Call hooks for return type on properties (#1112)

Co-authored-by: Shane Myrick <[email protected]>

Author: smyrick

examples/server/spring-server/src/main/kotlin/com/expediagroup/graphql/examples/server/spring/model/DataLoaderQueryModel.kt

@@ -21,8 +21,12 @@ import com.expediagroup.graphql.generator.annotations.GraphQLIgnore
 
 data class Employee(
     val name: String,
+
     @GraphQLIgnore
-    val companyId: Int
+    val companyId: Int,
+
+    @GraphQLDescription("A list of unique skills")
+    val skills: Set<String> = emptySet()
 ) {
     @GraphQLDescription("This value will be populated by a custom data fetcher using data loaders")
     lateinit var company: Company

examples/server/spring-server/src/main/kotlin/com/expediagroup/graphql/examples/server/spring/query/DataLoaderQuery.kt

@@ -33,8 +33,8 @@ import java.util.concurrent.CompletableFuture
 @Component
 class DataLoaderQuery : Query {
     private val employees = listOf(
-        Employee(name = "Mike", companyId = 1),
-        Employee(name = "John", companyId = 1),
+        Employee(name = "Mike", companyId = 1, skills = setOf("sales", "sales")),
+        Employee(name = "John", companyId = 1, skills = setOf("management")),
         Employee(name = "Steve", companyId = 2)
     )
 

examples/server/spring-server/src/main/kotlin/com/expediagroup/graphql/examples/server/spring/query/SimpleQuery.kt

@@ -84,5 +84,6 @@ class SimpleQuery : Query {
         Selection.TWO -> "You chose the second one"
     }
 
-    fun setList(): Set<String> = setOf("one", "one", "two")
+    @GraphQLDescription("Set exposed as a function")
+    fun setList(): Set<Int> = setOf(1, 1, 2, 3)
 }

generator/graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/hooks/SchemaGeneratorHooks.kt

@@ -68,14 +68,14 @@ interface SchemaGeneratorHooks {
     fun willAddGraphQLTypeToSchema(type: KType, generatedType: GraphQLType): GraphQLType = generatedType
 
     /**
-     * Called before resolving a KType to the GraphQL type.
-     * This allows for a custom resolver on how to extract wrapped values, like in a CompletableFuture.
+     * Called before resolving a return type to the GraphQL type.
+     * This allows for changes in the supported return types or unwrapping of specific classes.
      */
     fun willResolveMonad(type: KType): KType = type
 
     /**
-     * Called before resolving a KType to the input GraphQL type.
-     * This allows resolvers for custom deserialization logic of wrapped input values, like in an Optional.
+     * Called before resolving an input type to the input GraphQL type.
+     * This allows for changes in the supported input values and unwrapping of custom types, like in an Optional.
      */
     fun willResolveInputMonad(type: KType): KType = type
 

generator/graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/internal/types/generateProperty.kt

@@ -31,7 +31,8 @@ import kotlin.reflect.KClass
 import kotlin.reflect.KProperty
 
 internal fun generateProperty(generator: SchemaGenerator, prop: KProperty<*>, parentClass: KClass<*>): GraphQLFieldDefinition {
-    val propertyType = generateGraphQLType(generator, type = prop.returnType)
+    val typeFromHooks = generator.config.hooks.willResolveMonad(prop.returnType)
+    val propertyType = generateGraphQLType(generator, type = typeFromHooks)
         .safeCast<GraphQLOutputType>()
 
     val propertyName = prop.getPropertyName(parentClass)

generator/graphql-kotlin-schema-generator/src/test/kotlin/com/expediagroup/graphql/generator/internal/types/GeneratePropertyTest.kt

@@ -25,6 +25,7 @@ import com.expediagroup.graphql.generator.directives.KotlinDirectiveWiringFactor
 import com.expediagroup.graphql.generator.directives.KotlinSchemaDirectiveWiring
 import com.expediagroup.graphql.generator.execution.KotlinDataFetcherFactoryProvider
 import com.expediagroup.graphql.generator.execution.PropertyDataFetcher
+import com.expediagroup.graphql.generator.extensions.deepName
 import com.expediagroup.graphql.generator.hooks.SchemaGeneratorHooks
 import com.expediagroup.graphql.generator.internal.extensions.getSimpleName
 import com.expediagroup.graphql.generator.scalars.ID
@@ -41,6 +42,8 @@ import io.mockk.every
 import io.mockk.mockk
 import io.mockk.spyk
 import org.junit.jupiter.api.Test
+import kotlin.reflect.KType
+import kotlin.reflect.full.createType
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
 import kotlin.test.assertNotNull
@@ -53,7 +56,7 @@ class GeneratePropertyTest : TypeTestHelper() {
     @GraphQLDirective(locations = [Introspection.DirectiveLocation.FIELD_DEFINITION])
     internal annotation class PropertyDirective(val arg: String)
 
-    private class ClassWithProperties {
+    class ClassWithProperties {
         @GraphQLDescription("It's not a lie")
         @PropertyDirective("trust me")
         val cake: String = "chocolate"
@@ -68,6 +71,8 @@ class GeneratePropertyTest : TypeTestHelper() {
 
         @GraphQLName("pie")
         val renameMe: String = "apple"
+
+        val setList: Set<Int> = setOf(1, 1, 2, 3)
     }
 
     private data class DataClassWithProperties(
@@ -227,4 +232,25 @@ class GeneratePropertyTest : TypeTestHelper() {
         assertEquals(expected = mockDataFetcher, actual = targetDataFetcher)
         localGenerator.close()
     }
+
+    @Test
+    fun `hooks are called on properties`() {
+        val hooks: SchemaGeneratorHooks = object : SchemaGeneratorHooks {
+            override fun willResolveMonad(type: KType): KType = when (type.classifier) {
+                Set::class -> List::class.createType(type.arguments)
+                else -> type
+            }
+        }
+
+        val localConfig = SchemaGeneratorConfig(
+            supportedPackages = emptyList(),
+            hooks = hooks
+        )
+        val localGenerator = SchemaGenerator(localConfig)
+
+        val prop = ClassWithProperties::setList
+        val result = generateProperty(localGenerator, prop, ClassWithProperties::class)
+
+        assertEquals("[Int!]!", result.type.deepName)
+    }
 }