[generator] support repeatable directives (ExpediaGroup#1360)

Kotlin 1.6 provides support for repeatable annotations with `RUNTIME` retention. This allows to finally support repeatable directives.

In order to make your directives repeatable, you need to annotate it with `kotlin.annotation.Repeatable` annotation.

```kotlin
@repeatable
@GraphQLDirective
annotation class MyRepeatableDirective(val value: String)
```

Generates the above directive as

```graphql
directive @myRepeatableDirective(value: String!) repeatable on OBJECT | INTERFACE
```

Related Issues:
* resolves ExpediaGroup#590
* depends on ExpediaGroup#1358

Author: Dariusz Kuc

generator/graphql-kotlin-federation/src/main/kotlin/com/expediagroup/graphql/generator/federation/FederatedSchemaGeneratorHooks.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -147,7 +147,7 @@ open class FederatedSchemaGeneratorHooks(private val resolvers: List<FederatedTy
         return originalSchema.allTypesAsList
             .asSequence()
             .filterIsInstance<GraphQLObjectType>()
-            .filter { type -> type.getDirective(KEY_DIRECTIVE_NAME) != null }
+            .filter { type -> type.hasDirective(KEY_DIRECTIVE_NAME) }
             .map { it.name }
             .toSet()
     }

generator/graphql-kotlin-federation/src/main/kotlin/com/expediagroup/graphql/generator/federation/directives/KeyDirective.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,16 +21,13 @@ import graphql.introspection.Introspection.DirectiveLocation
 
 /**
  * ```graphql
- * directive @key(fields: _FieldSet!) on OBJECT | INTERFACE
+ * directive @key(fields: _FieldSet!) repeatable on OBJECT | INTERFACE
  * ```
  *
  * The @key directive is used to indicate a combination of fields that can be used to uniquely identify and fetch an object or interface. Key directive should be specified on the root base type as
  * well as all the corresponding federated (i.e. extended) types. Key fields specified in the directive field set should correspond to a valid field on the underlying GraphQL interface/object.
  * Federated extended types should also instrument all the referenced key fields with @external directive.
  *
- * NOTE: The Federation spec specifies that multiple @key directives can be applied on the field. The GraphQL spec has been recently changed to allow this behavior,
- *   but we are currently blocked and are tracking progress in [this issue](https://github.com/ExpediaGroup/graphql-kotlin/issues/590).
- *
  * Example:
  * Given
  *
@@ -55,6 +52,7 @@ import graphql.introspection.Introspection.DirectiveLocation
  * @see ExtendsDirective
  * @see ExternalDirective
  */
+@Repeatable
 @GraphQLDirective(
     name = KEY_DIRECTIVE_NAME,
     description = KEY_DIRECTIVE_DESCRIPTION,
@@ -70,4 +68,5 @@ internal val KEY_DIRECTIVE_TYPE: graphql.schema.GraphQLDirective = graphql.schem
     .description(KEY_DIRECTIVE_DESCRIPTION)
     .validLocations(DirectiveLocation.OBJECT, DirectiveLocation.INTERFACE)
     .argument(FIELD_SET_ARGUMENT)
+    .repeatable(true)
     .build()

generator/graphql-kotlin-federation/src/main/kotlin/com/expediagroup/graphql/generator/federation/extensions/GraphQLDirectiveContainerExtensions.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,6 @@ import com.expediagroup.graphql.generator.federation.directives.EXTENDS_DIRECTIV
 import com.expediagroup.graphql.generator.federation.directives.KEY_DIRECTIVE_NAME
 import graphql.schema.GraphQLDirectiveContainer
 
-internal fun GraphQLDirectiveContainer.isFederatedType() = this.getDirective(KEY_DIRECTIVE_NAME) != null || isExtendedType()
+internal fun GraphQLDirectiveContainer.isFederatedType() = this.getDirectives(KEY_DIRECTIVE_NAME).isNotEmpty() || isExtendedType()
 
 internal fun GraphQLDirectiveContainer.isExtendedType() = this.getDirective(EXTENDS_DIRECTIVE_NAME) != null

generator/graphql-kotlin-federation/src/main/kotlin/com/expediagroup/graphql/generator/federation/extensions/graphQLSchemaExtensions.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,7 +27,7 @@ internal fun GraphQLSchema.addDirectivesIfNotPresent(directives: List<GraphQLDir
     val newBuilder = GraphQLSchema.newSchema(this)
 
     directives.forEach {
-        if (this.getDirective(it.name) == null) {
+        if (!this.allDirectivesByName.containsKey(it.name)) {
             newBuilder.additionalDirective(it)
         }
     }

generator/graphql-kotlin-federation/src/main/kotlin/com/expediagroup/graphql/generator/federation/validation/FederatedSchemaValidator.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -48,24 +48,24 @@ internal class FederatedSchemaValidator {
     internal fun validateGraphQLType(type: GraphQLType) {
         val unwrappedType = GraphQLTypeUtil.unwrapAll(type)
         if (unwrappedType is GraphQLObjectType && unwrappedType.isFederatedType()) {
-            validate(unwrappedType.name, unwrappedType.fieldDefinitions, unwrappedType.directivesByName)
+            validate(unwrappedType.name, unwrappedType.fieldDefinitions, unwrappedType.allDirectivesByName)
         } else if (unwrappedType is GraphQLInterfaceType && unwrappedType.isFederatedType()) {
-            validate(unwrappedType.name, unwrappedType.fieldDefinitions, unwrappedType.directivesByName)
+            validate(unwrappedType.name, unwrappedType.fieldDefinitions, unwrappedType.allDirectivesByName)
         }
     }
 
-    private fun validate(federatedType: String, fields: List<GraphQLFieldDefinition>, directives: Map<String, GraphQLDirective>) {
+    private fun validate(federatedType: String, fields: List<GraphQLFieldDefinition>, directiveMap: Map<String, List<GraphQLDirective>>) {
         val errors = mutableListOf<String>()
         val fieldMap = fields.associateBy { it.name }
-        val extendedType = directives.containsKey(EXTENDS_DIRECTIVE_NAME)
+        val extendedType = directiveMap.containsKey(EXTENDS_DIRECTIVE_NAME)
 
         // [OK]    @key directive is specified
         // [OK]    @key references valid existing fields
         // [OK]    @key on @extended type references @external fields
         // [ERROR] @key references fields resulting in list
         // [ERROR] @key references fields resulting in union
         // [ERROR] @key references fields resulting in interface
-        errors.addAll(validateDirective(federatedType, KEY_DIRECTIVE_NAME, directives, fieldMap, extendedType))
+        errors.addAll(validateDirective(federatedType, KEY_DIRECTIVE_NAME, directiveMap, fieldMap, extendedType))
 
         for (field in fields) {
             if (field.getDirective(REQUIRES_DIRECTIVE_NAME) != null) {

generator/graphql-kotlin-federation/src/main/kotlin/com/expediagroup/graphql/generator/federation/validation/validateDirective.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,28 +24,30 @@ import graphql.schema.GraphQLFieldDefinition
 internal fun validateDirective(
     validatedType: String,
     targetDirective: String,
-    directives: Map<String, GraphQLDirective>,
+    directiveMap: Map<String, List<GraphQLDirective>>,
     fieldMap: Map<String, GraphQLFieldDefinition>,
     extendedType: Boolean
 ): List<String> {
     val validationErrors = mutableListOf<String>()
-    val directive = directives[targetDirective]
+    val directives = directiveMap[targetDirective]
 
-    if (directive == null) {
+    if (directives == null) {
         validationErrors.add("@$targetDirective directive is missing on federated $validatedType type")
     } else {
-        val fieldSetValue = (directive.getArgument(FIELD_SET_ARGUMENT_NAME)?.argumentValue?.value as? FieldSet)?.value
-        val fieldSet = fieldSetValue?.split(" ")?.filter { it.isNotEmpty() }.orEmpty()
-        if (fieldSet.isEmpty()) {
-            validationErrors.add("@$targetDirective directive on $validatedType is missing field information")
-        } else {
-            // validate directive field set selection
-            val directiveInfo = DirectiveInfo(
-                directiveName = targetDirective,
-                fieldSet = fieldSet.joinToString(" "),
-                typeName = validatedType
-            )
-            validateFieldSelection(directiveInfo, fieldSet.iterator(), fieldMap, extendedType, validationErrors)
+        for (directive in directives) {
+            val fieldSetValue = (directive.getArgument(FIELD_SET_ARGUMENT_NAME)?.argumentValue?.value as? FieldSet)?.value
+            val fieldSet = fieldSetValue?.split(" ")?.filter { it.isNotEmpty() }.orEmpty()
+            if (fieldSet.isEmpty()) {
+                validationErrors.add("@$targetDirective directive on $validatedType is missing field information")
+            } else {
+                // validate directive field set selection
+                val directiveInfo = DirectiveInfo(
+                    directiveName = targetDirective,
+                    fieldSet = fieldSet.joinToString(" "),
+                    typeName = validatedType
+                )
+                validateFieldSelection(directiveInfo, fieldSet.iterator(), fieldMap, extendedType, validationErrors)
+            }
         }
     }
     return validationErrors

generator/graphql-kotlin-federation/src/main/kotlin/com/expediagroup/graphql/generator/federation/validation/validateProvidesDirective.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -40,7 +40,7 @@ internal fun validateProvidesDirective(federatedType: String, field: GraphQLFiel
             validateDirective(
                 "$federatedType.${field.name}",
                 PROVIDES_DIRECTIVE_NAME,
-                field.directivesByName,
+                field.allDirectivesByName,
                 returnTypeFields,
                 true
             )

generator/graphql-kotlin-federation/src/main/kotlin/com/expediagroup/graphql/generator/federation/validation/validateRequiresDirective.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,7 +25,7 @@ import graphql.schema.GraphQLFieldDefinition
 internal fun validateRequiresDirective(validatedType: String, validatedField: GraphQLFieldDefinition, fieldMap: Map<String, GraphQLFieldDefinition>, extendedType: Boolean): List<String> {
     val errors = mutableListOf<String>()
     if (extendedType) {
-        errors.addAll(validateDirective("$validatedType.${validatedField.name}", REQUIRES_DIRECTIVE_NAME, validatedField.directivesByName, fieldMap, extendedType))
+        errors.addAll(validateDirective("$validatedType.${validatedField.name}", REQUIRES_DIRECTIVE_NAME, validatedField.allDirectivesByName, fieldMap, extendedType))
     } else {
         errors.add("base $validatedType type has fields marked with @requires directive, validatedField=${validatedField.name}")
     }

generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/FederatedSchemaGeneratorTest.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -58,7 +58,7 @@ private val FEDERATED_SDL =
     directive @custom on SCHEMA | SCALAR | OBJECT | FIELD_DEFINITION | ARGUMENT_DEFINITION | INTERFACE | UNION | ENUM | ENUM_VALUE | INPUT_OBJECT | INPUT_FIELD_DEFINITION
 
     "Space separated list of primary keys needed to access federated object"
-    directive @key(fields: _FieldSet!) on OBJECT | INTERFACE
+    directive @key(fields: _FieldSet!) repeatable on OBJECT | INTERFACE
 
     "Specifies required input field set from the base type for a resolver"
     directive @requires(fields: _FieldSet!) on FIELD_DEFINITION
@@ -75,18 +75,20 @@ private val FEDERATED_SDL =
         url: String!
       ) on SCALAR
 
-    interface Product @extends @key(fields : "id") {
+    interface Product @extends @key(fields : "id") @key(fields : "upc") {
       id: String! @external
       reviews: [Review!]!
+      upc: String! @external
     }
 
     union _Entity = Book | User
 
-    type Book implements Product @extends @key(fields : "id") {
+    type Book implements Product @extends @key(fields : "id") @key(fields : "upc") {
       author: User! @provides(fields : "name")
       id: String! @external
       reviews: [Review!]!
       shippingCost: String! @requires(fields : "weight")
+      upc: String! @external
       weight: Float! @external
     }
 
@@ -136,7 +138,7 @@ class FederatedSchemaGeneratorTest {
         assertEquals(FEDERATED_SDL, schema.print().trim())
         val productType = schema.getObjectType("Book")
         assertNotNull(productType)
-        assertNotNull(productType.getDirective(KEY_DIRECTIVE_NAME))
+        assertNotNull(productType.hasDirective(KEY_DIRECTIVE_NAME))
 
         val entityUnion = schema.getType(ENTITY_UNION_NAME) as? GraphQLUnionType
         assertNotNull(entityUnion)
@@ -185,7 +187,7 @@ class FederatedSchemaGeneratorTest {
             directive @provides(fields: _FieldSet!) on FIELD_DEFINITION
 
             "Space separated list of primary keys needed to access federated object"
-            directive @key(fields: _FieldSet!) on OBJECT | INTERFACE
+            directive @key(fields: _FieldSet!) repeatable on OBJECT | INTERFACE
 
             "Marks target object as extending part of the federated schema"
             directive @extends on OBJECT | INTERFACE

generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_1/FederatedMissingKey.kt renamed to generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_01/FederatedMissingKey.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.expediagroup.graphql.generator.federation.data.integration.key.failure._1
+package com.expediagroup.graphql.generator.federation.data.integration.key.failure._01
 
 import com.expediagroup.graphql.generator.federation.directives.ExtendsDirective
 import com.expediagroup.graphql.generator.federation.directives.ExternalDirective

generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_2/KeyMissingFieldSelection.kt renamed to generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_02/KeyMissingFieldSelection.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.expediagroup.graphql.generator.federation.data.integration.key.failure._2
+package com.expediagroup.graphql.generator.federation.data.integration.key.failure._02
 
 import com.expediagroup.graphql.generator.federation.directives.FieldSet
 import com.expediagroup.graphql.generator.federation.directives.KeyDirective

generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_3/InvalidKey.kt renamed to generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_03/InvalidKey.kt

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.expediagroup.graphql.generator.federation.data.integration.key.failure._3
+package com.expediagroup.graphql.generator.federation.data.integration.key.failure._03
 
 import com.expediagroup.graphql.generator.federation.directives.FieldSet
 import com.expediagroup.graphql.generator.federation.directives.KeyDirective

generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_4/BaseKeyReferencingExternalFields.kt renamed to generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_04/BaseKeyReferencingExternalFields.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.expediagroup.graphql.generator.federation.data.integration.key.failure._4
+package com.expediagroup.graphql.generator.federation.data.integration.key.failure._04
 
 import com.expediagroup.graphql.generator.federation.directives.ExternalDirective
 import com.expediagroup.graphql.generator.federation.directives.FieldSet

generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_5/ExternalKeyReferencingLocalField.kt renamed to generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_05/ExternalKeyReferencingLocalField.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.expediagroup.graphql.generator.federation.data.integration.key.failure._5
+package com.expediagroup.graphql.generator.federation.data.integration.key.failure._05
 
 import com.expediagroup.graphql.generator.federation.directives.ExtendsDirective
 import com.expediagroup.graphql.generator.federation.directives.FieldSet

generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_6/KeyReferencingList.kt renamed to generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_06/KeyReferencingList.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.expediagroup.graphql.generator.federation.data.integration.key.failure._6
+package com.expediagroup.graphql.generator.federation.data.integration.key.failure._06
 
 import com.expediagroup.graphql.generator.federation.directives.FieldSet
 import com.expediagroup.graphql.generator.federation.directives.KeyDirective

generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_7/KeyReferencingInterface.kt renamed to generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_07/KeyReferencingInterface.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.expediagroup.graphql.generator.federation.data.integration.key.failure._7
+package com.expediagroup.graphql.generator.federation.data.integration.key.failure._07
 
 import com.expediagroup.graphql.generator.federation.directives.FieldSet
 import com.expediagroup.graphql.generator.federation.directives.KeyDirective

generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_8/KeyReferencingUnion.kt renamed to generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/data/integration/key/failure/_08/KeyReferencingUnion.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.expediagroup.graphql.generator.federation.data.integration.key.failure._8
+package com.expediagroup.graphql.generator.federation.data.integration.key.failure._08
 
 import com.expediagroup.graphql.generator.federation.directives.FieldSet
 import com.expediagroup.graphql.generator.federation.directives.KeyDirective