feat: add dataFetcherResult option to return both errors and partial data

src/config/schema.ts

@@ -121,7 +121,8 @@ export const configSchema = object({
    *
    * Type names can be optionally passed with the classMethods config to generate the interface with `suspend` functions or
    * `java.util.concurrent.CompletableFuture` functions. Pass `nullableDataFetchingEnvironment: true` to make the
-   * `DataFetchingEnvironment` argument nullable in each resolver function for that class.
+   * `DataFetchingEnvironment` argument nullable in each resolver function for that class. Pass `dataFetcherResult: true`
+   * to make functions return `DataFetcherResult` to hold both data and errors.
    * @example
    * [
    *   {
@@ -138,6 +139,10 @@ export const configSchema = object({
    *   {
    *     typeName: "MyTypeWithNullableDataFetchingEnvironment",
    *     nullableDataFetchingEnvironment: true,
+   *   },
+   *   {
+   *     typeName: "MyTypeWithPartialData",
+   *     dataFetcherResult: true,
    *   }
    * ]
    * @link https://opensource.expediagroup.com/graphql-kotlin-codegen/docs/recommended-usage
@@ -150,6 +155,7 @@ export const configSchema = object({
           union([literal("SUSPEND"), literal("COMPLETABLE_FUTURE")]),
         ),
         nullableDataFetchingEnvironment: optional(boolean()),
+        dataFetcherResult: optional(boolean()),
       }),
     ),
   ),

src/definitions/field.ts

@@ -183,8 +183,13 @@ function buildField(
   );
   const isCompletableFuture =
     typeInResolverInterfacesConfig?.classMethods === "COMPLETABLE_FUTURE";
-  const completableFutureDefinition = `java.util.concurrent.CompletableFuture<${typeMetadata.typeName}${typeMetadata.isNullable ? "?" : ""}> = ${defaultImplementation}`;
-  const defaultDefinition = `${typeMetadata.typeName}${defaultDefinitionValue}`;
+  let typeDefinition = `${typeMetadata.typeName}${typeMetadata.isNullable ? "?" : ""}`;
+  let defaultDefinition = `${typeMetadata.typeName}${defaultDefinitionValue}`;
+  if (typeInResolverInterfacesConfig?.dataFetcherResult) {
+    typeDefinition = `graphql.execution.DataFetcherResult<${typeDefinition}>`;
+    defaultDefinition = `${typeDefinition} = ${defaultImplementation}`;
+  }
+  const completableFutureDefinition = `java.util.concurrent.CompletableFuture<${typeDefinition}> = ${defaultImplementation}`;
   return indent(
     `${functionDefinition}: ${isCompletableFuture ? completableFutureDefinition : defaultDefinition}`,
     2,

test/unit/should_honor_dataFetcherResult_config_completable_future/codegen.config.ts

@@ -0,0 +1,11 @@
+import { GraphQLKotlinCodegenConfig } from "../../../src/plugin";
+
+export default {
+  resolverInterfaces: [
+    {
+      typeName: "DataFetcherResultCompletableFutureType",
+      classMethods: "COMPLETABLE_FUTURE",
+      dataFetcherResult: true,
+    },
+  ],
+} satisfies GraphQLKotlinCodegenConfig;

test/unit/should_honor_dataFetcherResult_config_completable_future/expected.kt

@@ -0,0 +1,17 @@
+package com.kotlin.generated
+
+import com.expediagroup.graphql.generator.annotations.*
+
+@GraphQLValidObjectLocations(locations = [GraphQLValidObjectLocations.Locations.OBJECT])
+open class DataFetcherResultCompletableFutureType {
+    open fun stringField1(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): java.util.concurrent.CompletableFuture<graphql.execution.DataFetcherResult<String?>> = throw NotImplementedError("DataFetcherResultCompletableFutureType.stringField1 must be implemented.")
+    open fun stringField2(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): java.util.concurrent.CompletableFuture<graphql.execution.DataFetcherResult<String>> = throw NotImplementedError("DataFetcherResultCompletableFutureType.stringField2 must be implemented.")
+    open fun booleanField1(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): java.util.concurrent.CompletableFuture<graphql.execution.DataFetcherResult<Boolean?>> = throw NotImplementedError("DataFetcherResultCompletableFutureType.booleanField1 must be implemented.")
+    open fun booleanField2(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): java.util.concurrent.CompletableFuture<graphql.execution.DataFetcherResult<Boolean>> = throw NotImplementedError("DataFetcherResultCompletableFutureType.booleanField2 must be implemented.")
+    open fun integerField1(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): java.util.concurrent.CompletableFuture<graphql.execution.DataFetcherResult<Int?>> = throw NotImplementedError("DataFetcherResultCompletableFutureType.integerField1 must be implemented.")
+    open fun integerField2(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): java.util.concurrent.CompletableFuture<graphql.execution.DataFetcherResult<Int>> = throw NotImplementedError("DataFetcherResultCompletableFutureType.integerField2 must be implemented.")
+    open fun listField(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): java.util.concurrent.CompletableFuture<graphql.execution.DataFetcherResult<List<String>>> = throw NotImplementedError("DataFetcherResultCompletableFutureType.listField must be implemented.")
+    open fun listField2(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): java.util.concurrent.CompletableFuture<graphql.execution.DataFetcherResult<List<String?>>> = throw NotImplementedError("DataFetcherResultCompletableFutureType.listField2 must be implemented.")
+    open fun listField3(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): java.util.concurrent.CompletableFuture<graphql.execution.DataFetcherResult<List<String>?>> = throw NotImplementedError("DataFetcherResultCompletableFutureType.listField3 must be implemented.")
+    open fun listField4(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): java.util.concurrent.CompletableFuture<graphql.execution.DataFetcherResult<List<String?>?>> = throw NotImplementedError("DataFetcherResultCompletableFutureType.listField4 must be implemented.")
+}

test/unit/should_honor_dataFetcherResult_config_completable_future/schema.graphql

@@ -0,0 +1,12 @@
+type DataFetcherResultCompletableFutureType {
+  stringField1: String
+  stringField2: String!
+  booleanField1: Boolean
+  booleanField2: Boolean!
+  integerField1: Int
+  integerField2: Int!
+  listField: [String!]!
+  listField2: [String]!
+  listField3: [String!]
+  listField4: [String]
+}

test/unit/should_honor_dataFetcherResult_config_suspend/codegen.config.ts

@@ -0,0 +1,11 @@
+import { GraphQLKotlinCodegenConfig } from "../../../src/plugin";
+
+export default {
+  resolverInterfaces: [
+    {
+      typeName: "DataFetcherResultSuspendType",
+      classMethods: "SUSPEND",
+      dataFetcherResult: true,
+    },
+  ],
+} satisfies GraphQLKotlinCodegenConfig;

test/unit/should_honor_dataFetcherResult_config_suspend/expected.kt

@@ -0,0 +1,17 @@
+package com.kotlin.generated
+
+import com.expediagroup.graphql.generator.annotations.*
+
+@GraphQLValidObjectLocations(locations = [GraphQLValidObjectLocations.Locations.OBJECT])
+open class DataFetcherResultSuspendType {
+    open suspend fun stringField1(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): graphql.execution.DataFetcherResult<String?> = throw NotImplementedError("DataFetcherResultSuspendType.stringField1 must be implemented.")
+    open suspend fun stringField2(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): graphql.execution.DataFetcherResult<String> = throw NotImplementedError("DataFetcherResultSuspendType.stringField2 must be implemented.")
+    open suspend fun booleanField1(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): graphql.execution.DataFetcherResult<Boolean?> = throw NotImplementedError("DataFetcherResultSuspendType.booleanField1 must be implemented.")
+    open suspend fun booleanField2(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): graphql.execution.DataFetcherResult<Boolean> = throw NotImplementedError("DataFetcherResultSuspendType.booleanField2 must be implemented.")
+    open suspend fun integerField1(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): graphql.execution.DataFetcherResult<Int?> = throw NotImplementedError("DataFetcherResultSuspendType.integerField1 must be implemented.")
+    open suspend fun integerField2(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): graphql.execution.DataFetcherResult<Int> = throw NotImplementedError("DataFetcherResultSuspendType.integerField2 must be implemented.")
+    open suspend fun listField(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): graphql.execution.DataFetcherResult<List<String>> = throw NotImplementedError("DataFetcherResultSuspendType.listField must be implemented.")
+    open suspend fun listField2(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): graphql.execution.DataFetcherResult<List<String?>> = throw NotImplementedError("DataFetcherResultSuspendType.listField2 must be implemented.")
+    open suspend fun listField3(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): graphql.execution.DataFetcherResult<List<String>?> = throw NotImplementedError("DataFetcherResultSuspendType.listField3 must be implemented.")
+    open suspend fun listField4(dataFetchingEnvironment: graphql.schema.DataFetchingEnvironment): graphql.execution.DataFetcherResult<List<String?>?> = throw NotImplementedError("DataFetcherResultSuspendType.listField4 must be implemented.")
+}

test/unit/should_honor_dataFetcherResult_config_suspend/schema.graphql

@@ -0,0 +1,12 @@
+type DataFetcherResultSuspendType {
+  stringField1: String
+  stringField2: String!
+  booleanField1: Boolean
+  booleanField2: Boolean!
+  integerField1: Int
+  integerField2: Int!
+  listField: [String!]!
+  listField2: [String]!
+  listField3: [String!]
+  listField4: [String]
+}

test/unit/should_honor_resolverInterfaces_config/codegen.config.ts

@@ -27,5 +27,9 @@ export default {
       typeName: "MyIncludedResolverTypeWithNullDataFetchingEnvironment",
       nullableDataFetchingEnvironment: true,
     },
+    {
+      typeName: "MyTypeWithPartialData",
+      dataFetcherResult: true,
+    },
   ],
 } satisfies GraphQLKotlinCodegenConfig;