Fix PageInfo Shareable Directive with Apollo Federation

src/All.slnx

@@ -33,6 +33,7 @@
   </Folder>
   <Folder Name="/HotChocolate/ApolloFederation/test/">
     <Project Path="HotChocolate/ApolloFederation/test/ApolloFederation.Tests/HotChocolate.ApolloFederation.Tests.csproj" />
+    <Project Path="HotChocolate/ApolloFederation/test/ApolloFederation.ImplementationFirst/HotChocolate.ApolloFederation.ImplementationFirst.Tests.csproj" />
   </Folder>
   <Folder Name="/HotChocolate/AspNetCore/" />
   <Folder Name="/HotChocolate/AspNetCore/benchmarks/" />

src/HotChocolate/ApolloFederation/HotChocolate.ApolloFederation.slnx

@@ -4,5 +4,6 @@
   </Folder>
   <Folder Name="/test/">
     <Project Path="test/ApolloFederation.Tests/HotChocolate.ApolloFederation.Tests.csproj" />
+    <Project Path="test/ApolloFederation.ImplementationFirst/HotChocolate.ApolloFederation.ImplementationFirst.Tests.csproj" />
   </Folder>
 </Solution>

src/HotChocolate/ApolloFederation/src/ApolloFederation/FederationTypeInterceptor.cs

@@ -117,13 +117,24 @@ public override IEnumerable<TypeReference> RegisterMoreTypes(
             yield return _typeInspector.GetTypeRef(typeof(LinkDirective));
         }
 
-        if (discoveryContexts.Any(t => t.Type is PageInfoType)
+        // The page info fields are made shareable in OnAfterCompleteName for any type
+        // named "PageInfo". That match is by name, so it also covers the page info type
+        // that is inferred from PageConnection<T> (runtime type PageInfo) and not just the
+        // built-in PageInfoType. We therefore have to register the shareable directive for
+        // any discovered page info object type, otherwise the directive cannot be resolved
+        // when the fields are completed.
+        if (discoveryContexts.Any(t => IsPageInfoType(t.Type))
             && discoveryContexts.All(t => t.Type is not DirectiveType<ShareableDirective>))
         {
             yield return _typeInspector.GetTypeRef(typeof(ShareableDirective));
         }
     }
 
+    private static bool IsPageInfoType(TypeSystemObject type)
+        => type is PageInfoType
+            || (type is IRuntimeTypeProvider { RuntimeType: { } runtimeType }
+                && typeof(IPageInfo).IsAssignableFrom(runtimeType));
+
     public override void OnBeforeCompleteName(
         ITypeCompletionContext completionContext,
         TypeSystemConfiguration configuration)

src/HotChocolate/ApolloFederation/test/ApolloFederation.ImplementationFirst/Employee.cs

@@ -0,0 +1,8 @@
+namespace HotChocolate.ApolloFederation;
+
+public sealed class Employee
+{
+    public int EmpId { get; set; }
+
+    public string Name { get; set; } = default!;
+}

src/HotChocolate/ApolloFederation/test/ApolloFederation.ImplementationFirst/EmployeeQuery.cs

@@ -0,0 +1,16 @@
+using GreenDonut.Data;
+using HotChocolate.Types;
+using HotChocolate.Types.Pagination;
+
+namespace HotChocolate.ApolloFederation;
+
+[QueryType]
+public static partial class EmployeeQuery
+{
+    // Reproduces https://github.com/ChilliCream/graphql-platform/issues/9798:
+    // a source-generated connection field returning PageConnection<T> combined
+    // with Apollo Federation must not crash schema creation.
+    [UseConnection]
+    public static PageConnection<Employee> GetEmployeeByPageTest(PagingArguments args)
+        => new(Page<Employee>.Empty);
+}

src/HotChocolate/ApolloFederation/test/ApolloFederation.ImplementationFirst/HotChocolate.ApolloFederation.ImplementationFirst.Tests.csproj

@@ -0,0 +1,24 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <AssemblyName>HotChocolate.ApolloFederation.ImplementationFirst.Tests</AssemblyName>
+    <RootNamespace>HotChocolate.ApolloFederation</RootNamespace>
+    <InterceptorsPreviewNamespaces>$(InterceptorsPreviewNamespaces);HotChocolate.Execution.Generated</InterceptorsPreviewNamespaces>
+    <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
+    <CompilerGeneratedFilesOutputPath>.generated</CompilerGeneratedFilesOutputPath>
+    <!--Required since otherwise the XML docs won't be inferred by the source generator.-->
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\ApolloFederation\HotChocolate.ApolloFederation.csproj" />
+    <ProjectReference Include="..\..\..\Core\src\Types.Analyzers\HotChocolate.Types.Analyzers.csproj" OutputItemType="Analyzer" />
+    <ProjectReference Include="..\..\..\Data\src\Data\HotChocolate.Data.csproj" />
+    <ProjectReference Include="..\..\..\..\GreenDonut\src\GreenDonut.Data\GreenDonut.Data.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Compile Remove="$(CompilerGeneratedFilesOutputPath)/**/*.cs" />
+  </ItemGroup>
+
+</Project>

src/HotChocolate/ApolloFederation/test/ApolloFederation.ImplementationFirst/ModuleInfo.cs

@@ -0,0 +1,3 @@
+using HotChocolate;
+
+[assembly: Module("ImplementationFirstTypes")]

src/HotChocolate/ApolloFederation/test/ApolloFederation.ImplementationFirst/PageConnectionCompositeSchemaTests.cs

@@ -0,0 +1,27 @@
+using HotChocolate.Execution;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace HotChocolate.ApolloFederation;
+
+// Counterpart to PageConnectionFederationTests: the composite schema path also makes
+// connections and page info shareable (AddSourceSchemaDefaults turns on
+// ApplyShareableToConnections, ApplyShareableToPageInfo and ApplyShareableToNodeFields).
+// Unlike the Apollo Federation interceptor, every composite site registers the Shareable
+// directive type before applying it, so building the schema must not crash.
+public class PageConnectionCompositeSchemaTests
+{
+    [Fact]
+    public async Task PageConnection_Field_With_CompositeSourceSchema_Builds_Schema()
+    {
+        // arrange & act
+        var schema = await new ServiceCollection()
+            .AddGraphQL()
+            .AddSourceSchemaDefaults()
+            .AddImplementationFirstTypes()
+            .AddPagingArguments()
+            .BuildSchemaAsync();
+
+        // assert
+        schema.MatchSnapshot();
+    }
+}

src/HotChocolate/ApolloFederation/test/ApolloFederation.ImplementationFirst/PageConnectionFederationTests.cs

@@ -0,0 +1,22 @@
+using HotChocolate.Execution;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace HotChocolate.ApolloFederation;
+
+public class PageConnectionFederationTests
+{
+    [Fact]
+    public async Task PageConnection_Field_With_ApolloFederation_Builds_Schema()
+    {
+        // arrange & act
+        var schema = await new ServiceCollection()
+            .AddGraphQL()
+            .AddApolloFederation()
+            .AddImplementationFirstTypes()
+            .AddPagingArguments()
+            .BuildSchemaAsync();
+
+        // assert
+        schema.MatchSnapshot();
+    }
+}

src/HotChocolate/ApolloFederation/test/ApolloFederation.ImplementationFirst/__snapshots__/PageConnectionCompositeSchemaTests.PageConnection_Field_With_CompositeSourceSchema_Builds_Schema.graphql

@@ -0,0 +1,82 @@
+schema {
+  query: Query
+}
+
+type Query {
+  employeeByPageTest(
+    "Returns the first _n_ elements from the list."
+    first: Int
+    "Returns the elements in the list that come after the specified cursor."
+    after: String
+    "Returns the last _n_ elements from the list."
+    last: Int
+    "Returns the elements in the list that come before the specified cursor."
+    before: String
+  ): EmployeeConnection!
+}
+
+type Employee {
+  empId: Int!
+  name: String!
+}
+
+"A connection to a list of items."
+type EmployeeConnection @shareable {
+  "A list of edges."
+  edges: [EmployeeEdge!]
+  "A flattened list of the nodes"
+  nodes: [Employee!]
+  "Information to aid in pagination."
+  pageInfo: PageInfo!
+  "Identifies the total count of items in the connection."
+  totalCount: Int!
+}
+
+type EmployeeEdge @shareable {
+  "The item at the end of the edge."
+  node: Employee!
+  "A cursor for use in pagination."
+  cursor: String!
+}
+
+"A cursor that points to a specific page."
+type PageCursor @shareable {
+  "The page number."
+  page: Int!
+  "The cursor."
+  cursor: String!
+}
+
+"Information about pagination in a connection."
+type PageInfo @shareable {
+  "Indicates whether more edges exist following the set defined by the clients arguments."
+  hasNextPage: Boolean!
+  "Indicates whether more edges exist prior the set defined by the clients arguments."
+  hasPreviousPage: Boolean!
+  "When paginating backwards, the cursor to continue."
+  startCursor: String
+  "When paginating forwards, the cursor to continue."
+  endCursor: String
+  "A list of cursors to continue paginating forwards."
+  forwardCursors: [PageCursor!]!
+  "A list of cursors to continue paginating backwards."
+  backwardCursors: [PageCursor!]!
+}
+
+"""
+By default, only a single source schema is allowed to contribute
+a particular field to an object type.
+
+
+This prevents source schemas from inadvertently defining similarly named
+fields that are not semantically equivalent.
+
+
+Fields must be explicitly marked as @shareable to allow multiple source
+schemas to define them, ensuring that the decision to serve a field from
+more than one source schema is intentional and coordinated.
+
+
+directive @shareable repeatable on OBJECT | FIELD_DEFINITION
+"""
+directive @shareable repeatable on OBJECT | FIELD_DEFINITION

src/HotChocolate/ApolloFederation/test/ApolloFederation.ImplementationFirst/__snapshots__/PageConnectionFederationTests.PageConnection_Field_With_ApolloFederation_Builds_Schema.graphql

@@ -0,0 +1,91 @@
+schema
+  @link(
+    url: "https://specs.apollo.dev/federation/v2.6"
+    import: ["@shareable", "@tag", "FieldSet"]
+  ) {
+  query: Query
+}
+
+type Query {
+  employeeByPageTest(
+    "Returns the first _n_ elements from the list."
+    first: Int
+    "Returns the elements in the list that come after the specified cursor."
+    after: String
+    "Returns the last _n_ elements from the list."
+    last: Int
+    "Returns the elements in the list that come before the specified cursor."
+    before: String
+  ): EmployeeConnection!
+  _service: _Service!
+}
+
+"This type provides a field named sdl: String! which exposes the SDL of the service's schema. This SDL (schema definition language) is a printed version of the service's schema including the annotations of federation directives. This SDL does not include the additions of the federation spec."
+type _Service {
+  sdl: String!
+}
+
+type Employee {
+  empId: Int!
+  name: String!
+}
+
+"A connection to a list of items."
+type EmployeeConnection {
+  "A list of edges."
+  edges: [EmployeeEdge!]
+  "A flattened list of the nodes"
+  nodes: [Employee!]
+  "Information to aid in pagination."
+  pageInfo: PageInfo!
+  "Identifies the total count of items in the connection."
+  totalCount: Int!
+}
+
+type EmployeeEdge {
+  "The item at the end of the edge."
+  node: Employee!
+  "A cursor for use in pagination."
+  cursor: String!
+}
+
+"A cursor that points to a specific page."
+type PageCursor {
+  "The page number."
+  page: Int!
+  "The cursor."
+  cursor: String!
+}
+
+"Information about pagination in a connection."
+type PageInfo {
+  "Indicates whether more edges exist following the set defined by the clients arguments."
+  hasNextPage: Boolean! @shareable
+  "Indicates whether more edges exist prior the set defined by the clients arguments."
+  hasPreviousPage: Boolean! @shareable
+  "When paginating backwards, the cursor to continue."
+  startCursor: String @shareable
+  "When paginating forwards, the cursor to continue."
+  endCursor: String @shareable
+  "A list of cursors to continue paginating forwards."
+  forwardCursors: [PageCursor!]! @shareable
+  "A list of cursors to continue paginating backwards."
+  backwardCursors: [PageCursor!]! @shareable
+}
+
+"The _Any scalar is used to pass representations of entities from external services into the root _entities field for execution. Validation of the _Any scalar is done by matching the __typename and @external fields defined in the schema."
+scalar _Any
+
+"Scalar representing a set of fields."
+scalar FieldSet
+
+"Links definitions within the document to external schemas."
+directive @link(
+  "Gets imported specification url."
+  url: String!
+  "Gets optional list of imported element names."
+  import: [String!]
+) repeatable on SCHEMA
+
+"Indicates that given object and/or field can be resolved by multiple subgraphs."
+directive @shareable repeatable on OBJECT | FIELD_DEFINITION