Api Explorer: multiple complex properties

src/Mvc/Mvc.ApiExplorer/src/DefaultApiDescriptionProvider.cs

@@ -585,6 +585,7 @@ namespace Microsoft.AspNetCore.Mvc.ApiExplorer
                     if (Visited.Add(key))
                     {
                         Visit(propertyContext, source ?? ambientSource, newContainerName);
+                        Visited.Remove(key);
                     }
                     else
                     {

src/Mvc/Mvc.ApiExplorer/test/DefaultApiDescriptionProviderTest.cs

@@ -1485,6 +1485,66 @@ namespace Microsoft.AspNetCore.Mvc.Description
             Assert.Equal(typeof(decimal), productPrice.Type);
         }
 
+        [Fact]
+        public void GetApiDescription_ParameterDescription_DuplicatePropertiesWithChildren_ExpandBoth()
+        {
+            // Arrange
+            var action = CreateActionDescriptor(nameof(AcceptsMultipleProperties));
+            var parameterDescriptor = action.Parameters.Single();
+
+            // Act
+            var descriptions = GetApiDescriptions(action);
+
+            // Assert
+            var description = Assert.Single(descriptions);
+            Assert.Equal(4, description.ParameterDescriptions.Count);
+
+            var parentNames = new[] { "Parent1", "Parent2" };
+
+            foreach (var parentName in parentNames)
+            {
+                var id = Assert.Single(description.ParameterDescriptions, p => p.Name == $"{parentName}.Child.Id");
+                Assert.Same(BindingSource.Query, id.Source);
+                Assert.Equal(typeof(int), id.Type);
+
+                var name = Assert.Single(description.ParameterDescriptions, p => p.Name == $"{parentName}.Child.Name");
+                Assert.Same(BindingSource.Query, name.Source);
+                Assert.Equal(typeof(string), name.Type);
+            }
+        }
+
+        [Fact]
+        public void GetApiDescription_ParameterDescription_DuplicatePropertiesWithChildren_Nested_ExpandAll()
+        {
+            // Arrange
+            var action = CreateActionDescriptor(nameof(AcceptsMultiplePropertiesNested));
+            var parameterDescriptor = action.Parameters.Single();
+
+            // Act
+            var descriptions = GetApiDescriptions(action);
+
+            // Assert
+            var description = Assert.Single(descriptions);
+            Assert.Equal(8, description.ParameterDescriptions.Count);
+
+            var groupNames = new[] { "Group1", "Group2" };
+            var parentNames = new[] { "Parent1", "Parent2" };
+
+            foreach (var groupName in groupNames)
+            {
+                foreach (var parentName in parentNames)
+                {
+                    var id = Assert.Single(description.ParameterDescriptions, p => p.Name == $"{groupName}.{parentName}.Child.Id");
+                    Assert.Same(BindingSource.Query, id.Source);
+                    Assert.Equal(typeof(int), id.Type);
+
+                    var name = Assert.Single(description.ParameterDescriptions, p => p.Name == $"{groupName}.{parentName}.Child.Name");
+                    Assert.Same(BindingSource.Query, name.Source);
+                    Assert.Equal(typeof(string), name.Type);
+                }
+            }
+        }
+
         [Fact]
         public void GetApiDescription_ParameterDescription_BreaksCycles()
         {
@@ -2081,6 +2141,14 @@ namespace Microsoft.AspNetCore.Mvc.Description
         {
         }
 
+        private void AcceptsMultipleProperties([FromQuery]MultipleProperties model)
+        {
+        }
+
+        private void AcceptsMultiplePropertiesNested([FromQuery]MultiplePropertiesContainer model)
+        {
+        }
+
         private void ParameterDefaultValue(int value = 10) { }
 
         private class TestController
@@ -2237,6 +2305,23 @@ namespace Microsoft.AspNetCore.Mvc.Description
             public int Id { get; set; }
         }
 
+        private class MultiplePropertiesContainer
+        {
+            public MultipleProperties Group1 { get; set; }
+            public MultipleProperties Group2 { get; set; }
+        }
+
+        private class MultipleProperties
+        {
+            public Parent Parent1 { get; set; }
+            public Parent Parent2 { get; set; }
+        }
+
+        private class Parent
+        {
+            public Child Child { get; set; }
+        }
+
         private class MockInputFormatter : TextInputFormatter
         {
             public List<Type> SupportedTypes { get; } = new List<Type>();