From 2e9ce4a1187fe2c08ecc50a8c5d787924784e674 Mon Sep 17 00:00:00 2001
From: veemakama <makamaveronica98@gmail.com>
Date: Mon, 31 Aug 2026 07:35:34 +0100
Subject: [PATCH]  Bug: GraphQLIndexer.query ignores GraphQL-level errors in an
 HTTP 200 response

Updated File
---
 src/indexer.ts                                | 23 ++++++++++++++++++-
 src/tests/graphql-indexer-memory-leak.test.ts | 22 ++++++++++++++++++
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/src/indexer.ts b/src/indexer.ts
index 9eb8873..35e5bf5 100644
--- a/src/indexer.ts
+++ b/src/indexer.ts
@@ -1,3 +1,5 @@
+import { ConduitError, UNKNOWN_CONTRACT_ERROR_CODE } from './errors.js';
+
 export interface GraphQLQueryOptions {
   query: string;
   variables?: Record<string, unknown>;
@@ -82,7 +84,26 @@ export class GraphQLIndexer {
       throw new Error(`GraphQL query failed with status ${response.status}: ${response.statusText}`);
     }
 
-    return (await response.json()) as unknown;
+    const body = (await response.json()) as {
+      data?: unknown;
+      errors?: unknown[];
+    };
+
+    if (Array.isArray(body?.errors) && body.errors.length > 0) {
+      const messages = body.errors
+        .map((error) => {
+          if (error && typeof error === 'object' && 'message' in error) {
+            const message = (error as { message?: unknown }).message;
+            return typeof message === 'string' && message.length > 0 ? message : JSON.stringify(error);
+          }
+          return String(error);
+        })
+        .filter((message) => message.length > 0);
+
+      throw new ConduitError('stream', UNKNOWN_CONTRACT_ERROR_CODE, messages.join('; '));
+    }
+
+    return body?.data;
   }
 
   subscribe(options: GraphQLSubscriptionOptions): IndexerSubscription {
diff --git a/src/tests/graphql-indexer-memory-leak.test.ts b/src/tests/graphql-indexer-memory-leak.test.ts
index 80cd5f0..3e2042f 100644
--- a/src/tests/graphql-indexer-memory-leak.test.ts
+++ b/src/tests/graphql-indexer-memory-leak.test.ts
@@ -69,6 +69,28 @@ describe('GraphQLIndexer Memory Leak & Real Network I/O Tests', () => {
     indexer.cleanup();
   });
 
+  it('throws when a GraphQL response contains query-level errors despite HTTP 200', async () => {
+    vi.spyOn(globalThis, 'fetch').mockResolvedValue({
+      ok: true,
+      status: 200,
+      json: async () => ({
+        data: null,
+        errors: [
+          { message: 'Cannot query field "doesNotExist" on type "Query".' },
+          { message: 'Resolver error: boom' },
+        ],
+      }),
+    } as Response);
+
+    const indexer = new GraphQLIndexer(endpoint);
+
+    await expect(indexer.query({ query: 'query { doesNotExist }' })).rejects.toThrow(
+      'Cannot query field "doesNotExist" on type "Query".'
+    );
+
+    indexer.cleanup();
+  });
+
   it('subscribes and properly cleans up active subscriptions on unsubscribe()', async () => {
     const indexer = new GraphQLIndexer(endpoint);