfiguration(int paramerterCount)
+    {
+        // Arrange
+        ControllerModel controller = ControllerModelHelpers.BuildControllerModelWithAllActions<MainSupplierController>();
+        ActionModel action = controller.Actions.First(a => a.ActionName == "GetName" && a.Parameters.Count == paramerterCount);
+
+        ODataControllerActionContext context = ODataControllerActionContextHelpers.BuildContext(string.Empty, EdmModel, controller);
+        context.Action = action;
+
+        // Act
+        bool returnValue = PropertyConvention.AppliesToAction(context);
+        Assert.True(returnValue);
+
+        Assert.Equal(["/MainSupplier/Name", "/MainSupplier/Name/$value"], action.Selectors.Select(s => s.AttributeRouteModel.Template));
+    }
+
     [Theory]
     [InlineData("PostToName")]
     [InlineData("Get")]
@@ -294,6 +313,13 @@ private static IEdmModel GetEdmModel()
         container.AddEntitySet("AnotherCustomers", customer);
         container.AddSingleton("Me", customer);
         model.AddElement(container);
+
+        // Let's build a singleton using an entity type without a key.
+        // So 'Supplier' doesn't contain a key by design.
+        EdmEntityType supplier = new EdmEntityType("NS", "Supplier");
+        supplier.AddStructuralProperty("Name", EdmPrimitiveTypeKind.String);
+        model.AddElement(supplier);
+        container.AddSingleton("MainSupplier", supplier);
         return model;
     }
 
@@ -373,6 +399,18 @@ public void PostToSubLocationsOfUsAddressFromVipCustomer()
         { }
     }
 
+    private class MainSupplierController
+    {
+        public void GetName()
+        { }
+
+        public void GetName(int key)
+        {
+            // Be noted, the type of 'MainSupplier' doesn't contain a key.
+            // So, conventional routing doesn't care about the parameters.
+        }
+    }
+
     private class AnotherCustomersController
     {
         public void PostToName(string keyLastName, string keyFirstName)