Don't throw exception for parameters with custom binding source (#59035)

* Don't through exception for parameters with custom binding source

* Default to ParameterLocation.Query for ambiguous source

Author: captainsafia

src/OpenApi/src/Services/OpenApiDocumentService.cs

@@ -410,7 +410,7 @@ private async Task<OpenApiResponse> GetResponseAsync(
                     "Query" => ParameterLocation.Query,
                     "Header" => ParameterLocation.Header,
                     "Path" => ParameterLocation.Path,
-                    _ => throw new InvalidOperationException($"Unsupported parameter source: {parameter.Source.Id}")
+                    _ => ParameterLocation.Query
                 },
                 Required = IsRequired(parameter),
                 Schema = await _componentService.GetOrCreateSchemaAsync(GetTargetType(description, parameter), scopedServiceProvider, schemaTransformers, parameter, cancellationToken: cancellationToken),

src/OpenApi/test/Microsoft.AspNetCore.OpenApi.Tests/Services/OpenApiDocumentService/OpenApiDocumentServiceTests.Parameters.cs

@@ -4,6 +4,7 @@
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.OpenApi.Models;
 
 public partial class OpenApiDocumentServiceTests : OpenApiDocumentServiceTestBase
@@ -190,4 +191,29 @@ await VerifyOpenApiDocument(builder, document =>
             Assert.Null(document.Paths["/api/content-type-lower"].Operations[OperationType.Get].Parameters);
         });
     }
+
+    [Fact]
+    public async Task GetOpenApiParameters_ToleratesCustomBindingSource()
+    {
+        var action = CreateActionDescriptor(nameof(ActionWithCustomBinder));
+
+        await VerifyOpenApiDocument(action, document =>
+        {
+            var operation = document.Paths["/custom-binding"].Operations[OperationType.Get];
+            var parameter = Assert.Single(operation.Parameters);
+            Assert.Equal("model", parameter.Name);
+            Assert.Equal(ParameterLocation.Query, parameter.In);
+        });
+    }
+
+    [Route("/custom-binding")]
+    private void ActionWithCustomBinder([ModelBinder(BinderType = typeof(CustomBinder))] Todo model) { }
+
+    public class CustomBinder : IModelBinder
+    {
+        public Task BindModelAsync(ModelBindingContext bindingContext)
+        {
+            return Task.CompletedTask;
+        }
+    }
 }