Fix property lookup to support inheritance in pagination response models

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/src/Providers/CollectionResultDefinition.cs

@@ -143,7 +143,7 @@ private CSharpType GetNextPagePropertyType()
             PropertyProvider? property = null;
             for (int i = 0; i < NextPagePropertySegments.Count; i++)
             {
-                property = model.Properties.First(p => p.WireInfo?.SerializedName == NextPagePropertySegments[i]);
+                property = FindPropertyInModelHierarchy(model, NextPagePropertySegments[i]);
 
                 if (i < NextPagePropertySegments.Count - 1)
                 {
@@ -154,6 +154,29 @@ private CSharpType GetNextPagePropertyType()
             return property!.Type;
         }
 
+        /// <summary>
+        /// Searches for a property with the specified serialized name in the model and its base models.
+        /// </summary>
+        private PropertyProvider FindPropertyInModelHierarchy(TypeProvider model, string serializedName)
+        {
+            // First, try to find the property in the current model
+            var property = model.Properties.FirstOrDefault(p => p.WireInfo?.SerializedName == serializedName);
+            if (property != null)
+            {
+                return property;
+            }
+
+            // If not found, search in the base model hierarchy
+            if (model is ModelProvider modelProvider && modelProvider.BaseModelProvider != null)
+            {
+                return FindPropertyInModelHierarchy(modelProvider.BaseModelProvider, serializedName);
+            }
+
+            // If not found anywhere, throw an exception with a helpful message
+            throw new InvalidOperationException(
+                $"Property with serialized name '{serializedName}' not found in model '{model.Name}' or its base models.");
+        }
+
         protected override string BuildRelativeFilePath() => Path.Combine("src", "Generated", "CollectionResults", $"{Name}.cs");
 
         protected override string BuildNamespace() => Client.Type.Namespace;

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/test/Providers/CollectionResultDefinitions/NextLinkTests.cs

@@ -238,6 +238,62 @@ public void UsesValidFieldIdentifierNames()
             Assert.IsTrue(fields.Any(f => f.Name == "_foo"));
         }
 
+        [Test]
+        public void InheritedNextLinkInBody()
+        {
+            CreatePagingOperationWithInheritedNextLink(InputResponseLocation.Body);
+
+            var collectionResultDefinition = ScmCodeModelGenerator.Instance.OutputLibrary.TypeProviders.FirstOrDefault(
+                t => t is CollectionResultDefinition && t.Name == "CatClientGetCatsCollectionResult");
+            Assert.IsNotNull(collectionResultDefinition);
+
+            var writer = new TypeProviderWriter(collectionResultDefinition!);
+            var file = writer.Write();
+            Assert.AreEqual(Helpers.GetExpectedFromFile(), file.Content);
+        }
+
+        [Test]
+        public void InheritedNextLinkInBodyAsync()
+        {
+            CreatePagingOperationWithInheritedNextLink(InputResponseLocation.Body);
+
+            var collectionResultDefinition = ScmCodeModelGenerator.Instance.OutputLibrary.TypeProviders.FirstOrDefault(
+                t => t is CollectionResultDefinition && t.Name == "CatClientGetCatsAsyncCollectionResult");
+            Assert.IsNotNull(collectionResultDefinition);
+
+            var writer = new TypeProviderWriter(collectionResultDefinition!);
+            var file = writer.Write();
+            Assert.AreEqual(Helpers.GetExpectedFromFile(), file.Content);
+        }
+
+        [Test]
+        public void InheritedNextLinkInBodyOfT()
+        {
+            CreatePagingOperationWithInheritedNextLink(InputResponseLocation.Body);
+
+            var collectionResultDefinition = ScmCodeModelGenerator.Instance.OutputLibrary.TypeProviders.FirstOrDefault(
+                t => t is CollectionResultDefinition && t.Name == "CatClientGetCatsCollectionResultOfT");
+            Assert.IsNotNull(collectionResultDefinition);
+
+            var writer = new TypeProviderWriter(collectionResultDefinition!);
+            var file = writer.Write();
+            Assert.AreEqual(Helpers.GetExpectedFromFile(), file.Content);
+        }
+
+        [Test]
+        public void InheritedNextLinkInBodyOfTAsync()
+        {
+            CreatePagingOperationWithInheritedNextLink(InputResponseLocation.Body);
+
+            var collectionResultDefinition = ScmCodeModelGenerator.Instance.OutputLibrary.TypeProviders.FirstOrDefault(
+                t => t is CollectionResultDefinition && t.Name == "CatClientGetCatsAsyncCollectionResultOfT");
+            Assert.IsNotNull(collectionResultDefinition);
+
+            var writer = new TypeProviderWriter(collectionResultDefinition!);
+            var file = writer.Write();
+            Assert.AreEqual(Helpers.GetExpectedFromFile(), file.Content);
+        }
+
         private static void CreatePagingOperation(InputResponseLocation responseLocation, bool isNested = false)
         {
             var inputModel = InputFactory.Model("cat", properties:
@@ -267,5 +323,29 @@ private static void CreatePagingOperation(InputResponseLocation responseLocation
 
             MockHelpers.LoadMockGenerator(inputModels: () => [inputModel], clients: () => [client]);
         }
+
+        private static void CreatePagingOperationWithInheritedNextLink(InputResponseLocation responseLocation)
+        {
+            var inputModel = InputFactory.Model("cat", properties:
+            [
+                InputFactory.Property("color", InputPrimitiveType.String, isRequired: true),
+            ]);
+
+            // Create the base model with nextLink property
+            var nextCatProperty = InputFactory.Property("nextCat", InputPrimitiveType.Url);
+            var baseModel = InputFactory.Model("basePage", properties: [nextCatProperty]);
+
+            // Create the derived model that inherits from base and adds cats property
+            var catsProperty = InputFactory.Property("cats", InputFactory.Array(inputModel));
+            var derivedModel = InputFactory.Model("page", properties: [catsProperty], baseModel: baseModel);
+
+            var pagingMetadata = InputFactory.NextLinkPagingMetadata(["cats"], ["nextCat"], responseLocation);
+            var response = InputFactory.OperationResponse([200], derivedModel);
+            var operation = InputFactory.Operation("getCats", responses: [response]);
+            var inputServiceMethod = InputFactory.PagingServiceMethod("getCats", operation, pagingMetadata: pagingMetadata);
+            var client = InputFactory.Client("catClient", methods: [inputServiceMethod]);
+
+            MockHelpers.LoadMockGenerator(inputModels: () => [inputModel, baseModel, derivedModel], clients: () => [client]);
+        }
     }
 }

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/test/Providers/CollectionResultDefinitions/TestData/NextLinkTests/InheritedNextLinkInBody.cs

@@ -0,0 +1,55 @@
+// <auto-generated/>
+
+#nullable disable
+
+using System;
+using System.ClientModel;
+using System.ClientModel.Primitives;
+using System.Collections.Generic;
+using Sample.Models;
+
+namespace Sample
+{
+    internal partial class CatClientGetCatsCollectionResult : global::System.ClientModel.Primitives.CollectionResult
+    {
+        private readonly global::Sample.CatClient _client;
+        private readonly global::System.ClientModel.Primitives.RequestOptions _options;
+
+        public CatClientGetCatsCollectionResult(global::Sample.CatClient client, global::System.ClientModel.Primitives.RequestOptions options)
+        {
+            _client = client;
+            _options = options;
+        }
+
+        public override global::System.Collections.Generic.IEnumerable<global::System.ClientModel.ClientResult> GetRawPages()
+        {
+            global::System.ClientModel.Primitives.PipelineMessage message = _client.CreateGetCatsRequest(_options);
+            global::System.Uri nextPageUri = null;
+            while (true)
+            {
+                global::System.ClientModel.ClientResult result = global::System.ClientModel.ClientResult.FromResponse(_client.Pipeline.ProcessMessage(message, _options));
+                yield return result;
+
+                nextPageUri = ((global::Sample.Models.Page)result).NextCat;
+                if ((nextPageUri == null))
+                {
+                    yield break;
+                }
+                message = _client.CreateNextGetCatsRequest(nextPageUri, _options);
+            }
+        }
+
+        public override global::System.ClientModel.ContinuationToken GetContinuationToken(global::System.ClientModel.ClientResult page)
+        {
+            global::System.Uri nextPage = ((global::Sample.Models.Page)page).NextCat;
+            if ((nextPage != null))
+            {
+                return global::System.ClientModel.ContinuationToken.FromBytes(global::System.BinaryData.FromString(nextPage.AbsoluteUri));
+            }
+            else
+            {
+                return null;
+            }
+        }
+    }
+}

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/test/Providers/CollectionResultDefinitions/TestData/NextLinkTests/InheritedNextLinkInBodyAsync.cs

@@ -0,0 +1,55 @@
+// <auto-generated/>
+
+#nullable disable
+
+using System;
+using System.ClientModel;
+using System.ClientModel.Primitives;
+using System.Collections.Generic;
+using Sample.Models;
+
+namespace Sample
+{
+    internal partial class CatClientGetCatsAsyncCollectionResult : global::System.ClientModel.Primitives.AsyncCollectionResult
+    {
+        private readonly global::Sample.CatClient _client;
+        private readonly global::System.ClientModel.Primitives.RequestOptions _options;
+
+        public CatClientGetCatsAsyncCollectionResult(global::Sample.CatClient client, global::System.ClientModel.Primitives.RequestOptions options)
+        {
+            _client = client;
+            _options = options;
+        }
+
+        public override async global::System.Collections.Generic.IAsyncEnumerable<global::System.ClientModel.ClientResult> GetRawPagesAsync()
+        {
+            global::System.ClientModel.Primitives.PipelineMessage message = _client.CreateGetCatsRequest(_options);
+            global::System.Uri nextPageUri = null;
+            while (true)
+            {
+                global::System.ClientModel.ClientResult result = global::System.ClientModel.ClientResult.FromResponse(await _client.Pipeline.ProcessMessageAsync(message, _options).ConfigureAwait(false));
+                yield return result;
+
+                nextPageUri = ((global::Sample.Models.Page)result).NextCat;
+                if ((nextPageUri == null))
+                {
+                    yield break;
+                }
+                message = _client.CreateNextGetCatsRequest(nextPageUri, _options);
+            }
+        }
+
+        public override global::System.ClientModel.ContinuationToken GetContinuationToken(global::System.ClientModel.ClientResult page)
+        {
+            global::System.Uri nextPage = ((global::Sample.Models.Page)page).NextCat;
+            if ((nextPage != null))
+            {
+                return global::System.ClientModel.ContinuationToken.FromBytes(global::System.BinaryData.FromString(nextPage.AbsoluteUri));
+            }
+            else
+            {
+                return null;
+            }
+        }
+    }
+}

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/test/Providers/CollectionResultDefinitions/TestData/NextLinkTests/InheritedNextLinkInBodyOfT.cs

@@ -0,0 +1,60 @@
+// <auto-generated/>
+
+#nullable disable
+
+using System;
+using System.ClientModel;
+using System.ClientModel.Primitives;
+using System.Collections.Generic;
+using Sample.Models;
+
+namespace Sample
+{
+    internal partial class CatClientGetCatsCollectionResultOfT : global::System.ClientModel.CollectionResult<global::Sample.Models.Cat>
+    {
+        private readonly global::Sample.CatClient _client;
+        private readonly global::System.ClientModel.Primitives.RequestOptions _options;
+
+        public CatClientGetCatsCollectionResultOfT(global::Sample.CatClient client, global::System.ClientModel.Primitives.RequestOptions options)
+        {
+            _client = client;
+            _options = options;
+        }
+
+        public override global::System.Collections.Generic.IEnumerable<global::System.ClientModel.ClientResult> GetRawPages()
+        {
+            global::System.ClientModel.Primitives.PipelineMessage message = _client.CreateGetCatsRequest(_options);
+            global::System.Uri nextPageUri = null;
+            while (true)
+            {
+                global::System.ClientModel.ClientResult result = global::System.ClientModel.ClientResult.FromResponse(_client.Pipeline.ProcessMessage(message, _options));
+                yield return result;
+
+                nextPageUri = ((global::Sample.Models.Page)result).NextCat;
+                if ((nextPageUri == null))
+                {
+                    yield break;
+                }
+                message = _client.CreateNextGetCatsRequest(nextPageUri, _options);
+            }
+        }
+
+        public override global::System.ClientModel.ContinuationToken GetContinuationToken(global::System.ClientModel.ClientResult page)
+        {
+            global::System.Uri nextPage = ((global::Sample.Models.Page)page).NextCat;
+            if ((nextPage != null))
+            {
+                return global::System.ClientModel.ContinuationToken.FromBytes(global::System.BinaryData.FromString(nextPage.AbsoluteUri));
+            }
+            else
+            {
+                return null;
+            }
+        }
+
+        protected override global::System.Collections.Generic.IEnumerable<global::Sample.Models.Cat> GetValuesFromPage(global::System.ClientModel.ClientResult page)
+        {
+            return ((global::Sample.Models.Page)page).Cats;
+        }
+    }
+}

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/test/Providers/CollectionResultDefinitions/TestData/NextLinkTests/InheritedNextLinkInBodyOfTAsync.cs

@@ -0,0 +1,65 @@
+// <auto-generated/>
+
+#nullable disable
+
+using System;
+using System.ClientModel;
+using System.ClientModel.Primitives;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Sample.Models;
+
+namespace Sample
+{
+    internal partial class CatClientGetCatsAsyncCollectionResultOfT : global::System.ClientModel.AsyncCollectionResult<global::Sample.Models.Cat>
+    {
+        private readonly global::Sample.CatClient _client;
+        private readonly global::System.ClientModel.Primitives.RequestOptions _options;
+
+        public CatClientGetCatsAsyncCollectionResultOfT(global::Sample.CatClient client, global::System.ClientModel.Primitives.RequestOptions options)
+        {
+            _client = client;
+            _options = options;
+        }
+
+        public override async global::System.Collections.Generic.IAsyncEnumerable<global::System.ClientModel.ClientResult> GetRawPagesAsync()
+        {
+            global::System.ClientModel.Primitives.PipelineMessage message = _client.CreateGetCatsRequest(_options);
+            global::System.Uri nextPageUri = null;
+            while (true)
+            {
+                global::System.ClientModel.ClientResult result = global::System.ClientModel.ClientResult.FromResponse(await _client.Pipeline.ProcessMessageAsync(message, _options).ConfigureAwait(false));
+                yield return result;
+
+                nextPageUri = ((global::Sample.Models.Page)result).NextCat;
+                if ((nextPageUri == null))
+                {
+                    yield break;
+                }
+                message = _client.CreateNextGetCatsRequest(nextPageUri, _options);
+            }
+        }
+
+        public override global::System.ClientModel.ContinuationToken GetContinuationToken(global::System.ClientModel.ClientResult page)
+        {
+            global::System.Uri nextPage = ((global::Sample.Models.Page)page).NextCat;
+            if ((nextPage != null))
+            {
+                return global::System.ClientModel.ContinuationToken.FromBytes(global::System.BinaryData.FromString(nextPage.AbsoluteUri));
+            }
+            else
+            {
+                return null;
+            }
+        }
+
+        protected override async global::System.Collections.Generic.IAsyncEnumerable<global::Sample.Models.Cat> GetValuesFromPageAsync(global::System.ClientModel.ClientResult page)
+        {
+            foreach (global::Sample.Models.Cat item in ((global::Sample.Models.Page)page).Cats)
+            {
+                yield return item;
+                await global::System.Threading.Tasks.Task.Yield();
+            }
+        }
+    }
+}