Add Apollo Federation Composition

[michaelstaib]

No description provided.

[Copilot]

Pull request overview

This PR adds first-class Apollo Federation v2 subgraph composition support to Fusion by transforming federation SDL into Composite Schema Spec source schemas, stamping each source schema with a connector kind, and updating execution-time configuration parsing/client creation to use that connector metadata.

Changes:

• Introduces an Apollo Federation transformation pipeline in Fusion.Composition (remove federation infrastructure, generate lookup fields, rewrite keys/requires, stamp @fusion__connector(kind: "Apollo")).
• Lifts connector kind into the merged execution schema (fusion__Schema enum values) and exposes FusionSchemaDefinition.GetSourceSchemaConnectorKind(...).
• Refactors execution configuration parsing to claim whole source schemas (not per-transport), supports multiple configurations per schema, and passes the composed schema into client factories.

Reviewed changes

Copilot reviewed 63 out of 76 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/HotChocolate/Fusion/test/Fusion.Execution.Tests/Execution/Types/FusionSchemaDefinitionConnectorKindTests.cs	Adds tests for GetSourceSchemaConnectorKind behavior (Apollo vs absent/GraphQL/unknown).
src/HotChocolate/Fusion/test/Fusion.Execution.Tests/Configuration/ParsersTests.cs	Updates execution configuration parsing tests to new “claim schema” parser model and adds legacy Apollo settings mismatch test.
src/HotChocolate/Fusion/test/Fusion.Connectors.ApolloFederation.Tests/snapshots/SchemaTransformationIntegrationTests.Transform_FederationSubgraph_Should_ProduceValidSourceSchema.graphql	Updates snapshot to include @fusion__connector(kind: "Apollo") and directive definition.
src/HotChocolate/Fusion/test/Fusion.Connectors.ApolloFederation.Tests/SchemaTransformationIntegrationTests.cs	Renames/aligns test to validate transformed source schema SDL rather than “composite”.
src/HotChocolate/Fusion/test/Fusion.Connectors.ApolloFederation.Tests/Configuration/ParsersTests.cs	Updates Apollo connector parser tests to claim by connector kind and use new parser signature/output.
src/HotChocolate/Fusion/test/Fusion.Connectors.ApolloFederation.Tests/Configuration/LookupArgumentPathMapperTests.cs	Adds unit tests for mapping FSM selection nodes to representation field paths.
src/HotChocolate/Fusion/test/Fusion.Connectors.ApolloFederation.Tests/Configuration/ApolloFederationCompletionTests.cs	Adds tests ensuring Apollo config completion projects lookups/requires and rewriter binding behavior.
src/HotChocolate/Fusion/test/Fusion.Connectors.ApolloFederation.Tests/ApolloFederationConnectorTests.cs	Updates configuration constructor expectations after moving lookup/require projection to completion.
src/HotChocolate/Fusion/test/Fusion.Connectors.ApolloFederation.Compliance.Tests/Infrastructure/FusionGatewayBuilder.cs	Stops emitting legacy extensions.apolloFederation settings and uses transformed source schema SDL.
src/HotChocolate/Fusion/test/Fusion.Connectors.ApolloFederation.Compliance.Tests/HotChocolate.Fusion.Connectors.ApolloFederation.Compliance.Tests.csproj	Removes dependency on the deleted Fusion.Composition.ApolloFederation project.
src/HotChocolate/Fusion/test/Fusion.Composition.Tests/snapshots/SourceSchemaMergerTests.Merge_FourNamedSchemas_AddsFusionDefinitions.graphql	Updates snapshot to include fusion__connector directive definition on enum values.
src/HotChocolate/Fusion/test/Fusion.Composition.Tests/SourceSchemaMerger.ConnectorDirective.Tests.cs	Adds tests for lifting connector kind onto fusion__Schema enum values.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/snapshots/FederationSchemaTransformerTests.Transform_SimpleEntity.md	Updates federation transformer snapshot to include connector stamping.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/snapshots/FederationSchemaTransformerTests.Transform_RequiresDirective.md	Updates snapshot to include connector stamping.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/snapshots/FederationSchemaTransformerTests.Transform_ProvidesDirective.md	Updates snapshot to include connector stamping.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/snapshots/FederationSchemaTransformerTests.Transform_NonResolvableKey.md	Updates snapshot to include connector stamping.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/snapshots/FederationSchemaTransformerTests.Transform_NonResolvableAndResolvableKeys.md	Updates snapshot to include connector stamping.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/snapshots/FederationSchemaTransformerTests.Transform_NestedObjectKey.md	Updates snapshot to include connector stamping.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/snapshots/FederationSchemaTransformerTests.Transform_NestedListKey.md	Updates snapshot to include connector stamping.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/snapshots/FederationSchemaTransformerTests.Transform_MultipleKeys.md	Updates snapshot to include connector stamping.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/snapshots/FederationSchemaTransformerTests.Transform_KeyResolvableArgument.md	Updates snapshot to include connector stamping.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/snapshots/FederationSchemaTransformerTests.Transform_FullIntegration.md	Updates snapshot to include connector stamping.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/snapshots/FederationSchemaTransformerTests.Transform_ExternalDirective.md	Updates snapshot to include connector stamping.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/snapshots/FederationSchemaTransformerTests.Transform_DeeplyNestedListKey.md	Updates snapshot to include connector stamping.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/snapshots/FederationSchemaTransformerTests.Transform_CompositeKey.md	Updates snapshot to include connector stamping.
src/HotChocolate/Fusion/test/Fusion.Composition.ApolloFederation.Tests/HotChocolate.Fusion.Composition.ApolloFederation.Tests.csproj	Switches tests to reference Fusion.Composition after deleting separate federation composition project.
src/HotChocolate/Fusion/src/Fusion.Execution/Execution/FusionRequestExecutorManager.cs	Moves client configuration creation into a schema interceptor and changes how config is attached to schema features.
src/HotChocolate/Fusion/src/Fusion.Execution/Execution/FusionOptions.cs	Sets EnableSemanticIntrospection default initializer.
src/HotChocolate/Fusion/src/Fusion.Execution/Execution/Clients/SourceSchemaClientFactory.cs	Updates client factory API to accept the composed FusionSchemaDefinition.
src/HotChocolate/Fusion/src/Fusion.Execution/Execution/Clients/ISourceSchemaClientFactory.cs	Updates factory interface to accept the composed FusionSchemaDefinition.
src/HotChocolate/Fusion/src/Fusion.Execution/Execution/Clients/HttpSourceSchemaClientFactory.cs	Updates HTTP client factory override signature to accept schema.
src/HotChocolate/Fusion/src/Fusion.Execution/Execution/Clients/DefaultSourceSchemaClientScope.cs	Passes schema through to factories when creating clients.
src/HotChocolate/Fusion/src/Fusion.Execution/Configuration/Parsers/DefaultGraphQLClientConfigurationParser.cs	Renames built-in parser and adapts it to new “claim schema” parsing contract.
src/HotChocolate/Fusion/src/Fusion.Execution/Configuration/ISourceSchemaClientConfigurationParser.cs	Changes parser API to claim a source schema and emit multiple configs.
src/HotChocolate/Fusion/src/Fusion.Execution.Types/Metadata/SourceSchemaInfo.cs	Extends SourceSchemaInfo to include ConnectorKind.
src/HotChocolate/Fusion/src/Fusion.Execution.Types/HotChocolate.Fusion.Execution.Types.csproj	Adds IVT to the Apollo Federation connector assembly.
src/HotChocolate/Fusion/src/Fusion.Execution.Types/FusionSchemaDefinition.cs	Stores connector kind per source schema and exposes GetSourceSchemaConnectorKind.
src/HotChocolate/Fusion/src/Fusion.Execution.Types/FusionBuiltIns.cs	Adds built-in name constant for fusion__connector.
src/HotChocolate/Fusion/src/Fusion.Execution.Types/Completion/CompositeSchemaBuilder.cs	Captures connector kind when building the source schema lookup.
src/HotChocolate/Fusion/src/Fusion.Connectors.InMemory/InMemorySourceSchemaClientFactory.cs	Updates in-memory client factory override signature to accept schema.
src/HotChocolate/Fusion/src/Fusion.Connectors.ApolloFederation/LookupFieldInfo.cs	Updates docs to reflect lookups now refer to the source schema.
src/HotChocolate/Fusion/src/Fusion.Connectors.ApolloFederation/LookupArgumentPathMapper.cs	Adds FSM selection-node → representation path mapping helper.
src/HotChocolate/Fusion/src/Fusion.Connectors.ApolloFederation/HotChocolate.Fusion.Connectors.ApolloFederation.csproj	Removes dependency on deleted federation composition project.
src/HotChocolate/Fusion/src/Fusion.Connectors.ApolloFederation/DependencyInjection/ApolloFederationFusionGatewayBuilderExtensions.cs	Updates DI extension docs for new connector-kind based behavior.
src/HotChocolate/Fusion/src/Fusion.Connectors.ApolloFederation/ApolloFederationSourceSchemaClientFactory.cs	Uses completed configuration’s rewriter and updates signature to accept schema.
src/HotChocolate/Fusion/src/Fusion.Connectors.ApolloFederation/ApolloFederationSourceSchemaClientConfiguration.cs	Moves federation lookup/require projection into schema completion and exposes per-schema rewriter.
src/HotChocolate/Fusion/src/Fusion.Connectors.ApolloFederation/ApolloFederationClientConfigurationParser.cs	Claims schema based on connector kind and parses http transport block.
src/HotChocolate/Fusion/src/Fusion.Composition/WellKnownDirectiveNames.cs	Adds fusion__connector directive name constant.
src/HotChocolate/Fusion/src/Fusion.Composition/WellKnownArgumentNames.cs	Adds kind argument name constant.
src/HotChocolate/Fusion/src/Fusion.Composition/SourceSchemaPreprocessor.cs	Runs federation subgraph preprocessing (transform + stamping) when federation is detected.
src/HotChocolate/Fusion/src/Fusion.Composition/SourceSchemaMerger.cs	Adds fusion__connector directive definition and lifts connector kind onto schema enum values.
src/HotChocolate/Fusion/src/Fusion.Composition/Properties/CompositionResources.resx	Adds localized strings for connector directive descriptions.
src/HotChocolate/Fusion/src/Fusion.Composition/Properties/CompositionResources.Designer.cs	Adds generated accessors for new connector directive resource strings.
src/HotChocolate/Fusion/src/Fusion.Composition/Logging/LogEntryCodes.cs	Adds log entry codes for federation validation errors.
src/HotChocolate/Fusion/src/Fusion.Composition/HotChocolate.Fusion.Composition.csproj	Embeds federation resources and adds IVT for federation composition tests.
src/HotChocolate/Fusion/src/Fusion.Composition/FusionBuiltIns.cs	Registers connector directive as a source-schema directive.
src/HotChocolate/Fusion/src/Fusion.Composition/Definitions/FusionConnectorMutableDirectiveDefinition.cs	Adds enum-value @fusion__connector(kind:) directive definition for execution schema.
src/HotChocolate/Fusion/src/Fusion.Composition/Definitions/ConnectorMutableDirectiveDefinition.cs	Adds schema-level @fusion__connector(kind:) directive definition for source schemas.
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/TransformRequiresToRequire.cs	Implements federation @requires → composite-spec @require argument rewrite.
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/StampConnectorKind.cs	Stamps @fusion__connector(kind: "Apollo") onto transformed federation source schemas.
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/RewriteKeyDirectives.cs	Strips resolvable: from @key directives.
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/RemoveFederationInfrastructure.cs	Removes federation infra types/fields/directives from source schema.
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/RemoveExternalFields.cs	Removes @external fields from types.
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/Properties/FederationResources.resx	Adds federation validation/parse error resource strings.
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/Properties/FederationResources.Designer.cs	Adds generated accessors for federation resource strings.
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/GenerateLookupFields.cs	Generates @lookup fields + @is mapping for resolvable federation keys.
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/FederationTypeNames.cs	Adds federation type name constants.
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/FederationSchemaTransformer.cs	Adds federation-schema detection and routes validation through CompositionLog.
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/FederationSchemaAnalyzer.cs	Implements federation v2 checks and logs composition errors (v1/unsupported directives).
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/FederationFieldNames.cs	Adds federation field name constants.
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/FederationDirectiveNames.cs	Adds federation directive name constants.
src/HotChocolate/Fusion/src/Fusion.Composition/ApolloFederation/EntityKeyInfo.cs	Adds a small model for key directive info.
src/HotChocolate/Fusion/src/Fusion.Composition.ApolloFederation/HotChocolate.Fusion.Composition.ApolloFederation.csproj	Deletes the standalone federation composition project.
src/HotChocolate/Fusion/HotChocolate.Fusion.slnx	Removes deleted federation composition project from solution.
src/All.slnx	Removes deleted federation composition project from umbrella solution.
.gitignore	Adds .work/ to ignored paths.

Files not reviewed (1)

• src/HotChocolate/Fusion/src/Fusion.Composition/Properties/CompositionResources.Designer.cs: Language not supported

Comments suppressed due to low confidence (2)

src/HotChocolate/Fusion/src/Fusion.Execution/Configuration/Parsers/DefaultGraphQLClientConfigurationParser.cs:33

• DefaultGraphQLClientConfigurationParser currently claims any source schema that has transports.http, even when the composed schema declares a non-GraphQL connector kind (e.g. Apollo). This can silently fall back to the default GraphQL client if the intended connector/parser wasn’t registered; consider checking schema.GetSourceSchemaConnectorKind(sourceSchema.Name) and returning false when it’s a non-null/non-GraphQL kind so misconfiguration surfaces as "No parser claimed source schema ...".
  src/HotChocolate/Fusion/src/Fusion.Execution/Configuration/Parsers/DefaultGraphQLClientConfigurationParser.cs:29
• The new execution test expects the default parser to fail loudly when a source schema contains legacy extensions.apolloFederation settings but the composed schema isn’t stamped with @fusion__connector(kind: "Apollo"). TryParse currently ignores the extensions block entirely and will happily claim the schema via transports.http; add an explicit check for extensions.apolloFederation here and throw an InvalidOperationException with a migration hint (as asserted by the test).

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