From 13c24883004d5330f7402cb20566e37535c5729b Mon Sep 17 00:00:00 2001
From: Arda TANRIKULU <ardatanrikulu@gmail.com>
Date: Wed, 7 Dec 2022 15:46:12 +0300
Subject: [PATCH] fix(delegate): handle existing argument nodes correctly

---
 .changeset/cold-files-drive.md                  |  6 ++++++
 packages/delegate/src/finalizeGatewayRequest.ts | 11 ++++++++++-
 packages/utils/src/transformInputValue.ts       |  3 ++-
 3 files changed, 18 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/cold-files-drive.md

diff --git a/.changeset/cold-files-drive.md b/.changeset/cold-files-drive.md
new file mode 100644
index 00000000000..5308652d006
--- /dev/null
+++ b/.changeset/cold-files-drive.md
@@ -0,0 +1,6 @@
+---
+'@graphql-tools/delegate': patch
+'@graphql-tools/utils': patch
+---
+
+Fix handling argument values in gateway request
diff --git a/packages/delegate/src/finalizeGatewayRequest.ts b/packages/delegate/src/finalizeGatewayRequest.ts
index 188bfd343f0..aec7447b35a 100644
--- a/packages/delegate/src/finalizeGatewayRequest.ts
+++ b/packages/delegate/src/finalizeGatewayRequest.ts
@@ -16,6 +16,7 @@ import {
   SelectionSetNode,
   TypeInfo,
   TypeNameMetaFieldDef,
+  valueFromAST,
   VariableDefinitionNode,
   versionInfo as graphqlVersionInfo,
   visit,
@@ -221,6 +222,14 @@ function updateArguments(
     const argType = argument.type;
 
     if (argName in newArgs) {
+      let value: any;
+      const existingValueNode = argumentNodeMap[argName]?.value;
+      if (existingValueNode != null) {
+        value = valueFromAST(existingValueNode, argType, variableValues);
+      }
+      if (value == null) {
+        value = serializeInputValue(argType, newArgs[argName]);
+      }
       updateArgument(
         argumentNodeMap,
         variableDefinitionMap,
@@ -228,7 +237,7 @@ function updateArguments(
         argName,
         generateVariableName(argName),
         argType,
-        serializeInputValue(argType, newArgs[argName])
+        value
       );
     }
   }
diff --git a/packages/utils/src/transformInputValue.ts b/packages/utils/src/transformInputValue.ts
index ef0318a8967..d2465cfe7cc 100644
--- a/packages/utils/src/transformInputValue.ts
+++ b/packages/utils/src/transformInputValue.ts
@@ -1,4 +1,5 @@
 import { GraphQLInputType, getNullableType, isLeafType, isListType, isInputObjectType } from 'graphql';
+import { asArray } from './helpers.js';
 
 import { InputLeafValueTransformer, InputObjectValueTransformer, Maybe } from './types.js';
 
@@ -17,7 +18,7 @@ export function transformInputValue(
   if (isLeafType(nullableType)) {
     return inputLeafValueTransformer != null ? inputLeafValueTransformer(nullableType, value) : value;
   } else if (isListType(nullableType)) {
-    return value.map((listMember: any) =>
+    return asArray(value).map((listMember: any) =>
       transformInputValue(nullableType.ofType, listMember, inputLeafValueTransformer, inputObjectValueTransformer)
     );
   } else if (isInputObjectType(nullableType)) {